Possible Solutions to increase capacity between Bedford and St Pancras?

[Ianno87]

you're wrong... north of KT there are 2 lines available in each direction... fast and slow... just because trains to St P don't use the slow lines doesn't mean that they aren't able to!

The Slow Lines are full (quite literally) of Slow stopping trains, plus trains exiting the Thameslink core and crossing across the Slows to the Fast lines. No space for any more Slow Line moves out of St P high level (save the odd EMT ECS move)

Trains from St P high level are fast to at least Luton Airport Parkway. Put them on the Slows and you smash at least 10 minutes on their journey times straight away, through being pathed out in between stoppers.

So trains out of high level are de-facto restricted to one line north of Carlton Rd in practice.

 

[Dr Hoo]

Really showing my age now, but as a very junior clerk I worked on the Midland Suburban Electrification project in the 1970s. Well remember the old semaphore signalling on the route once you got past the ‘modern’ OCS power box at St Pancras from the 1950s.
Back in the old days one pair of tracks from St Pancras to Finchley Road (i.e. well past Kentish Town and through Belsize Tunnel) was effectively ‘goods’ and the other ‘passenger’. Yes, there were connections immediately outside St P that enabled you to put a passenger train into the goods lines during engineering works or failures but the goods lines were really to serve Somers Town and St Pancras Goods depots. The goods lines did not go through platforms at Kentish Town.
All main line and suburban trains merged at a conventional double junction at Finchley Road. There was a double junction at Carlton Road that gave access to the Moorgate lines (as well as the Barking Line). The platforms at Kentish Town meant that stopping trains to/from St P got in the way of long distance expresses. Hardly anything went to Moorgate in those days, of course.
The new West Hampstead scheme (a brilliant project for its era) created a three-track passenger layout into St Pancras alongside a pair of ‘slow’ tracks towards Moorgate.

 

[Bald Rick]

hmm... well the 4 lines originally went all the way to St Pancras, so if the slow lines now merge into the fast lines south of Kentish Town then that is just another failing of HS1/ Thameslink programmes in that instead of alleviating bottlenecks they have increased the number by 1! As to your assertion that the conflict is only on one line.... well it's still a conflict isn't it? ok so the current is 4tph/ off peak 8 tph peak... but it is envisaged once the Thameslink programme is completed there will be at least 6 tph fast off peak, with, I presume, a corresponding increase in the peak service.. however, even going with 8tph that is, on average, a conflict every 7.5 minutes.... how long must the conflicted line be blockaded before and after the Thameslink train has manouvred a minute before and 30 secs after passing? so for every 7.5 mins the route south into St Pancras is unavailable for 1.5 mins or to put it another way the up fast is unavailable for use for 20% of the time.. that must impact on the number of trains EMT can run into St Pancras!

Just to point out some facts.

There haven’t been 4 lines into St Pancras HL from the MML since West Hampstead resignalling 40 years ago. Nothing to do with Thameslink or HS1. Pre HS1 it was a tortuous approach, with (IIRC) a 10mph approach. It is far better now.

The 4tph off peak / 8tph peak fast line service is the final pattern for Thameslink. It doesn’t go to 6tph off peak, nor any further peak increase.

 

[Teflon Lettuce]

Just to point out some facts.

There haven’t been 4 lines into St Pancras HL from the MML since West Hampstead resignalling 40 years ago. Nothing to do with Thameslink or HS1. Pre HS1 it was a tortuous approach, with (IIRC) a 10mph approach. It is far better now.

How odd then that in all my journeys as a child that I could count 4 lines at West Hampstead... and also onto Kentish Town and St Pancras... before the rebuilding there were 7 platforms at St Pancras which funnelled onto 4 running lines... not 2

The 4tph off peak / 8tph peak fast line service is the final pattern for Thameslink. It doesn’t go to 6tph off peak, nor any further peak increase.

Is it? do you want to tell Thameslink.... they are quite adamant in their publicity for the project that the eventual pattern will be 6tph fast to Bedford!

From official sources:

https://www.railplan2020.com/improvements/thameslink-railplan2020


Improvements to Thameslink include:
From May 2018

• Littlehampton and Horsham to London Bridge services transfer to Thameslink, with a new timetable and travel opportunities
• Anyone travelling from London Bridge to East Croydon (and onward interchange) will see a significant uplift in services
• Thameslink services diverted via Crystal Palace start to call again at London Bridge
• New Thameslink services between Luton and Rainham
• Catford Loop – doubling off-peak services to London, bringing extra capacity on this route
• A significant increase in frequency of trains between St Albans and St Pancras
• Some Great Northern services to Cambridge will transfer to Thameslink, simplifying journey options and providing access to new destinations
• Additional services from Littlehampton to London Bridge, through London and up to Bedford
• Additional Great Northern services to Cambridge will transfer to Thameslink
• The interconnection with the Elizabeth Line (Crossrail) presents new simplified journey options and destinations

{my bold}

so new service to Luton, significant increase of services to St Albans and a new service to Bedford... so unless you are telling me that every single new train will be all stns then there will be extra Thameslink trains on the fast lines...

 

[Verulamius]

The Thameslink plans are off-peak: 4 fast line and 6 slow line - peak : 8 fast line and 8 peak.

The Luton Rainham services are on the slow lines.

The December 2018 is the final Thameslink timetable on the MML side I believe.

 

[Teflon Lettuce]

The Thameslink plans are off-peak: 4 fast line and 6 slow line - peak : 8 fast line and 8 peak.

The Luton Rainham services are on the slow lines.

The December 2018 is the final Thameslink timetable on the MML side I believe.

4 fast and 6 slow? that doesn't add up... the legacy services are already 4 fast and 4 slow... adding in the extra Luton service is another 2tph and then adding the new Bedford- Littlehampton service adds another 2tph.... and then there is the "significant increase" in services to/ from St Albans.

All this is semantics though... as I pointed out in an earlier post even at 4tph on the fast lines that means 8 tph conflicting the fast line southwards... meaning it is unavailable for pathing of MML trains into St Pancras for 20% of the available time {based on a 90 second blockade for each crossover}

 

[ijmad]

Sparkyscrum's excellent diagram shows the final Thameslink timetable and the stopping patterns, it's pretty easy to guess which are on the fast lines and which on the slow by looking at the stopping patterns:

https://www.flickr.com/photos/mackenzieblu/28145412708/sizes/k/

This video from Thameslink gives the original intended date of each route being introduced, but this is now inaccurate as anything earmarked for December 2018 is not happening. They are instead giving (most of) the original May 2018 timetable another go.

There will eventually be 24 peak time paths per hour through the Thameslink core, 16 of which are allocated to the Midland Main Line, 8 of which are allocated to East Coast Main Line. Of the 16, 8 will go as far as Bedford with various stopping patterns, with 4 more terminating at Luton, and 4 more at St Albans (8+8).

Outside of the peak this will be 4tph as far as Bedford, with a further 2tph going as far as Luton, and 4tph still to St Albans (4+6).

Beyond December's second attempt at May, in terms of Bedford/Luton/St Albans services, the main one still to be introduced is an extra train from Bedford to Littlehampton during the peaks. I guess that might happen next year. That's it.

 

[Dr Hoo]

How odd then that in all my journeys as a child that I could count 4 lines at West Hampstead... and also onto Kentish Town and St Pancras... before the rebuilding there were 7 platforms at St Pancras which funnelled onto 4 running lines... not 2..

As I tried to explain in Post #62 there were never four passenger lines into St Pancras.

West Hampstead had four passenger lines and platforms (with two goods lines on the ‘south’ side that ran all the way to Silkstream Junction, north of Hendon).

The passenger lines merged into a single pair at Finchley Road and ran through the north bore of Belsize Tunnel while the goods lines ran through the south bore.

At Carlton Road Junction the passenger lines split back into four but with one pair effectively only going to Moorgate. (Yes, I know that there were some more crossovers at Kentish Town but these were only generally used to cross trains from the Barking Line into St Pancras, such as Tilbury boat trains.)

The two pairs of passenger lines continued through the four platforms at Kentish Town and the goods lines continued on the west side of the formation. At Dock Junction the Moorgate lines finally split off and the two remaining passenger lines continued into St Pancras.

The goods lines went into Somers Town and gave access to St Pancras Goods. There were limited low speed connections that would allow moves from the station itself to the goods lines but these were more for things like locomotive moves across the layout than through movements.

As I tried to explain before, it was something of an ‘event’ for a passenger train to be sent via the goods lines, which had to be cleared specially.

 

[Teflon Lettuce]

As I tried to explain in Post #62 there were never four passenger lines into St Pancras.

West Hampstead had four passenger lines and platforms (with two goods lines on the ‘south’ side that ran all the way to Silkstream Junction, north of Hendon).

The passenger lines merged into a single pair at Finchley Road and ran through the north bore of Belsize Tunnel while the goods lines ran through the south bore.

At Carlton Road Junction the passenger lines split back into four but with one pair effectively only going to Moorgate. (Yes, I know that there were some more crossovers at Kentish Town but these were only generally used to cross trains from the Barking Line into St Pancras, such as Tilbury boat trains.)

The two pairs of passenger lines continued through the four platforms at Kentish Town and the goods lines continued on the west side of the formation. At Dock Junction the Moorgate lines finally split off and the two remaining passenger lines continued into St Pancras.

The goods lines went into Somers Town and gave access to St Pancras Goods. There were limited low speed connections that would allow moves from the station itself to the goods lines but these were more for things like locomotive moves across the layout than through movements.

As I tried to explain before, it was something of an ‘event’ for a passenger train to be sent via the goods lines, which had to be cleared specially.

yes I did understand all that... but you said that was up to the 60's... the period I'm talking about is the mid 70's onwards.. don't ask me why but as a kid I had a fascination of following the tracks as we went along... and most definitely there were 4 continuous tracks from West Hampstead through to St Pancras... whether the "slow" lines were ever routinely used for passenger trains between the 2 points I couldn't say.. but the layout allowed the possibility...

 

[edwin_m]

yes I did understand all that... but you said that was up to the 60's... the period I'm talking about is the mid 70's onwards.. don't ask me why but as a kid I had a fascination of following the tracks as we went along... and most definitely there were 4 continuous tracks from West Hampstead through to St Pancras... whether the "slow" lines were ever routinely used for passenger trains between the 2 points I couldn't say.. but the layout allowed the possibility...

It's very unlikely that the layout would have changed significantly from the 60s up until re-signalling in the run-up to electrification. I think your point is consistent with earlier posts by Dr Hoo that there were four tracks but the southern pair (now the Fast lines) wouldn't normally have carried passengers.

 

[Bald Rick]

Is it? do you want to tell Thameslink.... they are quite adamant in their publicity for the project that the eventual pattern will be 6tph fast to Bedford

It doesn’t say that anywhere.

4 fast and 6 slow? that doesn't add up... the legacy services are already 4 fast and 4 slow... adding in the extra Luton service is another 2tph and then adding the new Bedford- Littlehampton service adds another 2tph.... and then there is the "significant increase" in services to/ from St Albans.

All this is semantics though... as I pointed out in an earlier post even at 4tph on the fast lines that means 8 tph conflicting the fast line southwards... meaning it is unavailable for pathing of MML trains into St Pancras for 20% of the available time {based on a 90 second blockade for each crossover}

The Littlehamptons are simply fast services that used to go to destinations on the southeastern (Orpington, Beckenham Jn, etc.) but redirected. They are not extra trains on the MML.

Re the ‘20% of the available time’ that the Up Fast is blocked by a crossing move. Guess what happens to trains on the Up Fast during that time? They are Thameslink trains crossing at West Hampstead South Jn, as a parallel move, to head to the core.

 

[Bald Rick]

It's very unlikely that the layout would have changed significantly from the 60s up until re-signalling in the run-up to electrification. I think your point is consistent with earlier posts by Dr Hoo that there were four tracks but the southern pair (now the Fast lines) wouldn't normally have carried passengers.

And it also didn’t change significantly from resignalling in the late 70s until HS1 came along.

 

[Teflon Lettuce]

ok... well getting back to the point of the thread... how much extra capacity would

The Littlehamptons are simply fast services that used to go to destinations on the southeastern (Orpington, Beckenham Jn, etc.) but redirected. They are not extra trains on the MML.

Oh? the Littlehamptons aren't extra trains on the MML? so there will be 2 tph Bedford-London-Gatwick and 2 tph Bedford- London- Brighton and then there will be 2 tph Littlehampton- London- Bedford. Now.. either there are 2 stns called Bedford on the Thameslink network or Bedford has moved off of the MML or there will be 2 more tph fast on the MML part of the thameslink network... which is it?

I suggest you spend less time nitpicking the minutiae of what someone says and instead argue the broad point that they make. The title of this thread is "how to increase capacity Bedford- St Pancras" I pointed out that a major bottleneck has to be where thameslink and MML merge just south of Kentish Town due to the conflicting movements that need to be made... now... does the layout in fact cause the problem I identified? yes which then leads to the questions "what can be done to ease/ eliminate this bottleneck? and "how much extra capacity would a given solution deliver?"

 

[EM2]

But has been pointed out, the movements are not conflicting, they are parallel.

 

[Bald Rick]

ok... well getting back to the point of the thread... how much extra capacity would


Oh? the Littlehamptons aren't extra trains on the MML? so there will be 2 tph Bedford-London-Gatwick and 2 tph Bedford- London- Brighton and then there will be 2 tph Littlehampton- London- Bedford. Now.. either there are 2 stns called Bedford on the Thameslink network or Bedford has moved off of the MML or there will be 2 more tph fast on the MML part of the thameslink network... which is it?

I suggest you spend less time nitpicking the minutiae of what someone says and instead argue the broad point that they make. The title of this thread is "how to increase capacity Bedford- St Pancras" I pointed out that a major bottleneck has to be where thameslink and MML merge just south of Kentish Town due to the conflicting movements that need to be made... now... does the layout in fact cause the problem I identified? yes which then leads to the questions "what can be done to ease/ eliminate this bottleneck? and "how much extra capacity would a given solution deliver?"

It might be picky, but it’s important that the facts are set out, as there are plenty of people who read this forum who might believe erroneous information.

The Bedford - Littlehamptons are peak only, as are the Bedford - East Grinsteads. 2tph of each add to the Bedford - Brightons and Bedford - Gatwicks (also 2tph each, but all day) to get to 8tph peak.

The biggest constraints on capacity on the MML Fast lines is simply that there are 13/14 tph in the peak between Carlton Rd / West Hampstead and Radlett / Harpenden, and these trains have a variety of stopping patterns from St Albans (inclusive) northwards. You could get a couple more in, on the existing infrastructure, but the average speeds would have to be equalised, ie either slow down the EMTs or drop calls off the Thameslinks. And turn round time would have to be shortened at St P (high level).

 

[edwin_m]

But has been pointed out, the movements are not conflicting, they are parallel.

However they are only non-conflicting if both arrive on time (or equally late I suppose). As soon as one is late it starts creating conflict, and delays other trains that are also scheduled to make parallel moves at flat junctions. This is the one reason why Thameslink is prone to falling into chaos when there are a few random delays.

 

[EM2]

However they are only non-conflicting if both arrive on time (or equally late I suppose).

But you can't plan timetables assuming that trains will be late. That way madness lies.

 

[Meerkat]

But you can build grade separation, which is why I asked whether it was practicable a while back.

 

[Teflon Lettuce]

But you can't plan timetables assuming that trains will be late. That way madness lies.

no more mad than running a line at 100% capacity on the assumption that a train will NEVER be late...

 

[Ianno87]

But you can build grade separation, which is why I asked whether it was practicable a while back.

The whole area is in deep cutting with numerous overbridges, so unlikely to be grade seperable for any sensible cost or level of disruption.

Best space for grade separation probably somewhere north of West Hampstead, but then you lose capacity because the Thameslink fasts have to bumble along behind the stoppers for longer.

 

[Teflon Lettuce]

The whole area is in deep cutting with numerous overbridges, so unlikely to be grade seperable for any sensible cost or level of disruption.

Best space for grade separation probably somewhere north of West Hampstead, but then you lose capacity because the Thameslink fasts have to bumble along behind the stoppers for longer.

but would the cost of realigning the TL/MML junction at KT so that the lines run direction seperated KT- Cricklewood with a flyover at Cricklewood to put the lines back into the traditional MML configuration {UDUD} have really been that great in the grand scheme of how much the whole Thameslink project cost?

 

[Dr Hoo]

but would the cost of realigning the TL/MML junction at KT so that the lines run direction seperated KT- Cricklewood with a flyover at Cricklewood to put the lines back into the traditional MML configuration {UDUD} have really been that great in the grand scheme of how much the whole Thameslink project cost?

Sorry, you have really lost me. You seem to be suggesting an isolated segment of 'paired by direction' lines in the middle of the busiest part of an otherwise wholly 'paired by use' route.
What is this intended to achieve, let alone what it would cost in terms of grade separation?

 

[Teflon Lettuce]

Sorry, you have really lost me. You seem to be suggesting an isolated segment of 'paired by direction' lines in the middle of the busiest part of an otherwise wholly 'paired by use' route.
What is this intended to achieve, let alone what it would cost in terms of grade separation?

It would stop all conflicts of TL trains moving onto the fast MML lines. My suggestion would involve realigning the NB Thameslink tunnel and creating a flyover at Cricklewood... I just wondered how cost effective a solution it would've been in the grand scheme of the Thameslink project. As I see it by removing the conflicts would increase capacity into St Pancras terminal by approx 20%

 

[edwin_m]

As per #81 I agree you'd have to go out beyond West Hampstead before a flyover becomes possible. It might be possible (but not cheap) to put a junction in the northbound tunnel so trains destined for the Down Fast could use a separate tunnel and surface next to that line. The other direction would be more difficult but the flat crossing in that direction only conflicts with the Down Slow so may be less of a problem.

Having done any of these things you are back to the DUDU configuration so a flyover at Cricklewood isn't necessary. But one somewhere around St Albans or Harpenden would be useful to cross the Thameslinks from the Down Fast back onto the Down Slow roughly where they become stoppers. I seem to recall proposing one in a cutting on the rural section between those two stations.

 

[Dr Hoo]

It would stop all conflicts of TL trains moving onto the fast MML lines. My suggestion would involve realigning the NB Thameslink tunnel and creating a flyover at Cricklewood... I just wondered how cost effective a solution it would've been in the grand scheme of the Thameslink project. As I see it by removing the conflicts would increase capacity into St Pancras terminal by approx 20%

Right, one step at a time.
There is no 'northbound Thameslink tunnel' on the 'Midland side'. Thameslink essentially runs in double track tunnels with a line in each direction. Where, exactly do you mean? Please feel free to quote actual locations such as Dock Junction, Carlton Road Junction, Belsize Slow Tunnel, etc.

 

[EM2]

no more mad than running a line at 100% capacity on the assumption that a train will NEVER be late...

Before the rebuild, London Bridge was at 105% in the morning peak.

 

[Teflon Lettuce]

Right, one step at a time.
There is no 'northbound Thameslink tunnel' on the 'Midland side'. Thameslink essentially runs in double track tunnels with a line in each direction. Where, exactly do you mean? Please feel free to quote actual locations such as Dock Junction, Carlton Road Junction, Belsize Slow Tunnel, etc.

I don't know the exact names of the locations.. I'm no expert and have never claimed to be... I am relying a lot on my memory of many years of using the line aided by google maps... so here goes... as you come out of the Thameslink tunnels both TL lines run parallel to the 4 MML lines from St Pancras... so my idea is that before rising be level with the MML the NB thameslink go through a tunnel under the MML to give a paired by direction configuration.... to be rectified back to paired by use by a flyover either north or south of Cricklewood.... it would have to be here as it is the first place where there's room... also north of Cricklewood the slow lines wander about a bit

 

[Verulamius]

What about this for a reorganisation of directions on the MML. Lots of issues with this though, including access to the Cricklewood sidings.

Out of St Pancras High level the two main track directions are reversed so that the up is on the west side.

This way just before the tunnels the two down tracks (one each from High Level and low level) are next to each with possible easy crossing.

From the tunnels up to Hendon there are 5 main tracks (plus one for freight) UF, DF, DS, US, Up Thameslink Fast. There is an extra Up line used for fast Thameslink services. The slow lines are in the centre of the platforms. The UF is using one of the Freight lines without platforms.

The freight flyover is converted to passenger use and the UF joines the UTF. So by Mill Hill you have DDUU (looking north) with the fasts on the outside.

You would need to change the sidings arrangement at St Albans for the centre platforms, and the Radlett freight terminals are problematic.

You would then need to change back to the historic layout after St Albans with a new flyover.

 

[Teflon Lettuce]

What about this for a reorganisation of directions on the MML. Lots of issues with this though, including access to the Cricklewood sidings.

Out of St Pancras High level the two main track directions are reversed so that the up is on the west side.

This way just before the tunnels the two down tracks (one each from High Level and low level) are next to each with possible easy crossing.

From the tunnels up to Hendon there are 5 main tracks (plus one for freight) UF, DF, DS, US, Up Thameslink Fast. There is an extra Up line used for fast Thameslink services. The slow lines are in the centre of the platforms. The UF is using one of the Freight lines without platforms.

The freight flyover is converted to passenger use and the UF joines the UTF. So by Mill Hill you have DDUU (looking north) with the fasts on the outside.

You would need to change the sidings arrangement at St Albans for the centre platforms, and the Radlett freight terminals are problematic.

You would then need to change back to the historic layout after St Albans with a new flyover.

As I said above, you'd have to "correct" the layout by Cricklewood as having a fast line on what is currently a slow alignment between Cricklewood and Mill Hill would involve serious upgrades... the slow lines between these points really do meander.

 

[Dr Hoo]

I don't know the exact names of the locations.. I'm no expert and have never claimed to be... I am relying a lot on my memory of many years of using the line aided by google maps... so here goes... as you come out of the Thameslink tunnels both TL lines run parallel to the 4 MML lines from St Pancras... so my idea is that before rising be level with the MML the NB thameslink go through a tunnel under the MML to give a paired by direction configuration.... to be rectified back to paired by use by a flyover either north or south of Cricklewood.... it would have to be here as it is the first place where there's room... also north of Cricklewood the slow lines wander about a bit

Right, I get you.
Sadly I think that the idea of a northbound fast Thameslink diveunder is a non-starter in engineering terms. While we were looking at slab track for the new fast lines on the old goods lines through Kentish Town the retaining wall started to give way. It has been dramatically rock anchored. There is no way, short of massive land purchase and demolition, probably with a major blockade at least of St Pancras high level, that you could create an exit for the diveunder.