The RUS: Thameslink Technicals and Hypotheticals

As most readers will know, the Thameslink Programme is a £5.5 billion project to upgrade and expand the the Thameslink service. More accurately, it is the name given to two related projects. One is lead by Network Rail and is a £3.5 billion project to upgrade the stations, track and signalling on this route and the other is a new build of rolling stock led by the DfT. As an RUS piece, this article is obviously about the first of those projects.

As the RUS focuses on schemes that are currently approved, one of the good reasons to search the RUS is to find out more about the plans for Thameslink. Sadly though, although Thameslink is mentioned on numerous occasions, one is not much the wiser at the end of it.

Thameslink has long suffered from information blight. Unlike Crossrail with its excellent website, Thameslink seems to fall between two stools. On the one hand First Capital Connect has an informative website but this is geared at existing customers who may be disrupted by the work being done. Network Rail does provide information on their site but the emphasis is on publicity for the work they do or – to be more accurate – the work they have done. Neither is really much use for finding out what is going to happen.

There is another very valid reason why one cannot find out how Thameslink will look when completed – nobody really knows.

Unlike Crossrail, where the final routes needed to be well defined before proceeding, Thameslink plans merely showed “indicative services” that were sufficient to justify the core scheme. If a subsequent proposal could be shown to be better then there was no reason why a change could not be made during the lifetime of the project.

Indeed, with the scheme virtually becoming a two-stage project (mainly but not entirely due to the Olympics) and the spending review meaning that things post-Olympics will not proceed as fast as originally planned, it seems that there will be a mid-project “pause for breath” whilst the project is re-evaluated and detailed preparations are made.

So what do and don’t we currently know about the Thameslink programme? Well it does seem pretty well established that 24 trains per hour (tph) will run in each direction between Blackfriars and Kings Cross Thameslink. This does seem to be a fundamental part of the scheme and without it much of the benefit is lost. If the capacity were to go down to 20tph then the reality is that eight extra services per hour would have to be found space at mainline termini that simply do not have the capacity for them. Additionally, it would be hard to justify the post-Olympics part of the project on the basis of an extra 4tph – as by December 2011 we should have 16tph (and we already have 15tph although admittedly some of these only go as far as Kentish Town).

It also seems pretty well established that ultimately the objective is to run 12 carriage trains, but this appears to be overstated as it only applies to 14 of those 24tph. It also seems inconceivable that the recently built (but currently unused) tunnels from Kings Cross to the ECML were not used in future, so our routes north of London are pretty well decided.

Indeed the only real issue seems to be whether to go to King’s Lynn as originally planned or to stop at Cambridge. Current thinking seems to be to stop at Cambridge and leave longer distance journeys to and from Kings Lynn as services that terminate at Kings Cross. Rather curiously, in one place the RUS refers to Kings Lynn being served by Kings Cross using “two x eight-car 365 stock” and in another “12-car outer suburban operations (including Thameslink)/IEP on Ely/Kings Lynn”.

Fortunately, however, the RUS details its projections for services north of the river. They are:

– Bedford (MML) eight x 12-car Thameslink stock
– Luton (MML) two x eight-car Thameslink stock
two x 12-car Thameslink stock
– St Albans (MML) four x eight-car Thameslink stock
– Welwyn Garden City (ECML) four x eight-car Thameslink stock
– Peterborough (ECML) two x 12-car Thameslink stock
Cambridge (ECML) two x 12-car Thameslink stock

Now we come to south of the river and this is where we really are in a world of speculation. Take what comes as, what Peter Snow would say on election night, “just for fun”. The RUS gives us hints and clues but we really need to look elsewhere as well.

The one thing we can know for sure is that trains on the Wimbledon loop will no longer be Thameslink trains. Basically, once it was decided to put the through platforms at Blackfriars on the eastern side, these services were doomed due to potential pathing problems. In the overall scheme of things this was probably a good thing, since any service serving Tulse Hill station is likely to be restricted to 8 carriages for many years to come.

The main Thameslink route will be via London Bridge down the Brighton Main Line (BML). This will be almost a fully-segregated route down to at least just north of Norwood Junction on the fast lines, as the only other services using it will be the Uckfield services and a few empty coaching stock movements after the morning peak and prior to the evening peak.

London Bridge is only going to have 6 terminal platforms and – according to the RUS – 34tph in peak hours are going to enter London Bridge from the Brighton main line. Some of those services really are not suitable for inclusion into Thameslink (e.g. Caterham and Tattenham Corner services) so options are limited but it seems likely that Network Rail would like to get as many BML London Bridge terminators as they can onto Thameslink.

The RUS also states that “The RUS has not been able to robustly timetable any additional trains, with key contraints [sic] identified including the East Croydon area, and London Bridge platforms.” However note that that restriction does nothing to prevent running Thameslink services to Guildford via Norwood Junction, which was originally one of the favoured options and though subsequently discarded now seems up for consideration once again. This would at least mean that Sutton would retain a Thameslink service albeit at a reduced frequency.

We also have the East Grinstead line as a hot favourite for Thameslinks services, particulary as by then it will already be suitable for 12-car trains. A possible joker in the pack is the Uckfield line which is currently diesel operated but has seen tremendous growth now the service has improved and it is now recognised that many people from this area of Sussex just drive to the nearest convenient railhead with a decent service.

We can take for granted that existing Thameslink services on the BML will be retained and Horsham trains have always been a favourite for takeover by Thameslink. In recent years these have started moving away from Victoria and now often terminate at London Bridge. Sources suggest a further two semi-fast terminating services at Three Bridges (effectively a Horsham train not going all the way). So 12tph down the Brighton line as follows would not be an unreasonable guess:

4 x fast Brighton (as present) (12-car)
4 x semi-fast Three Bridges – two extended to Horsham (12-car)
2 x fast to East Croydon then all stations to East Grinstead (12-car)
2 x Norwood Junction, West Croydon then either seni-fast or all stations to Guildford. (8-car)

This leaves four 12-car trains and eight 8-car trains that need to take over a South East trains service. This could either be via Elephant and Castle or via London Bridge. The RUS gives no clue as to what they will be so we need to look back at the original proposals and the service currently run.

Possibilities are:

2 x fast Eastbourne via BML rerouted from serving Victoria (12-car)
2 x fast Littlehampton via BML and Hove rerouted from serving Victoria (12 car)
2 x all stations Sevenoaks via Elephant and Castle and Swanley (8 car)
4 x all stations Orpington via Elephant and Castle (8 car)
2 x fast Ashford International via London Bridge (8 or 12 car)
various options to take over South Eastern suburban services in particular some of the Dartford services.

The does, however, seem to be a horrible mismatch when it comes to the length of trains. South of the river most services will be at least 10-cars long and one doesn’t want to replace longer trains with shorter ones. It is almost inconceivable that South Eastern suburban services could manage with shorter trains without a corresponding increase in frequency that simply isn’t going to happen, so the Dartford option would only seem viable once Dartford station is rebuilt to take 12-car trains. Conversely, however, the Thameslink programme includes doubling Tanners Hill fly-down by St Johns station and there would be difficult to see any logic in including this construction work in the project if it were not to include an element of taking over some services running via Lewisham.

The fact is that the final decision is going to depend on other factors and it is not going to be made until it has to be (or as a cynic might say, if the DfT is involved, somewhat later than that). If Crossrail goes to Dartford then some of the pressure is taken off South Eastern services through London Bridge. Thameslink has a limited ability to take some pressure off Victoria services from the south by rerouteing some trains but this would probably not be popular with existing customers and would be done at the expense of relieving London Bridge.

Finally, possibly the most interesting thing about Thameslink in the RUS is not about Thameslink at all but the fact that it is going to have a major effect on a lot of lines. Like the project itself these final details are undecided, but Thameslink will lead to freeing up a few train paths, in particular into termini, and it is yet to be decided which services should benefit from this.

Another factor, often overlooked, is that because Thameslink runs a 15 minute interval timetable other timetables will have to be based on this. Let us presume that Thameslink take over a suburban service on South East trains. The suburban service would have to be entirely rewritten as it is all interdependent. Take as an example the Hayes line which, in the rush hour, currently has a 10 minute service with trains alternating between Charing Cross and Cannon Street. This 6tph service will not be possible, so either the service will have to go to 8tph (but there won’t be the spare paths so some other suburban service will lose out) or it goes down to 4tph and the overcrowding certainly won’t be popular with commuters on that line.

Whatever happens, the Thameslink programme will give plenty to write about as decisions about it are made and consequential changes gradually come to light.

Written by Pedantic of Purley