Looking North: The Future of Kings Cross and Moorgate

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The next stop in our random jaunt around the latest RUS is King’s Cross and the line from Finsbury Park to Moorgate. Historically King’s Cross has had to deal with a lot of terminating trains ranging from those arriving from Scotland to local commuter services. It also used to have the “York Road Curve” and the “Hotel Curve” that led to and from the City Widened Lines respectively. This enabled local trains to reach the city and terminate at Moorgate. The northbound Hotel Curve route was served by a steeply-graded platform 16 but the southbound York Road route actually had its own separate station called King’s Cross York Road (some excellent photos can be found in the link) which was situated slightly to the north of the current platform 0. Of course, for most practical purposes, this one-platform station was regarded as part of the main station.

In August 1976 a big project was completed which saw suburban electrification and the roundabout, unsatisfactory diesel-operated route to Moorgate from Finsbury Park replaced by a direct route using the former Northern City line of London Underground. This originally opened in 1904 and had (for the time) unusually large 16 foot diameter tunnels. It was actually built for the purpose of allowing intended electric trains on the Great Northern route to go directly to the city. Perhaps we shouldn’t complain about current timescales, when we realise that this project ultimately took another 72 years to come to fruition. The diversion of suburban traffic away from King’s Cross using this direct new route together with subsequent main-line electrification and the benefits that it brought meant than for many years King’s Cross could function quite adequately using the eight main line platforms and two, subsequently three, suburban platforms.

The Thameslink Programme will now rescue King’s Cross from potential capacity issues on the suburban side, as trains from Peterborough and Cambridge will be able to run to St Pancras low-level using tunnels already built but currently devoid of railway infrastructure. These were constructed a few years ago in advance of the reconstruction of St Pancras International and are a more sensible example of something built but not put into use for its planned purpose until later.

However, running suburban services to St Pancras low-level will do nothing to solve the following issues:
– track capacity north of Finsbury Park
– capacity on the underground Moorgate route which is limited by platform length to 6-car trains
– lack of capacity on the main-line services to Leeds, York and beyond which have tended to experience growth over the years (a trend is expected to continue).

The lack of capacity on the main-line services can be further subdivided into the constraints caused by train length restrictions and those caused by limitations on service frequency. We do not need to worry about insufficient platforms this has not be a significant long-term constraint since platform 0 came into use.

Let’s look at the RUS proposals to address these issues.

Track capacity north of Finsbury Park

When writing for London Reconnections one has to set some kind of limit on how far out of London we report on. The RUS conveniently refers to “London Approaches” so we will limit ourselves to these. In this category it includes the already committed scheme to have six operational passenger-carrying tracks between Finsbury Park and Alexandra Palace. This is a scheme that has been proposed for around for around twenty years, maybe more, but it is only now, particularly with the Thameslink Programme, that the predicted traffic levels mean that the expenditure can be justified. That leaves the Big One – four tracking in the Welywn North Area.

For many years the Digswell Viaduct, around a couple of miles north of Welywn Garden City, was regarded as the limiting constraint on the East Coast Main Line. It is easy to see why people come to this conclusion. It is the first point, as one heads north, that the tracks go down from four to two and later, prior to reaching Knebworth, the next station along, it reverts to four tracks. However to get to Stevenage, the next station beyond that, trains from King’s Cross or Moorgate can take the slower and less direct Hertford loop from King’s Cross so the issue becomes less about overall capacity and more about minimising point-to-point timing. Highly relevant is the fact that the Welwyn tunnels to the north of the viaduct are also on the two track section, so widening the viaduct without tackling the tunnels (totalling about one mile of tunnel) would be of very limited value.

From an operators viewpoint, if there is one thing worse than a two track section on a four track line then, it is a two track section on a four track line with a station on it. Here the station in question is Welwyn North – which has an erratic service in peak hours and only two trains an hour off-peak. The poor service is probably due mainly to the fact that each stopping train occupies a least two train paths on a critical section rather than any lack of passenger demand. The RUS makes it clear that there is no point in tackling the viaduct on its own and concludes “This option cannot be recommended at present due to very high cost and insufficient evidence that it is required. However protection is recommended regarding the land concerned so that it is not impractical later.”

Track Capacity between Moorgate and Finsbury Park

The RUS indicated there would eventually be some capacity problems on the underground branch line to Moorgate. There are currently 12 trains per hour to Moorgate. Some on the Welwyn routes will be diverted into the Thameslink tunnels but these are to be replaced by more trains running from the Hertford loop, leaving overall capacity unaltered. Eventually, however, this will be insufficient. Because the line is underground the more common option of lengthening the trains is not a viable option and so any gap needs to be covered by running more frequent trains.

Increasing the number of Trains Per Hour (tph) on long distance services

There are two suggestions here. One is a revamp of the timetable once certain remedial works at Peterborough and beyond are implemented to increase capacity. This has been a long term objective for some years and has required the completion of a lot of relatively small schemes to alleviate pinch points. This, it is believed, will allow 7tph on alternative hours instead of 6 as at present. The restriction to alternative hours is due to the need to provide more freight capacity further up the line.

The other suggestion is a hope expressed that the ERTMS (European Rail Traffic Management System) – an advanced signalling system to you and me – will allow a service improvement of two more trains per hour in peak times. The RUS acknowledges this would be costly and is unlikely to be able to form the basis of a business case for a number of years given the limited benefits. What it neglects to mention is that the version of ERMTS which would improve capacity is currently really nothing more than a paper specification that no-one yet has managed to successfully implement.

Lengthen Trains on the East Coast Main Line

Readers may be aware that there are times when we get confused. This is one of them. For years this author has understood that the reason trains aren’t longer on the ECML was because the platform at King’s Cross are not long enough – and there has been talk of opening out the Copenhagen tunnels north of the stations throat. In the old days of steam (which necessitated many light engine movements) and the York Road curve, there were six lines into King’s Cross arranged in pairs through three sets of tunnels. With modern signalling and electric stock four tracks are perfectly adequate and the easternmost tunnel has been abandoned. It has often been suggested that if the south portal of the remaining two operational tunnels was opened up then the platforms could be lengthened and longer trains could be run. To this author it seemed likely, therefore, that this idea might feature in the RUS, if only to say it is impractical. However there is no mention of this at all. Instead we have two suggestions. One of them suggests that the length of the platforms is not an issue and the other one suggests it is.

The first suggestion is to reconfigure the current 2 + 9 formation (power car at each end and nine carriages) to a mixture of 2 + 10 and 2 + 8. The idea is that the longer trains would be assigned to the busier services. The operational analysis is that “A mixed fleet would create increased complexity in timetabling and has the potential for small
increases in journey times caused by slower acceleration of longer trains”. Of course this suggestion doesn’t actually increase overall capacity but does add operating complexity. We are open to ideas as to why they didn’t suggest just buying extra carriages (à la Pendolino) and lengthen all the trains. More importantly, this option suggests that the current platform length is not a limiting factor.

The second suggestion is that trains are designed or adapted to carry passengers in the first and last vehicle, which seems a somewhat strange suggestion. For many years the rail regulator of the day has limited passenger carrying in the leading vehicle to trains not capable of exceeding 100 mph, although it is understood that in recent years there has been some relaxation of the rules. Whether a similar restriction has been applied to the trailing vehicle in the past is not immediately clear. This is really a much bigger issue than capacity on the ECML, and even with today’s more compact electrical technology and better sound insulation it might well not be realistic.

More importantly this suggests that platform lengths are an issue. Given that this tends only to be an issue at terminal stations (because there is normally no need for the first or last vehicle to be in the platform at intermediate stations) adding another carriage would have seemed to be the easier option, and if this meant that the platforms needed lengthening then it should be investigated as to whether or this was practical.

Finally something that doesn’t really get a mention when considering King’s Cross is HS2. The RUS tends to take the attitude that considering HS2 up to Birmingham is relevant but beyond that, to places such as Leeds, is really beyond the time frame of this study.

However this RUS leaves the impression that it is there, just lurking in the background. The suggestions for long distance trains are really just short and medium term solutions and there appears to be no major strategy for dealing with growth of long distance traffic at King’s Cross as we approach the middle of the 21st century.

So, in summary, it is believed that all foreseeable growth in suburban traffic can be accommodated but at some point, if railway traffic continues to rise, we really do need a plan to cater for the expected future demand on the East Coast Main Line.

Written by Pedantic of Purley