Could HS2 relieve the Welwyn bottleneck?

[Glenn1969]

I am hoping that HS2 will relieve the southern end of the ECML just as much as the WCML by rerouting London to Leeds, Newcastle and Scotland services to take advantage of high speed. Would that have the effect of relieving the Welwyn bottleneck?

 

[TrafficEng]

I am hoping that HS2 will relieve the southern end of the ECML just as much as the WCML by rerouting London to Leeds, Newcastle and Scotland services to take advantage of high speed. Would that have the effect of relieving the Welwyn bottleneck?

Funny you should mention HS2.

I have to apologise that I posted my previous comment without the concluding paragraph I intended to write. The effect of which was to say the post wasn't intended to stimulate further off-topic discussion, but instead was to make a general point about this scheme and others like it.

That is to say there seems to be an inconsistency in the approach adopted to rail investment with some schemes (like this one) apparently progressed on the basis of doing the absolute minimum necessary to resolve an immediate issue, and others clearly built to provide actual (or facilitate future provision of) additional capacity beyond that which is immediately necessary (or perhaps feasible).

 

[cle]

I would expect the same frequency of services, but the Leeds ones would all stop at the current intercity stations, plus maybe Huntingdon and Hitchin might be served again by services from further afield.

Stevenage today does better on calls than Watford or poor old Luton (hit by capacity but also the airport station), but I’d expect calls there to increase to all services. But the same services will run semi-fast to Leeds and York, and likely beyond.

I’d expect the Aberdeen and Inverness trains might lead to retaining an hourly fast pattern to Edinburgh at least. But now that might have Peterborough and Doncaster for all.

 

[adamedwards]

I would expect the same frequency of services, but the Leeds ones would all stop at the current intercity stations, plus maybe Huntingdon and Hitchin might be served again by services from further afield.

Stevenage today does better on calls than Watford or poor old Luton (hit by capacity but also the airport station), but I’d expect calls there to increase to all services. But the same services will run semi-fast to Leeds and York, and likely beyond.

I’d expect the Aberdeen and Inverness trains might lead to retaining an hourly fast pattern to Edinburgh at least. But now that might have Peterborough and Doncaster for all.

I remember Modern Railways a few years back speculating that there would be a Leeds to Stansted Airport service, rather than 2 per hour to London. I could imagine an hourly Lincoln to London overlapping with this. The end result will be a lot more commuter services and long distance stoppers, with fast trains from Euston first stop York.

 

[VT 390]

I would have thought that no services would be cut that currently exist as stations from Doncaster south will not have HS2 services to London so will need to keep their fast services, but I think all services will make more stops at places like Stevenage, Peterborough, Doncaster and possibly Newark and Grantham.

 

[TrafficEng]

In the context of this thread coming out of the Stevenage Platform 5 discussion and my earlier post, I think the thread title is asking the wrong question.

We ought to be asking "Should HS2 relieve the Welwyn bottleneck?". I believe there is more that could be done on the ECML to reduce the impact of the bottleneck and that ought to be progressed regardless of what happens with HS2.

As an example, the platform 5 scheme attempts to isolate the Hertford route from the main line to free up capacity on the down slow. However, that isolation is incomplete as anything coming from the Hertford direction and not terminating at platform 5 may need to wait on the single track section until it can join the down slow. Any passenger services behind will be unable to progress to Stevenage, and anything departing from platform 5 will be blocked. Of course if everything is running to timetable that shouldn't be a problem. But since disruptions do happen - and the Welwyn bottleneck is a facilitator of some of that disruption - it isn't unreasonable to think there is a fair chance of problems on the Welwyn route spilling over to the Hertford one (and vice versa).

A more comprehensive scheme (involving some doubling as per my original post) could have allowed trains going onto the down slow to wait where they wouldn't obstruct services to/from platform 5. That space could also be utilised to deal with a failing unit without blocking the only line/platform available for passenger services. It would also help remove the constraint on service frequency that the single line and platform represents.

Not being naive I appreciate a speculative idea like this requires a lot of money to make it happen, although arguably less than it will building it as an add-on in 10 years time.

Which to me is the fundamental issue here. How has the industry arrived in a position where it is accepted that the additional costs of building a 250mph railway are justified, but that additional costs on much smaller projects are not?

Is it because the answer to every capacity problem appears to be "HS2"?

 

[Ianno87]

In the context of this thread coming out of the Stevenage Platform 5 discussion and my earlier post, I think the thread title is asking the wrong question.

We ought to be asking "Should HS2 relieve the Welwyn bottleneck?". I believe there is more that could be done on the ECML to reduce the impact of the bottleneck and that ought to be progressed regardless of what happens with HS2.

As an example, the platform 5 scheme attempts to isolate the Hertford route from the main line to free up capacity on the down slow. However, that isolation is incomplete as anything coming from the Hertford direction and not terminating at platform 5 may need to wait on the single track section until it can join the down slow. Any passenger services behind will be unable to progress to Stevenage, and anything departing from platform 5 will be blocked. Of course if everything is running to timetable that shouldn't be a problem. But since disruptions do happen - and the Welwyn bottleneck is a facilitator of some of that disruption - it isn't unreasonable to think there is a fair chance of problems on the Welwyn route spilling over to the Hertford one (and vice versa).

A more comprehensive scheme (involving some doubling as per my original post) could have allowed trains going onto the down slow to wait where they wouldn't obstruct services to/from platform 5. That space could also be utilised to deal with a failing unit without blocking the only line/platform available for passenger services. It would also help remove the constraint on service frequency that the single line and platform represents.

Not being naive I appreciate a speculative idea like this requires a lot of money to make it happen, although arguably less than it will building it as an add-on in 10 years time.

Which to me is the fundamental issue here. How has the industry arrived in a position where it is accepted that the additional costs of building a 250mph railway are justified, but that additional costs on much smaller projects are not?

Is it because the answer to every capacity problem appears to be "HS2"?

I think you misunderstand why HS2's cost estimate has increased - it is generally not through adding extra bits and bobs onto the scheme (notably excluding such things as putting much of the London approaches in tunnel) - it's more down to the initial estimates (and thus budget), done many years ago, probably being frankly unrealistic - the revised forecast now better accounts for these things, as HS2 have developed the scheme and its design.

I'm sure HS2 must be equally under pressure to justify every bit of scope in its scheme. A notable example was it dropping provision of cycle path somewhere in the Burton Green area as part of the route. Lovely for HS2 to do of course, but adds cost and is nothing to do with providing an operational railway.

Meanwhile, your Stevenage example is a case of adding Bells & Whistles - all with cost of course with the extra track and signalling alterations needed - but offers very little operational benefit compared to just holding trains south of Bradbury(?) Jn towards Hertford to avoid the issue you describe. And there is nothing to stop it being added later if there is a genuine operational need.

 

[MarkyT]

Meanwhile, your Stevenage example is a case of adding Bells & Whistles - all with cost of course with the extra track and signalling alterations needed - but offers very little operational benefit compared to just holding trains south of Bradbury(?) Jn towards Hertford to avoid the issue you describe. And there is nothing to stop it being added later if there is a genuine operational need.

'Bragbury Jn' according to the Sectional Appendix, about two miles south of Langley Jn Down, where the Up GN trains would normally cross over to the UH. With a train stuck on the DH south of Bragbury Jn, Up and Down GN Stevenage terminators would both have to run on the UH for about 5 miles From Molewood Jn. Whether that would be a problem or not depends on where they would normally pass each other. Both lines are fully bi-directionally signalled, so an alternative might be to cross the train that has to wait to get out at Langley Jn Down over at Molewood Jn to the UH and wait just south of Langley South Jn instead, running the Stevenage terminators over the DH in both directions as far as Bragbury Jn. How useful either of these strategies would be would depend largely on how early the regulating problem became apparent. Practically, there will probably be few trains on the Hertford Loop that go north of Stevenage in normal running conditions. During planned engineering diversions via the Loop, a reduced overall service would be likely so ensuring a through platform at Stevenage can be made available quickly at all times at Stevenage would be the best bet, and any small incoming delay incurred by a terminator might be absorbed in the turnback layover.

 

[TrafficEng]

I think you misunderstand why HS2's cost estimate has increased - it is generally not through adding extra bits and bobs onto the scheme (notably excluding such things as putting much of the London approaches in tunnel) - it's more down to the initial estimates (and thus budget), done many years ago, probably being frankly unrealistic - the revised forecast now better accounts for these things, as HS2 have developed the scheme and its design.

No, I understand why the costs of HS2 have increased, and to an extent agree with you that the original estimates were unrealistic.

My point was why are we in the position of accepting (although not universally) that the additional costs of building the line to be able to operate at 250mph rather than some lower speed, a decision I understand to have been made at a very early stage of the process and I accept now quite difficult to reverse.

I can understand the logic of building infrastructure which is future-proofed, but does anybody expect UK trains to ever operate at that speed (in a realistic timeframe), and if they do, will the future benefits be as great as benefits that might be achieved today as a result of different spending decisions?

It is the inconsistency in approach I find puzzling. Either we accept the need to invest in "bells and whistles" to future proof what we do, or we cut our cloth the the budget available.

Meanwhile, your Stevenage example is a case of adding Bells & Whistles - all with cost of course with the extra track and signalling alterations needed - but offers very little operational benefit compared to just holding trains south of Bradbury(?) Jn towards Hertford to avoid the issue you describe. And there is nothing to stop it being added later if there is a genuine operational need.

I'm not sure where the location you mention is, but from what I can see there is nothing north of Watton which would allow a northbound passenger service to pass something else ahead of it waiting to join the down slow. Sure, passengers could wait until the line ahead clears and they can finally get into platform 5, but then that train is occupying the single line until it departs platform 5 (by now possibly late) and eventually gets to Langley South junction. That in turn has the potential to delay the next northbound service, and so on.

My original point in the Platform 5 thread wasn't so much about the need to build it now, but whether the current works would allow whatever might be needed to be constructed without altering what has just been constructed, and without excessively increasing future costs. If there is nothing to stop it being added later then all well and good.

By the way, my comments aren't intended as a criticism of the people involved in the project. I was just trying to explore the apparent difference in approach between HS2 (and TfL funded projects) where money is spent for the future, whereas on some national rail projects the approach feels more like 1980's "do the absolute minimum we have to".