Cambridge Approaches

Introduction

The article below has been written by an anonymous Cambridgeshire contributor who has a keen passion for, and knowledge of, railways. The previous article on this subject showed that the general capacity of the existing twin track between Cambridge Station and Milton Junction was sufficient to take the existing traffic, planned growth and EWR trains without the need for 4-tracking.

In discussions and correspondence with EWR Co, it was clear that they have carried out their assessment based on the current timetable. They claim that this showed that 4-tracking of this section of the track would be required. Our previous article suggested that this was unnecessary as the current timetable would change over the next 10 years before EWR became operational.

However, to address EWR Co’s specific concerns, we have looked at the issues that they raise with the timetable and show that, with a minor revision, even on this basis there is no need to 4-track this track.

Summary

EWR Co’s argued need for 4-tracking in the north of Cambridge in a ‘northern approach’ scenario – which underpins their decision to discount that option in the latest consultation – is based on concerns about interfacing with current operations. EWR Co have not published their full analysis, but state that they cannot fit EWR trains at regular 15 minute intervals alongside the existing timetable. While that statement appears to be technically true (in the most tenuous sense), the analysis presents here suggests that without context, it is likely highly misleading – and 4-tracking is certainly not the only solution. The issue is not too many trains, but a few quirky ‘symmetry breaking’ inefficiencies in the current timetable (particularly the fast/slow Liverpool Street trains). The immediate EWR issue can be solved by slipping a single hourly train by a single minute, and even if we are to future-proof to include the reasonable-worst-case scenario (including a variety of other future trains beyond EWR), only very minor tweaks to the existing are needed to make it work. Once Cambridge to Liverpool Street services are expanded to four an hour (expected in a similar timeframe to EWR’s construction), the asymmetry issues will have resolved themselves anyway – so it is illogical to let such quirks control EWR’s design decisions.

1.      Introduction

(I suggest you grab a cuppa and get comfortable before you continue, as this is quite a long and technical post)

I should start by saying that I’m not a campaigner and am not necessarily pushing for any particular outcome. Having seen the significant campaigning efforts of Cambridge Approaches, CBRR and others, however, I thought it would be interesting to delve into the ‘north vs south’ arguments from an objective viewpoint, to try and determine whether or not the proposed northern approach is actually a viable alternative. A few months of late-night analysis later, and yes, I do think there are – potentially – some aspects which may have been overlooked. I am not an industry expert and am of course willing to be stand corrected if I have missed something important, but am keen to open the discussion so that we maximise our chances of building the best railway possible. Although EWR Co have published many pages of technical documents describing the consequences of 4-tracking, they have unfortunately still not provided a robust technical justification for why they think it is necessary – instead simply claiming that they have “looked at it and concluded that it’s the only solution”. This makes it very difficult to peer review their work and assess the validity of their argument, so some guesswork is required in attempting to re-trace their steps. I’ve tried to present everything as clearly and transparently as I can in this document, so people can see the arguments for themselves.

If, as EWR Co claim, the only way to add four hourly EWR trains through Cambridge North is to add a second pair of tracks through the north of Cambridge, then the associated destruction of nearby properties and other infrastructure costs are very significant (as the infamous “appendix F” goes to great lengths to illustrate). These consequences feature front-and-centre in EWR Co’s justification for discounting a northern approach, and I suspect finding a way to avoid 4-tracking is at the core of the northern approach’s viability.

If my analysis has missed some vital other reason why 4-tracking really is the only solution, then the proposed southern approach certainly has its relative merits. However, there is still a possibility that as even more Cambridge-London trains are added, sending EWR trains into Cambridge from the south might mean it isn’t long before the track from Shelford to Harston needs 4-tracking, alongside grade separation of the Shelford junction, both of which would also be highly disruptive.

2.      Mapping the new railway

In the vector diagram below, every line corresponds to a single hourly train in each direction at present (except for the orange freight line, which is just indicative of routes).

The next diagram is a best guess at how EWR Co’s proposed ‘southern approach’ might look. This analysis is based on an assumed 4 trains an hour, which would be in line with the busiest UK inter-city services running today. I’ve included the potential Wisbech line (either running from Cambridge or splitting from existing trains at Ely), added second hourly trains to both Norwich and Ipswich, and extended a second hourly London train from Ely to King’s Lynn. This gives us a reasonable upper bound for the next few decades to the north and east. I’ve not added potential extra trains south of Cambridge, such as the mooted services to Maidstone or Haverhill, or additional London services (at least three of which are included in Network Rail’s 2030/40 scenarios). There is still some uncertainty about how EWR would be timetabled: I’ve taken the ‘best case’ scenario where Norwich keeps its direct Stansted service, but otherwise 3 of 4 EWR trains continue to Norwich (1/h) and Ipswich (2/h). EWR, then, serves Cambridge South and Central stations with every train; Cambridge North only sees a single hourly EWR service.

Next, we have a potential ‘northern approach’. The same extra services are assumed as above, but EWR now arrives via a junction at Milton rather than Harston. There’s an optional station at Northstowe (and space still for one at Harston too), and 4-tracking may only need to go as far as Cambridge South. In this scenario, the ‘base case’ is that EWR trains all serve all three Cambridge stations, terminating at Cambridge South. There are options, such as linking with existing London (if electrified), Stansted and/or a reopened Haverhill line, or reversing at Cambridge in order to continue towards Norwich/Ipswich. It is a requirement that EWR’s design does not preclude the latter as an option, though it is probably not the most beneficial solution. Freight mostly avoids Cambridge via a new chord south of Ely. This would, admittedly, be expensive to construct (as it would include a new bridge over the Cam), but could remove freight from the single-track Newmarket route, reducing the need to dual quite as much of it.

3.      Improving existing layouts

It is clear from the northern approach diagram that the section through the north of Cambridge is quite busy – so at first glance the argument for 4-tracking seems reasonable. But can it be avoided? The first step is to see what can be done, with only modest adjustments, to increase efficiency in that section. South of Cambridge (central) station we will have 4 tracks, a grade-separated Milton junction confers no additional capacity constraints, so the solution hinges on just the three miles of twin tracks between Cambridge’s central and north stations.

Two hourly Liverpool Street trains terminate at Cambridge North (except for 2/day to each of Ely and King’s Lynn). When they head back south, they block the northbound track until they reach the switch point south of the river. However, this can easily be avoided by moving the terminus platform from the west to the centre. Although it should not be necessary, the through-platforms could be doubled up: There’s space for the western one within the existing footprint, while a 5^th on the eastern side will probably take a sliver of land from neighbouring properties. In the very worst-case scenario, if no extra land is available, then there is space further north to stagger northbound and southbound platforms. If, as has been suggested, the two Liverpool Street trains will in future need to continue to Ely, then a terminus here is not required, and either 2 or 4 platforms would suffice.

Cambridge Central is a large and complex station, currently having four terminus and four through-platforms (the latter all serving trains in both directions). The terminus platforms are all on the western side, so reversing trains again obstruct oncoming traffic as they switch tracks. According to Network Rail’s 2019 report, a southern approach would see a new island pair of through-platforms to the east, and 3-tracking to the Coldham’s Lane junction, as shown on the right in the figure below.

There are many possible iterations for upgrading the station in a northern approach scenario. The first obvious step is to swap Ipswich/Newmarket trains onto a new eastern platform. Without the need to weave Newmarket-bound trains across from the eastern side of the Shelford junction as they approach from Oxford, it should be possible to separate them entirely from other services via 3^rd track to the east towards the Coldham’s Lane junction. Ipswich trains currently only dwell at Cambridge for about five minutes, so even with two or more such services an hour, a single platform and single track under Coldham’s Lane bridge should be sufficient, assuming most freight is diverted via a new spur near Ely.

It may make sense to tidy the central portion of the station into a pair of northbound and a pair of southbound platforms. In a similar approach to Cambridge North mentioned above, it might also be possible to allocate a terminus-priority platform in the middle (the current platform 7) which could eliminate at-grade crossings on the section we’re interested in. This platform could be extended to the south, to also provide a central terminus for trains from London. If the latter option is chosen, platforms 5 and 6 might even become redundant: paved over, they’d make the ideal location for a second station entrance, providing a much shorter route from cycle parking to the platform bridge, and additional income from renting out retail space.

It is worth noting that Cambridge central station is more constrained to the south than the north: the Hills Road bridge is just 100 metres beyond the end of platform 1 (and only four tracks wide), and the post office building & car park limits space to the southeast. At present, there is space for the existing platform island to be extended further south – though if the new eastern platform island were connected to the south, this option may become less viable. In a northern approach scenario, there is much better balance in the number of trains heading north vs south in and out of Cambridge, which should reduce the pressure on platform space and time from terminating services.

For completeness, we should mention Cambridge South. In the southern approach proposal, it has four platforms – two pairs serving ~14/h in each direction (plus any future London services). In a northern approach scenario it may serve slightly fewer trains, but some might terminate at the station. It should be possible for a single platform to cope with as little as 3 minutes between trains (see Tottenham Hale’s southbound platform 1, for example), but in the worst-case scenario a 5^th platform may be required here, offering a central terminus and two through-platforms in each direction. Although there would be some opposition to encroachment on Hobson’s Park, the additional land and cost would be very modest (just the width of a single-track path, as the current proposed station design already has the requisite platform island). If few EWR trains terminate here (instead continuing south to a combination of Haverhill, London, Stansted or elsewhere), the chance of needing a 5^th platform is reduced, but 4-tracking may instead need to continue to the Shelford junction – as is the case for a southern approach scenario.

With a little effort, then, it should be possible (if needed) to entirely eliminate at-grade crossings on the busy section we’re interested in, between Cambridge and Cambridge North. We therefore have a simple scenario of twin tracks, around a dozen trains per hour, and no clashes or constraints linking the two directions. Fewer freight trains should need to use this route (with as many as possible moved to EWR and an Ely chord), so trains should follow very similar acceleration profiles on this short, slow section of track. Nonetheless, we will still aim to ensure one oversized hourly slot remains for freight just in case (because getting as much freight off of the road and onto rail is very much to be encouraged).

If we look at the existing timetables, we see that the minimum gap between trains leaving Cambridge to the north is 3 minutes (xx:00 and xx:03 Cross-Country and Great Northern respectively). A 3-minute headway is also what’s stated in EWR’s requirements [Appendix B 5.7.2 of the latest EWR Co consultation docs] – so we can safely assume this is our minimum acceptable gap. Indeed, it only takes about 3 minutes between leaving one station and arriving at the other, so even spaced this close together, we should never have two trains between the two stations at the same time.  

I should note that the Cross-Country train does not currently stop at Cambridge North station – so despite many examples to the contrary, such as Tottenham Hale mentioned above, EWR Co may still conclude in the worst-case scenario that Cambridge North requires expansion to twin platforms in each direction. This is an expense not required with a southern approach, but that’s only because in a southern approach few (if any) EWR trains actually serve Cambridge North.

4.      Symmetry and inefficiency – the spectre of 4-tracking

In an idealised world without external constraints, 3-minute headings should allow for a theoretical maximum of 20 ‘slots’ per hour (up to 15 of which can be used if we are to stick within the 0.75 resilience requirement). With this in mind, EWR Co’s argument that even the 6 current + 4 EWR trains cannot be accommodated without quadrupling the tracks has led to much head-scratching. So, what is going on; how is the real world so far from ideal that we can’t even manage what is – without even considering future signalling upgrades – just ~50% theoretical capacity?

Although EWR Co have still not published their actual analysis (only the consequences thereof), I recently managed to speak to EWR Co’s Paul Sparrow via their live chat events, and obtained slightly more insight into their analysis:

“We have used some operations specialists to conduct the assessment using rail operations modelling systems in order to ascertain where we could get our 4 trains per hour onto the existing twin track WAML using our regular 15 min clockface service pattern. These results demonstrated that the white space, the space between trains, does not exist to allow us to get 4 trains an hour every 15 mins.” (Paul Sparrow, 29^th May 2021)

This snippet of information, although still quite cryptic, is perhaps just enough for us to solve the mystery. The issue, I now suspect, is actually quite simple – and it’s all down to symmetry. Despite computational advances, building railway timetables is still ultimately mathematically driven by repeating patterns: it’s what the Swiss call ‘taktfahrplan’, or clock-face scheduling. Most train lines interact with several others along the length of their routes, and weaving all of these interconnected requirements together without clashes is much easier if everyone is dancing to the same beat. Although modern timetables may look quite random, they are essentially still just perturbations on an underlying regular symmetry.

We can illustrate this with a simplified example. Consider a railway line serving four locations: Appletown and Bananaville each need four trains an hour; Carrotbridge and Donutland need two apiece. Treating C&D as a single set, we can schedule these 12 trains at 5-minute intervals, with a pattern repeating every 15 minutes (left clock-face below). However, what if Carrotbridge decide they need their pair of hourly trains spaced 20 minutes apart? We start with Appletown’s regular trains, but once we’ve added Carrotbridge’s symmetry-breaking requirements, there’s no space left for Bananaville to have a train every 15 minutes. We can squeeze in the pair of Donutland trains, but the remaining slots are unhelpfully distributed – poor Bananaville!

This scenario is conceptually very closely related to the issue we have at hand. Carrotbridge in this case is represented by the Greater Anglia trains to Liverpool Street – and Bananaville is Oxford!

The two hourly trains from Cambridge North to Liverpool Street arrive in London at regular half-hour intervals. However, one of them is slightly ‘fast’ and the other ‘slow’: the difference is a modest ~10 minutes (~1h10 vs ~1h20). In order to make this work, 30 minutes after the slow train has left Cambridge North, the fast train…sits there for another 10 minutes, and then departs. By stopping at fewer stations on route, by the time it reaches London it has caught back up again to the 30-minute periodicity. On the return leg back north, the fast train arrives back 10 minutes earlier than its slow train equivalent would have done, and so it ends up sitting at Cambridge North…for yet another 10 minutes.

The other trains all tend to run at roughly regular half-hourly slots, into which it would normally be quite easy to add an EWR train every 15 minutes, because their symmetries are in sync. The Liverpool Street train’s timings, however, makes this simple task so much more difficult. As we will see, there are a few other minor quirks in the existing timetables too, all of which can be dealt with quite easily.

5.      Building more efficient timetables

Let us consider how this would work in terms of timetables. We’ve removed all at-grade crossings from the section, and Newmarket-bound trains have been moved onto a separate track. This should make our task relatively straightforward, as we have a single stretch of dual track between Cambridge Central and Cambridge North, with one train simply following the one in front. This is the most constrained section, so if it can be shown to work then everything else should fall into place.

We can start with the current timetable, and then see how the new services might look added in the ‘white space’. In this example, a normal weekday between 1pm and 2pm has been used – the differences from hour to hour are quite minor, so a proof-of-principle assessment needn’t replicate the analysis for every hour of every day. Instead of showing you lots of graphs and lists of timetables, I’ll stick with the ‘clock-face’ diagrams from the Appletown example above.

In the clock-face diagrams below, each service is represented by a 3-minute block, during which no other trains may depart. In the current timetable, we can see the two closest trains’ blocks adjacent to one another at xx:00 and xx03 on the northbound chart, and vast swathes of free ‘white space’ in both directions. These really aren’t very busy lines at the moment, with a train on each track between the stations just 30% of the time! But as you can see, the pairs of trains to Liverpool Street and (in the southbound direction) King’s Cross are not nicely symmetrical, with the Norwich train sitting where one might expect the second Liverpool Street train to be.

Now, if we attempt to add four hourly EWR trains to the existing timetable, it might look something like the figure below. At first glance all seems fine, but on closer inspection one of the four EWR trains has been slipped by a single minute from its ideal 15-minute-interval service, in order to avoid overlapping with an existing train’s 3-minute window. Although you might think this a very minor issue – arising from an existing timetable quirk which will long since have changed by the time EWR is built – as far as I can tell (going by Paul Sparrow’s above quote), it is precisely this which has led EWR Co to claim that the only solution is to build two more tracks through the north of Cambridge!

Nonetheless, sticking for now with the nearly symmetrical EWR trains added alongside the existing timetable, what other services might we need to make room for in the next few decades, to ensure our design is future-proof? A second Norwich train is an obvious one: Northbound it can fit exactly 30 minutes away from the existing train; southbound we have to offset it by a couple of minutes from its ideal position (one bit of broken symmetry forcing another one). After this, there is still space for another half-hourly service (e.g. trains to Wisbech) – and we’re still within the 75% resilience threshold stated in EWR’s requirements [Appendix B 5.7.2]. In both directions, there’s an oversized gap left in the hourly timetable for even a very slow freight train to get through, although this should be avoidable in most instances as freight could travel via Soham or Newmarket instead. We could even (not shown) double up the Birmingham service (which some hope could be extended to Leeds in future), by simply moving the northbound freight slot to ~xx.45.

The figure above illustrates how a northern approach – and a bunch of potential other future services – could work, without any changes to the existing timetable, without any signalling upgrades, and within the documented requirements of headways (3 minutes) and resilience (25% unused wiggle-room), without resorting to knocking down any buildings to build more tracks. However, what if we absolutely must have a symmetrically perfect-to-the-minute EWR service? Or, indeed, what if we would just like to tidy up the existing inefficient broken symmetries, and thus optimise the potential capacity through Cambridge’s only traffic-jam-avoiding cross-city travel corridor?

Northbound, the solution is incredibly simple. The fast train from Liverpool Street (which is about to sit at Cambridge North for more than half an hour) can just wait for a single minute at Cambridge station. That’s it.

Southbound, we have slightly more work to do. First, we align the time for which the King’s Cross trains dwell at Cambridge. I suspect the reason for this asymmetry in the current timetable comes from train-splitting, but with platforms at Ely and Waterbeach due to be extended, Network Rail themselves expect that procedure to be phased out in the coming years. Next, we have the fast Liverpool Street train (which leaves 10 minutes later than symmetry would like), and the existing Norwich train (which is then in the way). A neat, symmetry-restoring solution (as shown in the diagram below) is to push the Norwich train back by two minutes, and have the fast Liverpool Street train depart Cambridge North 10 minutes early, and dwell at Cambridge for 10 minutes (where it will be overtaken by the Norwich train, and then continue to Cambridge South roughly alongside the EWR service on the quad tracks). This would only be needed until two more (slow) trains between Cambridge Central and Liverpool Street are added, at which point both Cambridge North to Liverpool Street trains can become fast services.

The Norwich train, in ensuring regular hourly cycles, has a few minutes of wiggle-room to play with, but in a worst-case scenario it might miss its Stansted spot – in which case its lost slot could be taken up by an EWR train instead. A slightly less neat, but probably still workable and arguably less disruptive, solution (not shown) would have the existing Norwich train unaffected, the fast Liverpool Street train leaving just a minute or two earlier than it currently does, and the second Norwich train 32 minutes after (or 28 before) the existing one. These solutions involve very minor tweaks to the existing timetables, none of which should have any further knock-on effects on other services.

The above is, I would argue, a reasonable worst-case scenario for the 2040s, and is still acceptable within EWR Co’s given requirements. However, I suspect reality will be less constrained, as there are a variety of possible options which would each reduce the number of trains travelling through the busy corridor.

I would be slightly surprised if EWR needed four hourly trains, at least for the first decade or two. Even the busiest UK intercity services such as London to Bristol only have that many – as does Cambridge to King’s Cross (if we ignore the two slow trains which offer no utility for intercity passengers). EWR only serves relatively small towns and cities, and long-distance trips across the country which really aren’t that popular (and are mostly already quite doable via London, especially once Crossrail is operational). Half-hourly 8-carriage trains would have the same capacity as the proposed four hourly 4-carriage ones, and as EWR doesn’t really serve busy commuter routes east of Bletchley (where it’s expected that another 2/h will run from Oxford to the Milton Keynes  branch anyway), I suspect few would be very upset by a slightly less frequent service. Other than for a few select local routes (such as Cambridge and Bedford residents hopping on the train to Bletchley’s IKEA), EWR provides (at best) a modest improvement rather than a genuine transport revolution. Let’s just hope the trains have enough luggage space for flat-pack bookcases!

Next, it’s worth noting that Wisbech and King’s Lynn are a similar distance from Ely. The fast King’s Cross train, which currently splits at Cambridge (with only the front section continuing further north) could instead continue as one further north beyond the new Milton junction (where the track is less congested). It could then split in half at Ely (or the new Waterbeach station), with the front continuing to King’s Lynn, and the back departing for Wisbech three minutes later.

We could go further still. There are actually two routes from Norwich to Cambridge, of similar length. The route currently operating heads via Ely, but there’s another route via Diss and Bury St Edmunds. A direct train using the latter would either need to reverse in Stowmarket, or use a yet-to-be-built spur just north thereof. If a second Norwich train took this route, it would provide direct connections between Cambridge and Diss; Norwich and Bury St Edmunds. Moreover, while a large fraction of trips to Cambridge on the Norwich train involve people travelling the whole length of the line (with small numbers using intermediate stations such as Thetford), most Cambridge arrivals on the train from Ipswich come from Newmarket or Bury St Edmunds. Therefore, instead of having two Norwich trains via Thetford and two Ipswich ones via Bury, sending the second Norwich train via Bury may actually better serve passenger demand – as well as easing Ely’s congestion problems.

As a final potential tweak, it’s worth thinking about how to make best use of the station at Stansted Airport. Airports are the one location where direct trains are hugely advantageous, as swapping trains at intermediate stations is much more difficult if you have heavy luggage in tow (or are jetlagged!). However, the long single-track tunnel under the runway severely restricts how many trains can reach the airport. From Cambridge, two hourly trains make the journey – one from Norwich (Greater Anglia, class 755 diesel/electric hybrid trains) and one from Birmingham (Cross-Country, class 170 diesels). Could we use the advent of “Great British Railways” to shuffle rolling stock around, and thus find a way for these two trains to join together (at Ely or Waterbeach) and travel as one to Stansted? GA has a whole bunch of class 755s on local routes, a few of which could perhaps be swapped for CC’s class 170s – and I see no reason why the resulting 755 pair couldn’t couple together. This would then free up a Stansted slot, which (in a northern approach scenario) could enable an hourly direct EWR train from Oxford to Stansted!

If we put all of the above together in an optimistic scenario for the 2040s, we actually find ourselves with just a single extra train each hour compared with the current timetable (and even that is offset by an expected reduction in freight traffic, given a new spur south of Ely). I appreciate that at least some of the suggested optimisations might prove unworkable, but nonetheless it reinforces how many different options there are for ensuring there is absolutely no need to four-track through the north of Cambridge in a northern approach!

6.      Has this solved the problem?

The above examples show that there doesn’t appear to be any fundamental issue with scheduling all the trains we might possibly need in a way which avoids the need for 4-tracking. None of the tweaks suggested should cause any knock-on effects, so could be achieved while keeping all other timetables intact. Passengers boarding at Cambridge North towards Liverpool Street may see their southbound journey time increased by a few minutes – but I suspect that is an acceptable price to pay, given that a northern approach (unlike a southern one) would bring a regular EWR service to Cambridge North.

However, it is worth stressing that by 2030 (when EWR is expected to begin operation), the current franchises will be long gone: The current Greater Anglia franchise ends in 2025, and Great British Railways is about to completely shake up the way franchises work in the UK anyway. As such, so long as the *principle* of operation is sound, it’s not really worth worrying in fine detail what the precise timetables will look like at this stage – because they’ll all have changed by the time the line is built in any case.

It is, of course, worth noting that even in a southern approach scenario, the frequency of trains will increase – and symmetry-breaking carbuncles, which massively reduce line capacity, will need to be phased out regardless. The Liverpool Street asymmetry will probably be eliminated entirely within a few years anyway, as we expect to require a new pair of WAML trains which terminate at Cambridge Central. With four hourly trains in total, the Cambridge North pair will almost certainly both be designated as similarly ‘fast’, At which point the whole asymmetry issue disappears!

When designing new, it is always better to start as cleanly as possible, rather than adding yet more mess on top of existing inefficiencies. As the existing quirks can be easily tidied up – and will probably need to be resolved soon anyway – it would be wholly irrational to base major infrastructure design decisions around them. Nonetheless, given EWR Co’s claimed arguments, I thought it useful to illustrate how I think 4-tracking can be avoided both in principle, and in practice around the current timetable.

I haven’t considered in detail the extra services to London which Network Rail’s forecasts indicate will be needed by 2040. Most of these won’t pass north of Cambridge Central, so will not affect a northern approach. Looking at NR’s worst-case 2043 scenario, the only extra services needed north of Cambridge are one or two more Ely-KX trains (which could be the Wisbech trains, already factored into my model) and extending the two existing Liverpool Street trains beyond Cambridge North to terminate at Ely (which would remove the need for a 5^th platform at Cambridge North, but add no further constraint issues so long as the junction at Milton is grade-separated). On the other hand, they will add further pressure to a southern approach, which even with 4-tracking may find the south Cambridge corridor eventually becomes problematically congested – risking platform capacity issues at Cambridge Central from so many terminating trains, and perhaps a need to rebuild Shelford junction as grade-separated.

7.      Concluding remarks

EWR’s Paul Sparrow has stated that the existing timetable doesn’t “allow us to get 4 [EWR] trains an hour every 15 mins” for a northern approach. The analysis presented here appears to confirm that this is technically a correct statement, but – unless I am very much mistaken – only in the same kind of way that I can say I was Time Magazine’s Person of the Year in 2006: It’s only *just* correct, and likely very misleading for them to have used it to draw the conclusions they have.

EWR Co claim that the only solution to the above, in a ‘northern approach’ scenario, is to 4-track north of Cambridge station. I disagree. The immediate EWR issue can be solved by slipping a single hourly train by a single minute, and even if we are to future-proof to include the reasonable-worst-case scenario (including a variety of other future trains beyond EWR), only very minor tweaks to the existing timetable – which will almost certainly disappear soon anyway – are needed to make it work.

If my analysis turns out to be sound, then I do not understand why EWR Co decided that 4-tracking (with dozens of demolitions, new bridges etc) is considered a lesser evil. I accept that there may be additional complications of which we are not aware, and which render the proposals in this document unworkable – but if that is the case, then they absolutely must be able to explain to the public why this is the case, and cannot continue to simply state “our modelling says it is not possible” without offering a technical justification.

If the timetabling issue can be resolved and 4-tracking rendered unnecessary, the question of a northern vs southern approach becomes much more balanced. I will leave it to others to expound the pros and cons of each option, but advantages such as keeping more freight out of Cambridge, EWR regularly serving Cambridge North (and potentially also London and/or Stansted), the option of a station at Northstowe (offering direct links to Cambourne, Oxford and Addenbrookes), an easier way to get the Haverhill line back up and running (without it adding even more N-v-S imbalance to the numbers of trains running through the Cambridge corridor), and simplifying the process of electrification between Oxford and Cambridge by decoupling from the Eastern section (not due for upgrade until 2040-50)…are all worth thinking about very seriously indeed.

Why do we need to know about 4-tracking?

EWR Co’s decision to prioritise a southern approach into Cambridge primarily hinges on their assertion that a northern approach will require to be 4-tracked from the Milton junction with the existing West Anglia Main Line (WAML) into Cambridge. They also say that the existing Shepreth Branch Line between Hauxton Junction and Shepreth Junction (SBR) does not need to be 4-tracked but accept that this assessment needs further testing in later design stages.

It is vital that these matters are properly assessed now. To implement 4-tracking on either of these sections of existing lines would be extremely expensive. Major existing bridges would need to be modified or rebuilt and other infrastructure modified. If it is not resolved now, detailed design work would proceed based on a potentially faulty premise with the risk of locking the project into a solution that will lose valuable benefits of the alternative route.

To test EWR Co’s assessment, we have carried out our own evaluation of both their claims. We start by looking at the likely number of trains on the sections of the lines in question. We estimate the total number of trains likely to use the line including current traffic and probable growth for both passengers and freight. We discuss the likelihood of each of the scenarios occurring in practice and compare these rail traffic estimates with the capacity of the lines.

Summary

We found that EWR Co’s conclusion about the 4-tracking of the northern approach section NA2 is incorrect and that, for our estimate of the reasonable worst-case scenario, it does not need additional tracks. In fact, even with just traditional signalling there is likely to be sufficient capacity. With digital signalling, which is already specified by EWR Co, we expect there to be over-capacity.

Likewise, the southern approach section of the SBR line can probably take the reasonable worst-case passenger rail traffic estimate (which are based on Network Rail’s figures up to 2044). However, interfacing with the Thameslink services will impose severe restrictions on possible growth in traffic in excess of the figures shown due to anticipated expansion after 2044 as a result of the Ox-Cam Arc plans. The SBR line would not be able to accommodate EWR’s 6 trains per hour that are specified in the Project Wide Output Specification. The freight services estimated by Network Rail may not be able to be fully catered for because of limitations on the Newmarket line.

If EWR Co are wrong in their assertion that the SBR line does not need to be 4-tracked, the construction work that would be required exceeds the theoretical (but unrealistic) case for 4-tracking part of the northern approach.

Rail Traffic

The reasonable worst-case rail traffic scenarios for the northern and southern approaches to Cambridge are shown in Table 1. For the northern approach, we have considered the likely rail traffic on the critical section between Milton junction and Coldham’s Lane. All Newmarket trains would use platform 8 at Cambridge station enabling those services to avoid crossing movements between Cambridge Station and Coldham’s Lane. There is sufficient space in that length to increase the number of tracks should this be required.  

The assumptions and data sources used in compiling Table 1 are discussed below.  

• We have not assumed any long-term change in the pre-pandemic forecasts for growth and and ‘existing’ services due to impact of COVID, even though this is likely to reduce the amount of rail traffic in the short and perhaps the medium term.
• For consistency and independence, we have used Network Rail’s 2019 Cambridgeshire Corridor Study [Ref. 1] for assessing passenger and freight growth forecasts on the existing network for the two approaches. This will allow a fair operational comparison to be made between the approaches. We have resisted the temptation to consider in this assessment the beneficial effects (for a northern route) of an alternative future route via Newmarket for Norwich trains which has been suggested for many years, or the possibility of March trains splitting/joining other services at Ely. Combined, these could potentially reduce demand on the northern approach by 3tph. Nor have we considered the impact of a potential new Thameslink service between Cambridge and Maidstone East which may increase demand on the southern approach. Lastly, we consider that, if the Ox-Cam Arc proceeds as planned, there would be demand for even more Kings Cross services than mentioned in the Cambridgeshire Corridor Study with a timescale to 2044 only.
• Future demand for freight on EWR is taken from a scenario suggested by Network Rail in the EWR Co’s Technical Report 3.10.7.
• For a northern approach, EWR freight would be diverted northwards onto the WAML from Milton via a new grade-separated junction and then onto the main Felixstowe to Nuneaton freight line via a new chord just south of Ely. Any residual freight needing to pass through Cambridge would be planned out of peak hours.

Capacity

Basic ‘open-track’ Assessment

In addition to the basic number of trains per hour that could use an open railway line, the capacity is affected by a number of other factors, including timetabling, any crossing movements between tracks, whether the section of track is between junctions or between stations and the mixture of freight and passenger services. We start by looking at the open-line capacity and then go on to consider these other issues.

(i) Traditional signalling

Traditional signalling systems would allow for about 15 trains per hour with no other compounding factors. This is based on international standards (International Union of Railways or UIC which is the international rail transport industry organisation); a headway (the time between trains) of 3 minutes, as convention and a minimum required by EWR Co (Technical Report Appendix B 5.7.2); and a resilience ‘safety factor’ of 0.75 (UIC Code 406 for mixed traffic lines). The reasonable worst-case scenarios for both the northern and southern approaches as shown in Table 1 appears to be within the capacity of the existing twin track based on open track conditions and traditional signalling.

(ii) Digital Signalling

However, digital signalling will be used by EWR [Ref. 2] One of the benefits of digital signalling is the additional capacity that it provides. UIC have shown that on main railway lines, the capacity increase of ETCS level 2 (with ‘block’ lengths of 400m) over ETCS level 1 could be about 37% [Ref. 3]. This is supported by a statement by Network Rail quoting capacity increases ‘of up to 40%’ [Ref. 4]. These figures should be used with care, but they demonstrate that there would be a real and significant increase in capacity. Even using a capacity increase of half of these amounts, the number of trains per hour able to be accommodated could be increased to 18 by digital signalling without the need for 4-tracking,again without any complicating location-specific issues.

Importantly, digital signalling will also allow bi-directional running on tracks. This can provide significant flexibility, especially at stations, for reversing trains.

Other Factors in Capacity Assessment

There are several factors that could reduce actual capacity on a line, including whether clock-face timetabling is used (which is it on EWR) and the number of crossing of main lines radiating from London. Below we only consider those issues that are different between approaches.

(a) The Thameslink Effect and Slow Trains

Capacity reduction can arise when other train services use the section of track and the times of those services are not possible to change. This occurs for the southern approach where Thameslink services use the track. This leads to tight and sensitive interfaces with those services. The result is that the existing 6 passenger services are almost immutable because they form part of the complex Thameslink network and the East Coast Main Line traffic. The complexity of Thameslink can clearly be seen in the map[5] below, especially all the strands of services coming together in central London where it is planned to have 24tph crossing the Thames (which, incidentally, would not be possible without the capacity-enhancing benefits of digital signalling). EWR Co are very likely to be faced with predetermined ‘paths’ (planned slots for trains) at the Cambridge end of the route that do not mesh with their required paths elsewhere. This poses a serious risk to the effective capacity of this line, the outcome of which can only be resolved when timetabling of services is attempted. This is not the case for the northern approach.

If that were not sufficiently restrictive to the timetable, this line also has a slow service calling at all stations without a ‘loop’ or overtaking section for faster trains before they reach the East Coast Main Line near Hitchin. This means that timetabling for fast trains needs to allow for these slow trains, which will lead to greater gaps between trains. There are minimal such restrictions for a northern approach.

(b) Crossing Movements and Junctions

Crossing movements required across other tracks and junctions can also reduce the capacity of a line. In the case where junctions are flat (‘at-grade’), one train joining another line could have to wait if another train were using the section of track the first one wanted to use. ‘Grade-separated junctions’ involving ramps and bridges over lines significantly reduce this delay. The southern approach into Cambridge has two junctions (Hauxton and Shepreth Branch junctions) compared to just one for the northern approach.

The northern approach allows trains that are temporarily blocked by other trains to wait for a short time at Cambridge North station. This would allow following trains to also wait at Cambridge North (obviously on another platform) and so minimise any concertina-type delay. On the southern approach, conversely, delayed trains would have to wait in line between junctions, magnifying the impact of such a delay.

(c) Freight

Operationally, slower freight and more speedy passenger services do not mix well. Freight on a northern approach (via a new northbound chord at Milton onto the WAML and then onto the Felixstowe to Nuneaton line via another new chord south of Ely), means that freight would have no impact on EWR operations in the busy section between Milton junction and Coldham’s Lane junction. Conversely, freight and passenger traffic on a southern approach intermingle, potentially resulting in less overall capacity. If the line were eventually used for even slower moving, heavy-haul freight, such as building materials, this would only exacerbate the situation.

For a southern approach, the Cambridgeshire Corridor Study estimates that the Newmarket line, even with the anticipated dualling between Coldhams Lane junction and Teversham, could accommodate 1tph for freight during off-peak hours. Network Rail estimate the freight demand could be 1.3tph during an 18-hour window (i.e. including peak and peak hours), assuming the scenario suggested by Network Rail in the Technical Report 3.10.7. This implies that there could be insufficient capacity on a southern approach for the anticipated freight.

Another operational disadvantage of a southern approach is that because freight needs to pass through Cambridge and Cambridge South stations, the problem of platform provision in both locations would be exacerbated.

What Do EWR Co. Say?

Northern Approach

EWR Co have stated (Appendix F, 2.2.4) that the results of their analysis of a northern approach showed that there would be several conflicting movements between EWR and other services including:

• Trains towards Ely and eastbound EWR services conflicting where EWR services join the WAML; and
• Conflicts on various platforms at Cambridge station.

We find the first point hard to understand as there could be a grade-separated junction at Milton specifically to overcome this issue. We find their conclusion that the only remaining option is ‘to add two extra tracks to the WAML, making it a four-track railway between the new Milton junction and Cambridge station’ (Appendix F 2.2.10) curious when they could much less onerously provide a grade-separated junction at Milton than the 4-tracking option. Confusingly, they then state in Appendix F 2.2.12 that ‘a grade-separated junction is required where the EWR route joins the WAML…’.

The second point would be overcome by the construction of two more platforms at Cambridge station which EWR Co already confirm would have to be done (App F section 2.2.10). Interestingly, they fail to mention that the southern approach also needs two new platforms at Cambridge station (Technical Report 11.1.5 ). Indeed, as we will see later, there is more pressure on Cambridge station platforms from a southern approach because a freight service will need to pass through. CamBedRailRoad documents[1] provide a solution without the need for additional platforms at Cambridge.

Southern Approach

EWR Co state (Technical Report 11.4.1): ‘…it is most likely  that the SBR can remain as a twin track railway as there is sufficient existing capacity to be able to add the EWR services required to achieve the Project Objectives and leave spare capacity for an increase in services in the future.’ (Our underlining). So they have not confirmed this vital point before choosing a southerly route.

They go on to state: ‘The working assumption for the operational timetable will be assessed further in the next design phase to confirm that it is correct. The focus will be on timetable and performance modelling of the SBR to ensure that both the EWR and GTR services can run as required with suitable resilience to allow for delay, disruption, and updates to service patterns.’

They appear to acknowledge from the last statement that there could be a problem of interfacing with existing services but without being explicit about it. The Sponsor’s Requirements (App A, 5.3 and 5.4) oblige them, as far as practical, ‘to be resilient to any periods of poor performance on the wider network’ and to ‘isolate the wider network from any periods of poor performance on the Railway [EWR]’.

We consider that such a fundamental point as this should be resolved at this stage or, if it really cannot be resolved now, to base decisions on a risk-based approach (i.e. they should analyse the chances of success and the costs of each scenario) in making the choice between a northern or southern approach.

EWR Co mention that two more platforms are required at Cambridge station for a southern approach. This it is not necessarily just a case of removing some sidings to add an extra pair of platforms at the east of Cambridge station: the Royal Mail building really isn’t that far away, and may need to be removed or reduced to allow space for the extra switching tracks, particularly if another pair of side-by-side platforms are needed. Additionally, there is a very short distance between the platforms at Cambridge station and Hill’s Road bridge, in which space all the different platform tracks need to condense down to just four tracks. Indeed, that itself could become quite a bottleneck for a southern approach, as each of the various trains from London and Oxford terminating at Cambridge need to reverse & switch on their way back out.

Other Issues With Approaches

Although the above sections attempt to show whether the two approaches need to be 4-tracked, there are other arguments that need to be considered in the choice of route from a railway operations and cost viewpoint.

1. Symmetry

EWR Co state (Consultation Document page 52) that trains using a northern approach would need to terminate at Cambridge South station. Similarly, a southern approach would need to terminate at Cambridge North station since this area is also an important employment hub.

If EWR Co persist in their conviction that a northern approach would need to be 4-tracked south of Milton, a southern approach would also need to be 4-tracked to Cambridge North as it would carry at least the same amount of rail traffic. This means that, according to EWR Co’s logic, 4-tracking on this section would be needed whichever approach were adopted.

We fully understand some of the severe practical difficulties in providing this. But this underscores our assertion that the northern approach, by providing relatively easy access to all three stations in Cambridge, serves Cambridge’s employment needs better than does a southern approach.

2. Risk and Impact on Infrastructure

We have already referred to the risk of EWR Co being wrong in their future assessment of whether the Shepreth Branch line would need 4-tracking between Hauxton and Shepreth Branch junctions. If they were wrong, the structures that would require to be constructed or modified specifically for 4-tracking are:

• M11 crossing
• River Cam crossing
• Widened cutting E between Cam and A1301

The first two items are major construction works in their own right.

This list is in addition to those that are required even if 4-tracking is not required, including:

• Hauxton grade-separated junction,
• Harston level crossing changes,
• A1368 bridge rebuild,
• Hauxton Road level crossing changes,
• A1301 (rebuilt bridge likely if grade-separated junction at Shepreth Branch junction)
• Shepreth Branch grade-separated junction.

Clearly none of these 9 structures would require to be constructed if a northern approach were adopted.

Compare this to the two structures (the level crossing near Milton and the A14 crossing) that EWR Co state would be required if 4-tracking were required for a northern approach (which we, as detailed above, strongly refute). The other structures requiring modification (Fen Road, river Cam crossing, Newmarket Road and Mill Road) would need to be carried out anyway as a southern approach needs to terminate in Cambridge North station (see point 1 above). But all these works are less than those required for a southern approach.

This discrepancy in construction works between the approaches demonstrates EWR Co’s apparently sanguine approach to risk-based decision making.

3. Reversing Move at Cambridge

EWR Co have made much of the fact that a reversing move (i.e. the driver changing ends of the train) would be needed in Cambridge for onward eastbound traffic.

Two points are worth highlighting here. Firstly, it is not much of a penalty at all. A train approaching Cambridge from a southern approach would need to stop in the station for approximately 3 minutes before proceeding. For a train from a northern approach, the maximum time for the driver to change ends is about 5 minutes – a difference of some 2 minutes!

The second point is that onward eastbound passenger services are excluded from EWR Co’s remit. Although they need take such provision into account (the Sponsor’s Requirements 1.6 state that ‘Consideration should be given to the provision of or integration with services beyond the Oxford Cambridge sections…’), using this weak argument against a northern approach highlights their lack of strong arguments. It is especially rich when, in response to our queries about the problems that a southern approach would cause with freight east of Cambridge, EWR Co claim that it is not within their scope.

Conclusions

1. The northern approach would not need to be 4-tracked between Milton junction and Cambridge station for the predicted maximum amount of rail traffic including future expansion of services to Wisbech and Norwich. As a result of digital signalling, it could also cater for EWR Co’s aspiration of 6tph. EWR Co have appeared to ignore a grade-separated junction at Milton in their analysis of 4-tracking of this section.
2. It is not certain whether the southern approach between Hauxton and Shepreth Branch junctions (SBR line) can take any growth in passenger rail traffic beyond EWR’s 4tph until further timetabling work has been carried out by EWR Co. This is because of the severe constraints imposed by Thameslink and other services using the line. It would certainly not be able to provide capacity for the 6tph EWR services stated in the PWOS. This lack of flexibility to provide for growth is contrary to the Sponsor’s Requirements.
3. If EWR Co’s future assessment of the SBR line shows that they do require to 4-track it, the construction works required is likely to exceed the theoretical additional works required for 4-tracking the northern approach (as stated in conclusion 1, they are not actually required).
4. EWR Co have not been transparent about the adverse impact of freight using a southern approach on railway operations.

References

[1] Network Rail Cambridgeshire Corridor Study 2019.
[2] Programme-Wide Output Specification (Technical Report Appendix B 5.20.2) is ‘at least’ European Train Control System (ETCS) Level 2. The current signalling system in the general Cambridge area on existing track (i.e. in addition to the EWR track) is being upgraded to provide a platform ready for digital technologies and is planned to be complete by 2025, five years before the currently planned EWR completion date.
[3] ‘Influence of ETCS on line capacity – generic study’, UIC, Fig 24
[4] https://www.networkrail.co.uk/running-the-railway/railway-upgrade-plan/digital-railway/
[5] By Mvpo666 – Own work, CC BY-SA 4.0,
[6] CBRR Northern Approach Into Cambridge.

Introduction

The EWR Co. 2021 non-statutory consultation includes a policy statement^[1] on noise and vibration in which we find the following statement. “Sometimes we will need to elevate the track, for instance when trains intersect with roads and cross land in a floodplain. However, where it’s practicable we will consider building the track low in the landscape. This can help reduce noise and has the benefit of reducing the impact on the landscape.” 

Although they recognise that it is good to build low in the landscape (and as we shall see, this is good for several more reasons than just noise and vibration), the circumstances where they elevate the railway occur frequently. This has resulted in proposals for the approaches to Cambridge, north or south, which can only be described as a desecration of the landscape in our precious green belt. Indeed, it is hard to overstate the hideous nature of the proposals that we have before us.

This post has been written with the guidance of experienced civil engineers and the hope is to help EWRCo. find a better solution. But it is also to explain to others what is possible and is achieved elsewhere in the world and so to set all our expectations a lot higher. CBRR have, as volunteers, looked at a low impact railway design for the northern approach, but have not done so for the southern approach.

But before we get into all that, we start with some important background.

Background: Number of Houses in Cambridgeshire to Double by 2050

The EWR project forms part of Whitehall’s OxCam ARC initiative as set out in their National Infrastructure Commission (NIC) report^[2] and confirmed in the recent OxCam Spatial Framework 2021 from the Ministry of Housing, Communities and Local Government (MHCLG)^[3]. The NIC report (p.28) envisages building 1 million homes in the Arc between now and 2050 and in particular 271,000 in an area approximating to Cambridgeshire. 

Since the area in the NIC report is not the same as the county of Cambridgeshire the percentage increase between the baseline date of 2014 and 2050 is harder to estimate from publicly available figures, however and Oxford Professor David Rogers has stated that it represents an 81% increase. The recent rate of housing growth will soon have to double to make that target by 2050. 

The average home in the UK generates over 50 tonnes of CO₂ in construction and emits a further 2.7 tonnes per year^[4].  That’s 26.7 million tonnes of CO₂ between 2014 and 2050 for construction and a rate of emission of 0.73 million tonnes / year after 2050 excluding any further construction. We cannot go on like this.

The population of the UK is forecast to grow by 16% by 2050 with the addition of 3 million homes. Therefore, the 1 million homes in the Arc is one third of the number for the whole UK and is concentrated in just 4.7% of the UK’s land area. The NIC report refers to this  “transformational” growth, way beyond anything needed to serve existing residents. We will be transformed into an urban sprawl from Oxford to Cambridge – see Figure 1. Who does this benefit? Not local residents. I suggest that local politicians consider who they are elected to represent. We do not want this.

The OxCam Arc plan is for Cambridgeshire to grow much, much faster than the UK average. The OxCam Spatial Framework plans to create 1.1 million new jobs. We are talking about a lot of people moving into the area. Everyone should be interested in the environmental impact of this and we recommend watching the talk given to the Friends of the Cam recently by the Oxford Professor of Ecology David Rogers who provided many of the insights above.^[5]

Our local environment and residents are in for some cruel and unusual punishment if the OxCam Arc goes ahead and EWR Co.’s project is a core part of it.

Yes, we need more houses and we need better transport for local commuters, but the plans for the OxCam Arc go way beyond that. Perhaps Whitehall have the scene in Figure 1 in mind for the whole OxCam Arc and Cambridge in particular. How long will even the green belt last?

Incidentally, how can anyone plan, propose, decide or even comment on the route of the railway when there is no plan for where these 271,000 additional houses are to be built?

Why talk about this in the context of a post about ‘low Impact design for railways’? Well, most of the Cambridge Approaches material is working on the premise that the EWR Central Section does have a sensible triple (profit, people, planet) bottom line case and, given that it will be built, we are looking at where might be the most sensible place for it to go based on available information. Put another way, we are addressing the proposition in front of us. However, we will just make two points.

• If there is a business case for the Bedford to Cambridge section it will be predicated on this massive housing growth and EWR Co. are therefore in no position at all to take the any moral high ground on CO₂ emissions.
• To encourage all these people to want to work in the area the railway needs to be attractive as specified in the Sponsors Requirements^[6]. The Great Wall, huge grade separated junctions and lots of 4-tracking in Cambridge are an appalling start on this.

Railway Engineering Structures – A Survey of the Options for Low Impact Design

Level crossings are no longer being built for safety reasons, so we are left with some of the more difficult choices in Table 1 above. EWR Co. have proposed a route involving long embankments, viaducts and rail-over-rail grade-separated junctions as part of the extensive 4-tracking as the new railway approaches Cambridge from the south or the north. As can be seen from Table 1, these are some of the structures with the most adverse impact from an environmental point of view. So why are EWR Co. proposing them?

EWR Co. have expressed concern about crossing flood plains and cite a recent landslide in Scotland as a reason to avoid them where possible. We assume that they are talking about the Stonehaven derailment in Aberdeenshire.^[7] This occurred in severe weather near a river crossing in quite hilly terrain where the land slipped. Landslips are often triggered by inadequately maintained drains. The flood plains to the north and south of Cambridge are in flat terrain and there are no river crossings on the northern approach proposed by CBRR. So, we fail to see the relevance of this incident to the Cambridge approaches. It would perhaps be more relevant to the Cam-crossing south of Harston as EWR Co.’s proposed route emerges from Chapel Hill and crosses the river on a high viaduct and embankment.

Towards the bottom of Table 1 we see trench railways as a low impact solution. However, EWR Co. have concerns about these. We address their concerns in Table 2.

EWR Co.’s Analysis of the Northern Approach

EWR Co. flag that “A northern route would cross the newly upgraded A14 trunk road to the west of Girton, which at this location is an eight-lane dual carriageway. This would therefore require a substantial bridge structure. The prevailing low-lying land level mean that this structure would be a prominent feature in the surrounding landscape” see Technical Report Appendix F §1.1.4.

In §1.1.5 of the same report they go on to say: “An additional station could be provided at Northstowe, but the area is low-lying and forms part of a floodplain so the station and its approaches would necessarily be elevated. A junction with the existing West Anglian Main Line (WAML) would be located north of Milton and this too sits in a floodplain.”

As previously discussed they immediately assume that rail goes over road and flood plains need embankments. CBRR’s hugely experienced consulting engineers do not make any such assumptions.

CBRR’s Fen Crossing Proposal for the Northern Approach

In 2018, CBRR published some preliminary alignment notes for CBRR’s proposed route. After discussion with EWR Co. during 2018, CBRR revised their notes^[8]. The route proposal included a Fen Crossing section involving a trench railway so that, where necessary, the railway can have low impact as set out in Table 1.

To quote from their notes. For Map 6 “The highest ground along the route is north of Bourn Airfield where it is about +70mOD, and the line will need a cutting to limit the height to +65m. East of the station it leaves the A421/A428 alignment and drops steadily while heading north east to the east of Dry Drayton and passing below the A14 near the Cambridge Crematorium. By crossing below the A14 the impact on the crematorium will be reduced.”

For Maps 7 & 8 we find the following notes: “North-east of the A14 the line passes to the south-east of Oakington, where a station is proposed to serve Oakington and Northstowe. It then has to cross the fens for about 9km before joining the Cambridge – Ely line. For the fen crossing it is proposed to once again lower the alignment to below existing ground level and contain the line in a structural trench with walls up to flood protection level. This allows it to pass below the Oakington – Girton road, the guided busway, B1049 north of Histon, Landbeach road, and the A10 north of Milton. The advantages of keeping the line low are the reduced visual impact, the ease of building over-bridges, and the avoidance of new embankments which would cause continuing settlement for years after construction.”

EWR Co. have clearly missed the option of rail under road and trench railways in their write up of the northern approach, but they do follow the same route as CBRR in their analysis of the northern approach^[9].  They have also completely missed it for the southern approach. In terms of structures the only options they consider are embankments, viaducts and overbridges. They then conclude, correctly, that these have higher visual impact as we have said in Table 1.

It seems that EWR Co.’s analysis has missed an opportunity to reduce the environmental impact of the railway and this has led them to produce hideous proposals for approaches both northern and southern. One of their reasons to reject the northern approach is the hideous nature of their own design. This is completely invalid.

To get an initial impression of what the design of a trench railway would look like in context it is perhaps best to look at this fly-through of an Oakington / Northstowe Station as proposed by CBRR. 

Notice that right at the end of the video, it is practically impossible to see any evidence of the station. This fly-through has been created by a local game designer based on engineering drawings from CBRR.

Northstowe Station

EWR Co., misleadingly, describe the access to the proposed Northstowe station as follows: “The proposed station at Oakington for Northstowe is at the very southern end of the new town, south of Oakington village, nearly 5km away from the northern edge of Northstowe (roughly a one hour walk).” 

It is also worth seeing this in the context of Homes England’s plans for Northstowe when fully built out as we assume it would be when the EWR services would start in 2030 (see Figure 2).  We agree with EWR that the current settlement of Northstowe is some way from Oakington, but this rather misses the point that only 7% of the housing has currently been completed and that happens to be at the other end of the new town (Phase 1 in Figure 2). When fully built with phase 2 and phase 3, it will reach all the way to Oakington. We also point out that there are other ways to travel 5km than walking. Why don’t EWR Co. say this? 

Although the Sponsors requirements ask for a commuter railway and the EWR Co. traffic model says that 70% of journeys will be local, EWR Co. are proposing a solution which will serve very few people in the area at least initially. It’s for people that live in Cambourne and happen to work at the Biomedical Campus or central Cambridge. How many is that? There are other ways to meet that demand.

EWR Co. also point out that that Northstowe already has the guided busway and imply that it does not need any more public transport provision.

Note that the busway shown in Figure 2 has two stops. During a visit on the 11^th May 2021 we found this sign (see Figure 3) at the Longstanton stop to the north of the plan in Figure 2 and repeated on the front of the buses. Passenger numbers are reduced due to the pandemic and some social distancing is required on the buses, but Stagecoach are using all their buses and there is a currently a capacity shortage. We understand from bus users that the Cambridge buses are already full before they get to the Longstanton stop and this has been the case for years.

We then visited the Oakington stop at around 11am the first Cambridge-bound bus to arrive displayed a “bus full” sign and did not stop. Here is a video of it passing through. Also we could only find two car parking spaces at Oakington Station.

EWR Co. may have spoken to Cambridgeshire County Council about future plans for the busway, but they should realise that these plans are now the responsibility of the Mayor of the Peterborough and Cambridgeshire Combined Authority not of the County Council. Why don’t EWR Co. know this? Furthermore, the new Mayor has dropped the Cambridge Autonomous Metro. This means that the roadmap for the busway is in a state of flux.

What will the situation be like in 2050 if 271,000 more houses have been built in the Cambridgeshire area?

CBRR Trench Design

CBRR are proposing a particular design for their structural trench which makes it suitable for use in low lying areas in flood plains. Figure 4 shows a cross-section of this trench.

The main features are as follows:

• Trains run in a trench of neutral buoyancy so most of the time it neither tries to float or sink
• Flood walls on either side
• Inverted siphons to allow any flood waters to pass beneath the railway line
• ‘Green’ crossings about every 500m for any roads, PROWs or agricultural access

Trench Railways around the world

The designers of the CBRR proposal used a similar approach for the design of a section of the HS1 link near Dagenham which has since been implemented (see Figure 5)

The technique is used for the San Gabriel railway near Los Angeles in a place where there is an earthquake risk and where it won a Californian design award in 2019 (see Figure 6). The currently proposed central section of East West Railway does not look like it is about to win a design award.

The high-speed line between Brussels and Amsterdam also uses the same idea (see Figure 7). See for example this stretch on the approaches to a tidal river called Dordrecht Kil. As with the CBRR approach, the railway goes underneath. Note the water in the ditches on either side of the line – this is a really low-lying area. Dutch engineers know a thing or two about working in flood plains. EWR Co. imply that the precious green belt approaches to Cambridge do not warrant such a low impact design. Perhaps in Holland the government values the environment more than EWR Co. appear to.

Comparison of a Trench and an Embankment

In our previous post relating to the embankments of EWR Co.’s proposed Great Wall, we described the likely dimensions of such structures.

It is perhaps worth comparing the scale of the two side by side to show their cross sections.

This is shown in Figure 8 above. The trench is narrow, reducing land-take and facilitating crossings. It is also deep enough to hide the 4m high trains and any overhead line equipment. The embankment is just the opposite, and may even be worse if it needs a noise barrier on top. 

We talked about land-take in our earlier post about farming, but these embankments would be much worse due to the direct land-take and the difficulty of getting across them. We have spoken a local farmer who told us that his family had worked and developed their farm for 5 generations, but if this happened, it would all be over.

Other farmers have been estimating the effective loss of farm land due to uneconomically sized and shaped plots left by cutting fields indiscriminately. The land that would fall directly under the embankments are a small part of the total lost. The ease of crossing trenches is really important to farming. 

Conclusion

We have set out a variety of railway structures and ranked them in order of their impact from high to low. EWR Co. have proposed using high impact techniques for both their southern and northern approaches through the Cambridge green belt as though there was no alternative and to hideous effect.

During the current consultation, EWR Co. have objected to the use of low impact railway designs at all on the grounds of CO₂ emissions associated with their construction. They have not compared it with their own high impact proposals on those grounds. Nor have they even mentioned them in their analysis despite them having been published by CBRR for use where necessary and for all to see in 2018. 

Their comments seem to indicate a disrespect for the environment and for local residents. This is a shame on multiple levels, not least since we presume that one of the objectives of the OxCam Arc is to create an area will people will actually want to live. 

The fact that EWR Co. CEO Simon Blanchflower speaking on Radio Cambridgeshire recently said that he would not want the railway coming near the village where he lives, speaks volumes. It can be compared to the moment in 1992 when Gerald Ratner described one of his companies’ jewellery products as ‘crap’. This led to severe damage to Ratners’ business. But what will happen to the state-owned monopoly EWR Co.? How unpopular do their proposals have to be to have any effect?

We have presented some background to set the railway construction in the context of the OxCam Arc and its toxic assumption that a million homes will be constructed by 2050. This is so that the attempt by EWR Co. to take the moral high ground on climate change can be seen in context. If there is a case for the EWR, it is as part of the OxCam Arc with all that that entails.

CBRR’s experienced engineers have shown how where necessary, low impact design techniques can be applied to the northern approach. Although not described in this article a lot more could be done with a southern approach to reduce the impact with trenches, tunnels and putting the railway under roads, railways and rivers. The CBRR design sets the standard that we want to see in the green belt of Cambridge.

^[1] Our approach to Mitigating the Impact of Noise and Vibration in Local Communities, Section entitled Low-impact route alignment.

^[2] “Partnering for Prosperity”, NIC Report 2018.

^[3] Planning for Sustainable Growth in the Oxford Cambridge Arc: An introduction to the Oxford-Cambridge Arc Spatial FrameworkFebruary 2021

^[4] What is the carbon footprint of a house?

^[5] The Oxford-Cambridge Arc; An Environmental Catastrophe – Professor David  Rogers. 30 April 2021

^[6] Making Meaningful Connections Technical Report Appendix A §1.2

^[7] Stonehaven Derailment August 2020

^[8] CBRR Preliminary Alignment Notes May 2018, revised Sept 2018

^[9] Making Meaningful Connections, Technical Report Appendix F

Background

EWR Co’s Appendix F to the Technical Report contains two tables comparing the northern approach into Cambridge with the southern approach using a variety of parameters. They include such factors as length of viaducts, impact on residential areas, number of bridges required and impacts on environmental sites such as SSSIs and scheduled monuments. Cambridge Approaches has carried out a similar exercise months before East West Rail and presented the conclusions to the press, to EWR and to the rail minister. The tables from EWR Co are in response to our work. Now that we have confirmation of the route and the results of EWR Co analysis we have updated our assessment as shown in this post to show what we believe is a fairer comparison between the routes.

EWR Co presented their comparison tables to local councillors on the opening day of the of the consultation with a table entitled “actual facts”. We are not sure if this is a reference to a belief that CA analysis is wrong or whether they mean that the rest of their consultation does not contain “actual facts”. Perhaps they can clarify.

Our results very clearly contradict EWR Co claims of an advantage for the southern route. In most cases the total reverse is true. For the few remaining counts, the result is broadly balanced. The main reasons for the difference in conclusions are what factors EWR Co have decided to measure, the assumptions they have made and how they have chosen to measure their figures.

Assumptions and Measurement Points

One important assumption that EWR Co have used to underpin their case is that the West Anglia Main Line (WAML) would require to be 4-tracked (increasing the 2 existing tracks to 4) from where a northern approach would join the WAML at Milton and Cambridge. We believe that this would not need be carried out and we will explain our thinking on this in another post. As a result, we have, for some items, provided two counts – one with the 4-tracking (for direct comparison with EWR Co’s own figures) and one without 4-tracking (which we believe is more realistic).

We have also, in some cases, used two measuring points to gain a more accurate assessment of the factors. EWR Co have consistently used only Cambridge station as the basis for comparison between approaches. This may be reasonable for passenger trains but for freight trains, Coldham’s Common is more appropriate since that is the point where freight trains from the two approaches diverge. A freight train is generally accepted to be noisier than an electrified passenger train and just because EWR Co. will not be operating the freight train themselves, it does not mean that the noise will not wake residents in the middle of the night. A map of the area is shown in Figure 1.

EWR Co have said that they have combined the two northern approach options (i.e. freight passing via a new chord just south of Ely and freight passing via a new chord on Coldham’s Common). They have, notably, omitted to mention any of the advantages of the former option in their comparison of factual data. In particular, there would be no impact of freight on Cambridge residents if our first option were adopted and much less overall. For clarity in comparison of numbers, we have used the Coldham’s Common chord option for measurements.

Results

Analysis

General factors

Operational length

EWR Co recognise that there is little difference (1.1km) between the track lengths of the two approaches for passenger trains measured to Cambridge station. However, the northern approach is over 3km shorter for freight using the Coldham’s Common chord.

Length of infrastructure

While the northern route passes through a greater length of flood zone, it plays this to its advantage by adoption of a trench solution which utilises the buoyancy effect in the waterlogged ground. This results in no viaducts and minimal embankments. It passes beneath roads and the guided busway and could be constructed while keeping the road traffic and guided buses operational. Oddly, when making the comparison, EWR Co have used a similar route to CBRR but, instead of using the CBRR trench construction methodology, they have taken an embankment solution and then proceeded to criticise it. The southern approach has a combined length of over 5km of embankment exceeding 8m in height. The trench approach has been presented on the CBRR website since 2018, so it is strange that EWR Co. do not even comment on it. Did they just miss it? Do they disagree with this widely used approach or are they just looking for reasons to justify a political decision made in favour of the southern approach and find this to be an inconvenient truth?

Impact on residents

This is one of the most important factors between a northern and southern approach, particularly in respect of noise. Night-time noise is clearly more problematic than day-time noise, so we believe that measures appropriate for freight services are more relevant than for passenger services. Although EWR Co have used a variety of assessments, including the length of railway in Cambridge wards, the most direct measure of this is the count of residential properties within 200m either side of the track. The length of track in Cambridge wards is not a very meaningful measurement because in some places the line passes through residential areas and in other places it does not. They have used Cambridge station as the basis for measurements: this is only appropriate for passenger services. We have also considered Coldham’s Common as a basis – see section above on ‘Assumptions and measuring points’. Our figures (which have been assessed by three separate people) are considerably less than those obtained by EWR. However, the absolute numbers are not critical for a comparison – it is the relative numbers between the northern and southern approach that matters. For passenger services the count is similar (slightly in favour of a southern approach) but the critical night-time freight measurement is massively in favour of a northern approach by a factor of over 8:1 (i.e. there are more than 8 times the number of residential properties within 200m of the track on a southern approach than a northern approach).

Roads and other crossings

The number of road and other crossings significantly impacts the overall construction cost of a railway. The greater the span of a bridge, the greater the cost so major road crossings affect the cost more than those for minor roads and farm-tracks. Assuming that 4-tracking will not be undertaken for whichever option is chosen, the overall result is in favour of a northern approach with slightly fewer A- and minor road crossings required. A more significant difference between the approaches is that because the northern approach would pass beneath existing roads, this would result in less temporary traffic disruption during construction and lower noise and visual impacts because of the trench technology.

Environmental factors

Measuring distances to environmental sites cannot reveal the whole picture of the impact of the railway on a site. This would partly depend on the wildlife or ecology that the site is trying to protect. For example, the railway following a southern approach can cause a lot of damage to the Wimpole and Eversden Woods SAC but this is not revealed by the measure EWR Co use to show the impact. Although we have compared the approaches using the same measures as EWR Co, they still need to be considered with some degree of caution.

SSSIs

There are 4 SSSIs within a 2km buffer of the southern approach but none on the northern approach. EWR Co have mistakenly measured the northern approach as having 1 within this distance. The one they counted was probably Madingley Woods which is about 2.3km from the northern route.

SACs

There are no Special Areas of Conservation (SACs) within any of the buffers used by EWR Co. This does not demonstrate the impact of the Southern Approach on the SAC at Wimpole and Eversden Wood in which a colony of Barbastelle bats roost. The bats forage for around 5-7km from the roosting site and would not be affected by the Northern route. See our previous post on this subject, the Wimpole/Eversdens SAC is one of only Barbastelle SACs in the UK and it is in great danger from EWR Co.’s cavalier assertions about mitigation techniques that have failed in the past and would fail here again

Scheduled monuments

The southern route impacts directly (within about 10m) on 3 scheduled monuments whereas there would be no direct impact with a northern approach. Even using a 2km buffer, the southern route fares worse.

Listed buildings

As for other environmental counts, EWR Co have measured two distances from listed buildings to assess the impact of each approach: 10m and 2km, and only using Cambridge station as the measuring point. We consider this to be misleading and have counted listed buildings within three different bands, 10m, 200m and 500m for both passenger trains and freight trains. While EWR Co’s assessment shows broadly similar impacts of both approaches (with a slight disadvantage for the northern route for grade 1 & 2* buildings), our more nuanced and thorough evaluation shows a clear and significant advantage for a northern route, even when considering passenger trains. As mentioned earlier, using Coldham’s Common as a basis for assessment is appropriate for freight trains which cause by far the bulk of noise and air pollution impact on all types of residential property. On this basis, our figures demonstrate that there are more than double the number of grade 1 and 2* properties within 500m of the track on a southern route than on a northern route. The difference is even more stark for grade 2 properties with over 4 times the number within 500m.

Priority habitats

EWR Co have counted the number of priority habitats within 10m and 2km of the alignments. This presentation fails to take account of the size of each habitat. To address this omission, we have considered the length of a 200m zone passing through each site[WH1] , as shown schematically below.

Figure 2 Measurement of priority habitats

Although imperfect, it is considered more accurate than EWR Co’s measure. EWR Co’s assessment results in broadly similar outcomes. However, our measure shows the southern route has about a 2.5 times greater impact than the northern route.

Wildlife Trust sites

There is an advantage of the northern route over a southern route (1 site compared to 2 sites within 2km of the routes) but, because the total numbers are low and the 2km distance is great, this is not a differentiating measure.

Local Nature reserves

Our figures are much lower than EWR Co’s figures for both alternatives so it is likely we have not been able to access all the data that EWR Co have used. But taking EWR Co’s numbers at face value, there is a nominal difference slightly in favour of a southern option (12 sites for a northern approach and 10 sites for a southern approach). Again, this is not a differentiating measure.

Residential properties

EWR Co include commercial as well as residential properties in their assessment, whereas we have considered only residential properties. As previously mentioned, they have also assumed that the West Anglia Main Line (Cambridge to Ely line) will be 4-tracked but without providing any supporting evidence. We dispute this assumption and consider that it could be left as a twin track line. Putting this argument to one side, we have looked in detail at EWR Co’s figures. We count 33 residential properties within 10m of the line that could be impacted by a northern approach with 4 tracks between Milton and Cambridge. This compares to 39 for a southern approach. EWR Co, on the other hand, count 40-85 residential and commercial properties close to the line for a northern route and just 5 for a southern route. We have measured to the boundary of a property. While we do not correlate these figures directly with the requirement for demolition, we consider that EWR Co have made some errors in their assessment. For example, there would be about 11 properties that would be directly impacted on just one site at Highfields Caldecote (the Linden development) on a southern approach.

Conclusions

The overwhelming message from our analysis is that on the vast majority of measures, the northern approach is superior to the southern approach, including embankments, residential impact, road crossings and environmental aspects. For the remaining factors, there is a broad similarity between approaches. The measure that EWR Co have ‘afforded particular weight in the back-check undertaken’, the impacts on residential properties, is broadly similar in our assessment even using the doubtful assumption that the northern route will need some 4-tracking.

We made an initial assessment of the Great Wall in our previous post on the subject. We have now had time to look at the proposal in a bit more detail and this post presents more of our analysis.

Height Profile and Distribution

The structure we describe varies in height along its length and also switches between being an embankment, a viaduct and a cutting. EWR Co. are picking statistics about The Great Wall which may make it seem smaller than it actually is. For example, some of it is at ground level (not much, but some). As it is not one continuous type of structure, the length of each individual section of embankment, viaduct or cutting obviously has a limited length. But one thing is clear: the length of the entire structure from Cambourne North Station to Hauxton junction is 17.4km. As you enter a cutting from an embankment, yes there will be a point where the level difference between the track and the local ground level is zero.

We prefer to present the data in a form that makes it easier to understand.

Figure 2 shows the height above local ground level in metres versus the distance along the track or “chainage” starting at EWRCo.’s proposed Cambourne North Station and ending at their proposed Hauxton Junction. The height is above 4m for 12 km out of the 17.4km from Cambourne north to Hauxton Junction. But the line is particularly high near houses in Highfields Caldecote, Little Eversden, Harlton, the two approaches to Haslingfield and wrapped around the south and east of Harston. 

Figure 3 shows the distribution of heights of the structure above local ground level. Specifically, it shows the length of track above a threshold level. For example, looking at figure 3, there would be just over 6km above a height of 8m.

Leaving out any overhead line equipment, trains are around 4m high. So, with a 4m high embankment or viaduct, it would be possible to see the top of a train above the 8m rooftop of a 2-storey house. 

Embankment Cross Section

CBRR have produced a cross-section of what a 10-metre high embankment would look like (see Figure 4).

The tracks are on a 10m wide platform. To reduce noise impact, we would expect acoustic barriers on either side of the track.  If we are lucky enough to get an electrified line then the Overhead Line Equipment (OLE) would be on top. Remember also that in most of this section the trains will be travelling at up to 100 mph.

Either side there would be slopes, usually at an incline of 1:3, making the width of a 10m high embankment 70m. These slopes would be too steep to be returned to farming. There would be security fences on either side of the embankment and culverts every so often to allow the passage of wildlife and people. 

Consider the school children making their way to Comberton Village College from The Eversdens. Will they divert and cycle down the busy A603? Will they pass through a 70m culvert on dark December afternoons? Will they get through the security fence and cross the tracks? There could be similar issues for young children from Newton to Harston primary school or from Harlton to Haslingfield primary school if there is no safe way to get across the Great Wall.

Much of the route will be on clay and a significant foundation will be necessary with piles beneath it to reduce settlement as shown in Figure 4. Consider the carbon emissions required to make these large structures and carry in the material to do so. The material from the destruction of Chapel and Money hills will not be enough.

Land Take

We have estimated that the total area of land required in this 17.4km section, taking viaducts to be just 10m wide and embankments and cuttings with 1:3 slopes. The width of the embankments can be calculated from their height profile and a 3m width allowance for security fences on either side. The result is an estimated 206.3 acres of land taken by this structure excluding any construction or maintenance roads on either side.

It would be interesting to get an estimate of the weight of material that would need to be transported to make these embankments.

As previously explained the farmland to the south of Cambridge is particularly important for food security when climate change induced sea level rises are considered. The author of that article has estimated that 44.5 acres of his land near Harlton will either be directly lost or become unfarmable – and that is just one farm. The effective land take is likely to be much-much higher than 206 acres. This is farmland that has been cultivated for generation after generation.

Before you reach the conclusion that it would be the same to the north – please consider the trench railway technology proposed by CBRR for the fen-crossing section of their proposal and their proposal is low in the landscape all the way from Cambourne North station into Cambridge.

Viaducts

We can get an idea of what a modern railway viaduct will look like from the recently constructed Hitchin Flyover (See figure 5). But bear in mind this is only 5m high and single track.

Composite Photograph of Highfields Caldecote

An Impression of the Environmental Impact

This post has so far focussed on the facts about the proposed Great Wall. We shared something about how we feel about it here and here.

Local residents Anna and Tom have prepared a video entitled “Muted By Covid” which shows part of the section of the proposed route between Harlton and Haslingfield on the ground.

The Northern Approach to Cambridge in the EWR Co. 2021 Consultation

In the light of their emerging preference for a route with a station to the north of Cambourne, EWR Co. have correctly decided to reconsider the northern approach to Cambridge. Their high-level assessment of the northern approach is presented in Appendix F of the Technical Document from page 44 onwards. In this post we focus on the top-level points paragraph-by paragraph that they make in section 1 of Appendix F. The EWR Co. text is repeated in italics for convenience.

1.1.1 This appendix reviews the potential for EWR to approach Cambridge using a northern alignment between Cambourne and Cambridge via Milton. EWR Co has considered this route in order to verify the decision taken to prefer Route Option E, which approaches Cambridge from the south. This is necessary because route alignments in Section E might serve a station to the north of Cambourne. Such a station could be broadly equidistant by rail from Cambridge station, serving which is an objective for EWR. This appendix considers whether a northern route into Cambridge could satisfy the objectives for the EWR project and the extent to which a northern route compares with the southern alignments considered in Section E, F and G of the Technical Report. 

EWR Co. correctly say that a station at Cambourne North would be broadly equidistant from Cambridge Station with a southern route or a northern route. However, we know that Cambridge is not intended to be the final stop for EWR services; the plan is that it will extend to Norwich via Ely and Ipswich via the Cambridge to Newmarket line.  

EWR Co. do not insist that passenger trains via Bletchley have to go in and out of Milton Keynes, nor do passenger trains from Bicester to Winslow have to go in and out of Aylesbury.  In the same way, passenger trains between Cambourne and Waterbeach do not all have to go in and out of Cambridge. Taking the northern approach the Cambourne Waterbeach link is 12 km shorter than going via the southern route and the three large new towns to the north and west of Cambridge become well connected. 

1.1.2.  The approach to considering this that EWR Co has taken is first to consider if a change in circumstances that could affect the decision not to prioritise northern routes into Cambridge has taken place. It has concluded that routeing via a Cambourne North station is such a change. It has then looked at other new and more detailed factual information available to it in order to establish if the decision would be different had that information been known at the time. To do this, EWR Co has considered a northern route from Cambourne North. 

Cambridge Approaches (CA) have been considering this issue for several months and have used broadly the same southern approach that EWR Co. are now proposing for their preferred alignment 9 in their comparisons. The CA comparisons are presented here and here.

1.1.3.  The selection of a preferred route option in 2020 following the previous public consultation was based on an assessment of how the various options performed against a combination of fifteen Assessment Factors, which included transport user benefits as well as capital and operating costs, and against the overall programme objectives for EWR. The decision to enter Cambridge from the south was based on engineering, operational, economic, and environmental reasons. This appendix considers how a route approaching Cambridge from the north would perform in relation to the same topics. 

The methodology used by EWRCo. in their previous assessment is set out in §5.4 and §5.21 of their Preferred Route Option Report. It is clearly not an exact science, however among the “second set” factors listed in §5.21 and still not correctly addressed in this report are: 

1. “Short distance passenger services and connectivity to support commuting into key employment hubs (current and future)”
2. “Consistency with plans for the location of local settlements”
3. “Satisfying existing and future freight demand (as anticipated by the freight industry) where affordable.”

We make no comment about whether these factors were important for choosing between options A to E, but they are definitely important when choosing the route into Cambridge to the north or south.

There are significant new towns to the north, and a development void to the south. Freight can bypass Cambridge to the north but will have high residential impact to the south. The local transport services to the north would be greatly helped by a northern approach.

1.1.4 In engineering terms, a northern route from Cambourne to Cambridge is feasible, although it would be complex and expensive to consent, construct and operate. A northern route would cross the newly upgraded A14 trunk road to the west of Girton, which at this location is an eight-lane dual carriageway. This would therefore require a substantial bridge structure. The prevailing low-lying land levels mean that this structure would be a prominent feature in the surrounding landscape. 

The idea at the railway would cross the A14 here with a bridge is not the only option. It is surprising that EWR Co. do not mention CBRR’s notes on the preliminary railway alignment.  They would have found that under Map 6 it states “East of the station it leaves the A421/A428 alignment and drops steadily while heading north east to the Dry Drayton and passing below the A14 near the Cambridge Crematorium. By crossing below the A14 the impact on the crematorium will be reduced”. The notes have been available on the CBRR website for years and the impressive CVs of the consulting engineer designers of this route are given at the end of the document. They have designed railways around the world.

It is not only the impact on the crematorium that will be reduced, but also the visual impact on the whole area. In EWRCo.’s statement on mitigating noise and vibration we find the following statement “Sometimes we will need to elevate the track, for instance when trains intersect with roads and cross land in a floodplain. However, where it’s practicable we will consider building the track low in the landscape.”

CBRR based their proposal on the design by one of their engineers which was used on HS1 at the tunnel portal approach structure near Ripple Lane, west of Dagenham: with the trench deep enough, roads crossing the railway need climb no higher than the top of the trench’s flood wall.  CBRR are not the only people proposing, or indeed using, trench railways as a solution for low environmental impact railways including those crossing in flood plains. Consider for example the section of this high-speed railway from Brussels to Amsterdam where the track is in a trench before passing under a tidal river – see Figure 2. It is not clear why EWRCo. have not considered this approach. There are many examples around the world; the San Gabriel trench railway recently won a design award in California. We don’t think that the currently proposed Great Wall is likely to win many design awards. 

1.1.5.  An additional station could be provided to the near Oakington, south-east of Northstowe, but this area is low-lying and forms part of a floodplain so the station and its approaches would necessarily be elevated. A junction with the existing West Anglia Main Line (WAML) would be located north of Milton and this too sits in a floodplain. This location was also granted outline planning permission for the proposed Cambridge Sports lake. 

Firstly, only 700 of the planned 10,000 houses in Northstowe have been built. These additional houses will bring the development right up to Oakington. Why don’t EWR Co. know this?  Why are they talking about people walking for an hour to get to the station? The new town of Northstowe will be the largest new town in England since Milton Keynes and current plans will make it bigger than Ely. It is also likely that in future local plans Northstowe will grow further. The Cambridge Autonomous Metro (CAM) is a possible solution (to supplement the existing, at capacity, guided busway), but it currently lacks funding. Why are EWR Co. referring to the County Council plans to develop the busway – isn’t this now the responsibility of the Combined authority? Why don’t EWR Co. know this?

Secondly, trench railways work in flood plains. Going back to the notes produced by CBRR we find the following under Maps 7 & 8: 

“North-east of the A14 the line passes to the south-east of Oakington, where a station is proposed to serve Oakington and Northstowe. It then has to cross the fens for about 9km before joining the Cambridge – Ely line. For the fen crossing it is proposed to once again lower the alignment to below existing ground level and contain the line in a structural trench with walls up to flood protection level. This allows it to pass below the Oakington – Girton road, the guided busway, B1049 north of Histon, Landbeach Road, and the A10 north of Milton. The advantages of keeping the line low are reduced visual impact, the ease of building over-bridges, and the avoidance of new embankments which would cause continuing settlement for years for years after construction. After crossing the A10 the line bends to the south and rises to the level of the main Cambridge – Ely line which it joins once at the correct level. The line continues south south-west to Cambridge North Station.”

So, the station would not need to be elevated at Oakington. 

Thirdly, why do EWR Co pay such attention to the proposed sporting lake at Milton? It did not have planning permission or funding at the time it was mentioned in Chapter 16 of the Preferred Route Option Report in January 2020. It does not have either now. If it did get planning permission then the railway could slide underneath it in a trench as proposed by CBRR in Map 8b of their notes on the preliminary railway assessment.

1.1.6.  The route into Cambridge would be via the WAML, a two-track line which would need to be upgraded to a four-track line to accommodate the additional EWR services. The WAML corridor between Milton and Cambridge is much more constrained than a southern approach with properties against the railway boundary and multiple highway crossings with adjacent properties. This would necessarily require demolition of residential and commercial property and the widening or replacement of several substantial structures, including the A14 bridge at Milton, and a new bridge over the River Cam. Cambridge North station would also need to be modified to accommodate the additional lines. In addition, the road bridges carrying the A1303 Newmarket Road, Coldhams Lane and Mill Road in Cambridge would all need to be replaced and widened to accommodate the extra tracks. 

EWR Co. assert that the WAML would need to be 4-tracked. This would clearly be a significant project, comparable in scale to the 4-tracking required from Shepreth Branch Junction to Cambridge Station with the southern approach. But where is the evidence that the 4-tracking is required?

It is up to EWRCo. to fully present their justification of this important assertion. In doing so they should consider the following:

1. Is the opportunity being missed to rationalise the many independent rail services that will all be passing between Cambridge South, Cambridge and Cambridge North stations in 2030, especially in the light of the demise of rail franchises? We count 7 different passenger services at the moment, without EWR Co.
2. Britain is already changing from line-side signalling to in-cab signalling. This allows signallers to talk to trains continuously rather than only at fixed points. This will vastly improve line capacity. Thameslink through central London was planned to allow 24 trains per hour rather than the usual rule of thumb of 10 trains per hour. EWR Co. are specifying this in cab signalling for their new trains.
3. Does the benefit of the 4 tph clock-face timetable really outweigh the costs of creating more tracks through Cambridge [and presumably other cities along the EWR]? If this feature triggers 4-tracking,EWR Co. should consider waiting for better signalling before introducing it.
4. With a southern approach to Cambridge and EWR Co.’s current assumptions about 4-tracking to the north of Cambridge, will the 4-tracking from Cambridge to Milton not be necessary anyway for extending EWR’s services further east – or is this considered out of scope? That would be short sighted and would not meet the Sponsor’s Requirements (Technical Report Appendix A §1.6)
5. Given the uncertainties on passenger demand does it make sense to commit to extra tracks through Cambridge for this project? Anthony Browne MP expects that post Covid, people will continue to work at home 2 days per week leading to a 40% reduction in passenger demand long-term.
6. Much play is made of a detailed assessment of the property acquisitions that would be needed with the “NA2” section into Cambridge.  Although the southern approach is EWR Co.’s preferred route, the assessment does not go into as much detail about the property acquisitions it needs or might need.  It does not, for example, explain what the property acquisition impact might be of EWR Co’s current conclusion that the line does not need additional tracks between the new Harston Junction and the existing Shepreth Junction proves “on further investigation in coming design phases” (paragraph 11.1.2 Technical Report) to be incorrect.  This gives the consultee a biased impression in favour the southern approach. 
7. A similar argument can be made as above for possible bridge work for 4-tracking the Shepreth Branch line on a southern approach. If their future investigation is incorrect, the cost consequences of a possible mistake would be far greater than 4-tracking the NA2 section, with modifications required to bridges including crossings of the M11, the Cam, the Newton Road, the B1368, the road between Little Shelford and Hauxton and the A1301 in Great Shelford.
8. The pre-Covid 2018 baseline rail traffic used in the assessment in Appendix F shows that there is a lot less traffic to the north of Cambridge than to the south. There is a major cost saving opportunity available for this section if NA2 were not to require 4-tracking.
9. Given the overloaded nature of Cambridge Station identified above and the need to integrate with local transport schemes EWR Co. should consider having some passengers changing at Cambridge North or South onto existing services (or the CAM, which is proposing to link the three railway stations) rather than adding to the congestion at Cambridge Station. If London allowed all trains to pass directly through or go straight into the centre, the central district would be nothing but railways. It is reported that nearly 12 million passengers per year use Cambridge Station (with over half a million interchanges) while less than 1 million use Cambridge North (with less than 2,000 interchanges). Is the solution really to expand Cambridge Station?
10. If EWR does not take a northern approach, neither the CAM nor EWR is proposing to link Cambourne or towns west of it directly to the northern part of Cambridge.  This seems a major omission, especially as an improved A428 between Black Cat and Caxton Gibbet) may encourage people to drive this route.
11. Transport now accounts for 40% of the UK carbon budget and after the coal-fired power stations have been closed down, future carbon targets will press further on transport construction.  Are unnecessary works in 4-tracking Cambridge really justified and when will EWRCo. publish their carbon assessment?

1.1.7.  Economically and operationally, a northern approach to Cambridge does not provide the same level of benefits as a southern approach and is less able to satisfy the overall objectives of EWR. In comparison with services entering Cambridge from the south, which in all our assessments are assumed to call at the new Cambridge South station that is being developed to serve the heart of Cambridge’s internationally significant Life Sciences cluster in the south of the city en route, the Northern approach would be slower and more complicated. This is because, using assumptions common to both scenarios, if the EWR services entered Cambridge from the north they would need to pass through Cambridge station in order to then turn back at the new Cambridge South station, which would need to be modified. 

§1.1.7 contains more assertions without supporting evidence. Figure 4 is a map from a Cambridgeshire County Council prepared in connection with the Greater Cambridge Local Plan showing the many major employment sites around Cambridge. It is clear from the map that there are many more employment areas served by a northerly approach than one from the south. The Addenbrooke’s / Biomedical Campus site is number 26 on the map and, independently of the EWR Co. project, will be served by Network Rail’s Cambridge South Station. Cambridge is blessed with internationally significant companies in its Science Parks near to Cambridge North Station (ask yourself why that station was built before Cambridge South).

If not serving Cambridge South directly is a problem, isn’t not serving Cambridge North directly equally a problem? If EWR does go on to serve Cambridge North – as suggested in §1.1.10 (quoted below) – EWRCo. need to explain why this will not trigger a 4-tracking requirement.

On closer examination the argument in §1.1.7 is not a distinguishing assessment factor.

1.1.8.  Furthermore, services on a northern approach utilising the EWR lines to travel further east to Norwich and Ipswich could not do so without reversing manoeuvres at Cambridge station and without the construction of further infrastructure to enable these onward journeys. This would add time to journeys and increase operational complexity. To travel eastwards from the north, without calling at Cambridge station and therefore avoiding the reversing move, a new railway chord would need to be constructed at Coldham’s Common or Ely. This would not meet the Project Objectives as Cambridge station would not be called at. However, future freight on the Newmarket Line could use the chord to avoid Cambridge station. Furthermore, although the length of railway for a northern route and southern alignments is similar (the northern route is approximately 600m longer) journeys approaching Cambridge station from the north would take longer due to any extra time spent at a stop the new Oakington station for Northstowe station. If this intermediate station is omitted, then journey times would be approximately the same as for services approaching from the south. 

In researching the rail passenger services currently passing through Cambridge to the north we notice that there is an hourly service from Birmingham and another from Norwich. Both of these services terminate at Stansted airport. There is clearly significant demand to get to Stansted and it is reasonable to assume that this market demand would also be there for EWR passengers. With the southern approach, passengers would either have to change at Cambridge [South] to get to Stansted or EWR trains would have to reverse out to get there. This is not the case for a northern approach. Why is this situation materially different from these points about Norwich?

The services provided in the Project Objectives should be demonstrated to prove they meet market demands: rigid control of projects from central government does not have a great track record of producing what customers actually want[1] . EWR Co. should publish more results from their transport model, which we understand to their surprise show that 70% of the demand is for local trips. (see East West Railway Project Update 2 December 2020).

If the demand is mostly local, it is surprising, to say the least, that adding a stop at Northstowe, the largest new town in England since Milton Keynes (and one which only has an already overloaded[2]  guided busway) does not benefit the business case for the railway. A stop a Northstowe would greatly benefit employment throughout Cambridge, allowing people living in more affordable housing to travel easily to their places of work. If it is true, perhaps all stations except Oxford and Cambridge should be removed so that the projected 18,000 end-to-end journeys per year can be served uninterrupted. But that would be less than one person per train. 

While on the subject of Milton Keynes, it is clear that there will be trains between Oxford and Milton Keynes, but not whether there will be trains between Milton Keynes and Cambridge.  It looks as though the link is with Bletchley.  Either that or every train journey between Oxford and Cambridge will reverse from Milton Keynes back to Bletchley. Perhaps EWR Co. could clear that one up.

EWR Co. please publish more of the transport model – and the business case.

1.1.10.  Although stopping at Cambridge North would connect existing and planned employment sites and housing to the route, a northern approach forgoes the opportunity to directly connect the new Cambridge South station, and planned growth around it, to the route with fast, reliable east-west public transport. A southern approach is better aligned with the local and national economic and strategic ambition to support Cambridge’s internationally significant Life Sciences cluster. In addition, it would be possible for services approaching Cambridge from the south to continue beyond Cambridge station and serve Cambridge North if required. 

Please provide a reference to the local and national economic and strategic ambition to support Cambridge’s internationally significant Life Sciences cluster over and above other high-tech sectors in Cambridge. Also, please explain why many of the sites in the Life Sciences cluster that are not located in vicinity of Cambridge South are less important? Consider for example this set of life sciences companies on the Cambridge Science Park.

Of course, it is beneficial for the EWR to serve Cambridge North directly and, as previously mentioned, this would, by EWR Co.’s logic, trigger 4-tracking on the section of the line to the north of Cambridge Station for a southern approach. This problem is a symptom of the lack of effective integration of the EWR project with local transport projects. Rail passengers going to London do not all expect to get directly to the centre of the city without changing to local transport. Cambridge is starting to show the same problems and the solution is not to add more railway tracks and freight trains through the centre.  It is also a result of the fact that EWR Co’s responsibilities end at Cambridge Station and they don’t look beyond that point unless it suits their argument to do so.

This assessment of the economic impact of the railway on the Cambridge economy might also benefit from closer collaboration with the local experts from Greater Cambridge Shared Planning who do not seem to have been involved in this assessment.  And while EWR Co are speaking to them, they might wish to explain why §2.3.10 appears to be trying to pre-empt decisions on the location of housing growth which are a matter for the relevant local authorities not EWR Co.

1.1.11.  A qualitative assessment of capital costs for a northern route has been completed and the extent and complexity of the structures, poor/wet ground conditions between Oakington and Milton, loss of residential and business properties, and modifications to the railway and existing stations are expected to make this solution more expensive than the southern alignments proposed by EWR Co given that the alignment lengths are similar for each approach. 

We find the idea of a qualitative assessment of capital costs an interesting one.  This assessment is based on the unjustified 4-tracking assumptions we have referred to above. Again, if the EWR is trying to get good connectivity to Cambridge then a solution for all three Cambridge stations and onwards to the east is required.

It also utterly fails to address the issue that the Shepreth Branch line would cost significantly more to 4-track than a northern approach if, as previously mentioned, their track demand assumptions are incorrect for this line. Our studies show that leaving 2-tracks on the SBR places severe constraints on the EWR timetable to say the least.

1.1.12.  The considerations above relate primarily to engineering, operations and economics.

Such a the top-level assessment should also include environmental and residential impacts. Why have EWRCo. still not performed a strategic environmental assessment? (Saying that legally you don’t have to is not a defence). This approach will lead only to mitigation of environmental damage rather than avoiding it in the first place.  The barbastelle bat is one of the UK’s rarest mammals. There are only six known maternity sites in England, including the Wimpole and Eversden Woods, and all are designated as SACs.  The Wimpole and Eversden Woods site is the only one of these sites in Cambridgeshire.  Why do EWR Co think that their impact on it can be mitigated?  There is nothing to support this assumption.

1.1.13.  The route that EWR Co has considered is not designed to the same level of detail as the southern alignments. However, the design level is sufficient to enable a comparison to be made. That design is also sufficient for high level environmental comparisons to be made.

Not entirely true. The assessment of the unjustified 4-tracking to the north is explained in considerably more detail (37 pages, pp. 64-101 in Appendix F)  than the extensive 4-tracking required to the south (4 sparse pages, pp.415-418 in the Technical Report) which concludes with the statement in §11.9.8 “preliminary designs for this section of the Project are being developed and will be introduced as part of a further Statutory Consultation in due course.” We can only conclude that this style of presentation is to exaggerate the case for the southern approach beyond what the facts will sustain.

EWR Co’s statements in their ‘high level environmental comparisons’ are riddled with errors. Examples include EWR Co’s assertion that the N approach would be within 500m of built-up areas of Caldecote, Dry Drayton, Hardwick and Horningsea. In fact, it would pass within about 800m of Caldecote and 1300m of Hardwick. While it is within about 450m of Horningsea, that village is already next to the WAML (and future combined track). EWR Co also talk about impacts on Madingley Hall and the American Cemetery. This is totally misleading – Madingley Hall is about 1.3km away and existing trees would prevent views to the path of the CBRR route. The American Cemetery is 2.4km away and the viewpoint faces a different direction to the CBRR route.

1.1.14.  This appendix demonstrates that an alignment approaching Cambridge from the north remains less attractive than a southern approach into the city, reinforcing the previous conclusion that a southern approach to Cambridge should be preferred and the case for the proposals described in Chapters 9, 10 and 11 of this Technical Report. 

We leave it to the reader to decide whether EWR Co. have done this. Needless to say we do not think so.

If you agree that we are entitled a fair consultation on a northern approach in parity with the southern approach please sign the petition. You will be joining 10,000 others in doing so.