Postscript: Thameslink and The Transport Committee

We really were going to take a break from Thameslink and look at a few completely different topics. We recently covered Thameslink twice – here and here. Then along came the GLA Transport Committee and their questioning of almost certainly the most appropriate person to ask about what is going on with Thameslink. The relevant answers given by Paul Harwood, Chief Network Planner at Network Rail, may only occupy three minutes (1:47 to 1:50) of the Transport Committee’s deliberations but for the first time they provide what are fairly definitive answers from an official source at Network Rail.

Confusion at Network Rail

Paul was initially asked by Val Shawcross to give an update on the recent DfT statement and its consequences. In reply he stated that:

I have been talking to the Department of Transport about this because we are pushing them to clarify the continuation of that statement because it says about one part of the service change and not the rest.

So clearly there is more that needs to be decided by the DfT. And also clearly it is now ultimately the DfT who calls the shots as to services provided which we must remember was not the case when the case when Thameslink was approved.

Explaining the consequences of the decision

Paul was asked to explain how the decision would affect other services and here we get to the crux of the matter. It must be remembered the announcement was not only about trains on the Wimbledon Loop. In passing it mentioned that there would only be 16tph via London Bridge.

The decision about the Wimbledon Loop we think only works if you have additional infrastructure provided. So our original statement was around the infrastructure as specified for Thameslink. We have worked with the Department for Transport on another infrastructure solution in the Cannon Street area which is critical. Linking to that, the change in specification would mean additional services that were going to run through the core will now run into Cannon Street. That is effectively a summary of the change. Some of these services are ones that the department in their consultation proposed to be through the core of Thameslink and heading further north but there was some response as well to that consultation say that people wanted to retain the Cannon Street services.

This reply is a bit confusing because it appears to be talking more about the announcement about having only 16tph on Thameslink through London Bridge and not really about the Wimbledon Loop. As far as capacity from Kent to the approaches to London Bridge are concerned it doesn’t really matter if a train is a Thameslink one or a Cannon Street one. So the issue being talked about must be the ability to get 24tph in and out of Cannon Street to and from London Bridge. East of London Bridge we must presume that there is no problem. This issue would appear to be the so-called “Cannon Street empties” problem.

The Cannon Street Empties Problem

Cannon Street is very much a station in the peak where the flow against the main rush hour direction is absolutely minimal. For this reason many trains leave in the morning peak out of service. Because of the layout at Borough Market Junction before 1976 it was very difficult to path an “empty” without all sorts of conflicting moves. To get around this some empties were routed out of the station via Metropolitan Junction to Blackfriars from where they could continue to a carriage siding without affecting the busy inward train service to London Bridge. After 1976 the rationale for them had somewhat diminished but it was established practice and it did have its advantages. In particular it is likely that capacity through the three tracks at London Bridge for trains to and from Cannon Street is close to the theoretical limit. More trains can go to and from Charing Cross because there are four through tracks – even if there are only three platforms.

It would appear that originally post-Thameslink the intention was to have a maximum of 22tph in and out of Cannon Street. The sending of Cannon Street empties via Blackfriars would not be possible because the trains would need to enter an ATO signalling area and so be appropriately equipped. This meant the Metropolitan junction would serve very little useful purpose and originally it was intended to remove it but later it appears that that is now in some doubt.

It now appears that Cannon Street will receive 24tph and that the current infrastructure cannot handle that. It would seem that Network Rail have a solution but it requires the co-operation (and presumably money) from the Department of Transport. We do not know what that solution would be but possibilities are:

• Reinstate 4-tracking between on the approach to Cannon Street. This was reduced to 3 reversible tracks in the late eighties to allow for the greater loading gauge of the new Networker trains. It is possible that reinstatement of this may allow an empty to depart from Cannon Street to free a platform and stand on a running line until a slot was available to proceed through London Bridge. Of course this would probably mean that the viaduct would have to be widened by a small amount.
• Reinstate the two sidings to the west of Cannon Street and possibly use the very tight Metropolitan curve (which for many years was double track) as a siding or two.
• Somehow get over the ATO problem and send them via Blackfriars as before. The problem now is that the train would have to reverse on one of the down running lines but this may well be possible. See page 22 of this document for the proposed layout for the Blackfriars approaches from 2018 onward.

Of course Network Rail’s actual solution may be none of these options.

The picture becomes a little clearer

The department are putting together two sets of consultation responses but it is predominately services from Dartford and Orpington which were originally scheduled or proposed to go through the core will be terminating at Cannon Street and I think to a certain extent terminating in the Blackfriars bays and therefore not be running through either which is the swap with the Wimbledon services.

Although not totally clear this tells us an awful lot. We now know that the plan until recently was to have 2tph from Dartford via London Bridge to join Thameslink and it is this service which will now (continue to) run to Cannon Street. We also know that a proposed service was from Orpington but that this will now run via Elephant & Castle or at least we presume this is true. So it would appear that the bay platforms at Blackfriars will be used to 2tph from Orpington with the remaining 6tph likely to be coming from a combination (0 or more) of Kent House, Beckenham Junction, Bellingham and Rochester.

A plan to increase frequency on the Wimbledon Loop is dashed

The other consequence is the Wimbledon services won’t see the uplift in service frequency that we proposed. We are fairly certain that that doesn’t work because effectively the bay platforms are effectively full up with this integrated specification.

To be clear, it is the decision to route the Orpington trains via Elephant & Castle and not London Bridge which effectively fills up the bay platforms and is nothing to do with the Wimbledon Loop decision. One could try and be clever and manage more than 4tph in each platform but with 2tph to various destinations evenly temporally spaced out it makes it much more sensible to stick to a safe 4tph in the platforms.

From the above it would seem that Network Rail has proposed increasing the service on the Wimbledon Loop. One presumes that this was privately to the DfT as there appear to be no public references specifically to the loop, although the London and South East RUS did mention additional services would be possible when the Brighton services all went via London Bridge. It would also seem that soon after 2018 train services are going to be restricted because there are insufficient terminating platforms at Blackfriars. This may be only temporary if the service through the core eventually increases beyond 24tph at some point in the future.

So it seems that as a result of consultation and the DfT listening to the responses and concerns about people losing their direct services, more trains will go to Cannon Street than originally planned. Also as consequence of this 2tph which were going to go via London Bridge will now go via Elephant & Castle. Because of this there are no spare slots into the bay platforms. And because of this a plan to improve the frequency of service on the Wimbledon Loop, which is what the passengers probably really want more than direct trains, cannot now take place. Oh the irony!

Performance Impact

Paul Harwood continues:

The other concern is that we are left with is the performance implications of this decision. So, fine, we have worked through with the Department for Transport. It is the usual difference, there is a theoretical timetable there we continue to develop with them. That works and enables them to make that announcement but we are concerned about the performance implications … that around the use of the infrastructure that is being put in place.

It would appear then that we now have bit more clarity on some of the issues where there were some unknowns but now some more unknowns and questions have appeared. One gets the feeling that there will be further articles on Thameslink in the not too distant future.