Reinstating passing loops on the Chiltern Sudbury stations

[Harpo]

I don’t know the signalling headways there but (simplistically) if it were three minutes you’ve got a minimum of six minutes dwell for the service being overtaken and a reliance on both trains running perfectly.

 

[Mgameing123]

It's now pretty impossible to put platforms on the met line or CML at West Hampstead due to all of the housing development that has sprung up on ex railway land around West Hampstead.
Although in the late 2000's Chiltern had a plan to use that railway land to build plats for the met line and CML at West Hampstead but in the end that fell through due to the financial crash of 2008.
Quite a shame it never got built to be honest.

We knock down the housing developments as we could get alot more housing developments if we get this done.

== Doublepost prevention - post automatically merged: 1 Jun 2025 ==

It's now pretty impossible to put platforms on the met line or CML at West Hampstead due to all of the housing development that has sprung up on ex railway land around West Hampstead.
Although in the late 2000's Chiltern had a plan to use that railway land to build plats for the met line and CML at West Hampstead but in the end that fell through due to the financial crash of 2008.
Quite a shame it never got built to be honest.

I'd say that the Met Line is possible with the space we have now if we convert the giant Jubilee Line island platform into 2 smaller island platforms similar to the ones at Finchley Road.

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At this point, wouldn't electrifying the Chiltern mainline, reinstating through loops at Beaconsfield, and a total reconfigure of High Wycombe be a more useful outcome?

High Wycombe could do with some additional platforms.

 

[HSTEd]

I don't think there's sufficient passive provision at OOC for that. Though what infrastructure would be needed to send the Chiltern services into Paddington now crossrail has taken most of the locals?

Probably a substantial length of new tunnel, and possibly a new underground pair of platforms at Old Oak Common.

How many trains actually leave Marylebone for the Chiltern Main Line each hour?

 

[MatthewHutton]

I think the most sensible thing to do if you are going to do anything is to four track from Gerrards Cross station to the high Wycombe tunnel beyond Beaconsfield. That gives you a long bit for overtaking and would allow you to run a proper half hourly service to Oxford, Birmingham and therefore have a half hourly stopper to High Wycombe.

I think you could also do a quarter hourly stopper as far as Ruislip.

I don’t think there is much in the way and you would also hopefully be able to open a station in East Wycombe.

== Doublepost prevention - post automatically merged: 1 Jun 2025 ==

Probably a substantial length of new tunnel, and possibly a new underground pair of platforms at Old Oak Common.

How many trains actually leave Marylebone for the Chiltern Main Line each hour?

2 Oxford, 2 Birmingham, 1 Wycombe, more at peak.

== Doublepost prevention - post automatically merged: 1 Jun 2025 ==

I'd say that the Met Line is possible with the space we have now if we convert the giant Jubilee Line island platform into 2 smaller island platforms similar to the ones at Finchley Road.

There is a challenge with Jubilee line access at West Hampstead. It’s just about acceptable as it stands as it is grandfathered in.

if you were to stop the Chiltern line or the Met line you would need to spend a lot of money on the access.

 

[The Planner]

I don’t know the signalling headways there but (simplistically) if it were three minutes you’ve got a minimum of six minutes dwell for the service being overtaken and a reliance on both trains running perfectly.

It is 3 minutes and you would be looking at a 5 minute dwell at a station.

== Doublepost prevention - post automatically merged: 1 Jun 2025 ==

I think you could also do a quarter hourly stopper as far as Ruislip.

No chance. It takes 18 minutes to get to Northolt Park Jn, so the next train can't pass until xx.21, so if thats a fast it can't leave Marylebone until xx.11. If the next stopper leaves at xx.15 you can only run 4 fasts per hour.

 

[MatthewHutton]

If the next stopper leaves at xx.15 you can only run 4 fasts per hour.

Well they only run 4 fasts an hour!

Would need tweaking for the peak to be fair.

 

[Zomboid]

This might be where (effectively) closing one of the Sudburys and serving the other at 15 minute intervals might buy enough to make it work.

That gap between xx00 and xx11 can be filled with an Aylesbury service.

 

[cle]

Small matter of the M25, and, err, HS2 in the way!

Indeed. But was giving an example of the type of length needed to make it worthwhile. More local stations on this side vs the Beaconsfield side (with outer calls too)

 

[sad1e]

This might be where (effectively) closing one of the Sudburys and serving the other at 15 minute intervals might buy enough to make it work.

That gap between xx00 and xx11 can be filled with an Aylesbury service.

I think that Sudbury Hill Harrow would be the best contender to keep. It has much nicer shelters , much wider platforms and is closer to the Piccadilly line then Sudbury and harrow road.
Sudbury hill harrow would also be easier to put loops on as it retains it's original platforms , although somewhat overgrown.

Sudbury and harrow road i would close. it has no facilities , very narrow and warped platforms , an odd island platform design which restricts speed through the area and is overall in the worse condition of the two.

 

[BlueLeanie]

No chance. It takes 18 minutes to get to Northolt Park Jn.

If the line were electrified, with swift accelerating stock procured, what kind of difference would that make to the 18 minutes?

 

[Zomboid]

I think that Sudbury Hill Harrow would be the best contender to keep. It has much nicer shelters , much wider platforms and is closer to the Piccadilly line then Sudbury and harrow road.
Sudbury hill harrow would also be easier to put loops on as it
retains it's original platforms , although somewhat overgrown.

Sudbury and harrow road i would close. it has no facilities , very narrow and warped platforms , an odd island platform design which restricts speed through the area and is overall in the worse condition of the two.

I say "effectively" because legally it might be more sensible to do a Pilning and serve it once a week, which would mean leaving it there. But S&HR is the one I'd close because it has a much worse interchange with the Piccadilly line.

If the line were electrified, with swift accelerating stock procured, what kind of difference would that make to the 18 minutes?

Possibly 1 minute at best.
The other question would be where to put the inevitable up loop. If we're 4 tracking between the Ruislip stations, would that be enough?

And how far out would the xx00 (overtaken near South Ruislip by the xx11) get before being caught by the xx26 fast?

In terms of departures I guess MYB could look something like:
xx00: High Wycombe Slow
xx06: Aylesbury via Amersham
xx11: Oxford (fast to Wycombe)
xx15: West Ruislip slow
xx26: Birmingham fast (first stop Bicester)
And the same again for the next 30 minutes, with maybe some tweaks to the fast train stopping patterns, such as the xx56 serving Wycombe.

Old Oak Common could be served by something running in the slow path (that could actually run a bit faster, I doubt Denham golf club needs 4tph to anywhere) that would be a continuation of the xx15, maybe to Aylesbury via Princes Risborough or Gerrard's Cross.

Or perhaps the xx00 Wycombe slow could actually be to Gerrard's Cross and the OOC train would be semi fast to GC and then slow to Wycombe/ Aylesbury.

All we need is a large budget and some credible evidence to suggest that there's a market!

 

[SynthD]

What growth in passenger numbers do you expect from raising service to 4tph? I think it's so low it wouldn't equal out the disadvantage of the loops, let alone the other costs listed above.

is Marylebone really a particularly attractive terminus?

In platform count, yes.

What would South Ruislip junction look like if it was four track, with two track access towards Greenford, plus the line to the waste site?

Before covid, Chiltern was on a 20 minute cycle, rather than todays 30 minute. Does this proposal fit in 20m too?

 

[BlueLeanie]

Is four-tracking the right way to proceed?

Ie, would there be an advantage to offset the passing loops (or relief platform). Say a Northbound relief platform and loop at Sudbury, and a Southbound relief Platform and loop at High Wycombe?

(Or your choice of better suited locations).

 

[HSTEd]

In platform count, yes.

Well if the Old Oak common site can accomodate sufficient platforms to run the non via Amersham service, the platform count advantage at Marylebone becomes much less important.

Does anyone know if the OOC Chiltern terminus concept has a proposed number of platforms associated with it?

 

[The Planner]

Well they only run 4 fasts an hour!

Would need tweaking for the peak to be fair.

So no room for growth then in the future as you have fixed the timetable in stone. 2 Birmingham and 2 Oxford, nothing else.

== Doublepost prevention - post automatically merged: 1 Jun 2025 ==

Well if the Old Oak common site can accomodate sufficient platforms to run the non via Amersham service, the platform count advantage at Marylebone becomes much less important.

Does anyone know if the OOC Chiltern terminus concept has a proposed number of platforms associated with it?

2 maximum.

 

[Harpo]

It is 3 minutes and you would be looking at a 5 minute dwell at a station.

I’ll take being a minute out. Hope you’re not planning on running on yellows.

Any late running by either train would immediately export to the other one - unless of course that lengthy dwell gets extended even further.

 

[The Planner]

I’ll take being a minute out. Hope you’re not planning on running on yellows.

Any late running by either train would immediately export to the other one - unless of course that lengthy dwell gets extended even further.

That assumes coming out two minutes after the non-stopper. Pretty standard.

 

[Zomboid]

Presumably it might emerge on a yellow, but the acceleration of the stopper vs the fast train clearing sections faster means it'll be on greens after a signal or two.

 

[Mgameing123]

Well if the Old Oak common site can accomodate sufficient platforms to run the non via Amersham service, the platform count advantage at Marylebone becomes much less important.

Does anyone know if the OOC Chiltern terminus concept has a proposed number of platforms associated with it?

Old Oak Common station needs to wait until HS2 Euston is complete or because the Elizabeth Line will struggle with the passenger loads from HS2.

 

[The Planner]

Old Oak Common station needs to wait until HS2 Euston is complete or because the Elizabeth Line will struggle with the passenger loads from HS2.

What? OOC will open first, its not waiting for Euston.

 

[NCT]

By ordinary standards the corridor isn't a wasteland, but it's all fairly low density with little to no development potential. Almost every station has a higher frequency alternative a short bus ride away. In this specific context the problem statement likely isn't sufficient strong for the cost associated of the kind of solution desired. A standardised 2tph stopper overtaken at South Ruislip westbound and West Ruislip eastbound without undue impact on faster services is probably the best that can be expected. Making Wembley Stadium 'match day capable' will most likely remain on the 'nice idea on paper but ...' pile.

 

[Zomboid]

What? OOC will open first, its not waiting for Euston.

I think the point was Chiltern OOC should wait until HS2 Euston opens. And I can see the justification, crossrail is going to have a lot of heavy lifting to do when HS2 starts operating at OOC.

Though on the other hand, Chiltern would contribute to getting people to/ from OOC, as well as potentially adding to the load on Crossrail - I guess which way the scales would tilt will depend on where the Chiltern services go.

 

[The Planner]

I think the point was Chiltern OOC should wait until HS2 Euston opens. And I can see the justification, crossrail is going to have a lot of heavy lifting to do when HS2 starts operating at OOC.

Though on the other hand, Chiltern would contribute to getting people to/ from OOC, as well as potentially adding to the load on Crossrail - I guess which way the scales would tilt will depend on where the Chiltern services go.

Ah. Chiltern OOC isn't committed yet anyway. Its passive provision as there certainly isn't a design to solve South Ruislip and Greenford yet.

 

[Sad Sprinter]

From an enthusiasts perspective I’d reopen all the passing loops. Hugely depressing to see a massive gap between the lines.

 

[Bald Rick]

From an enthusiasts perspective I’d reopen all the passing loops. Hugely depressing to see a massive gap between the lines.

If that is the sort of thing that you find hugely depressing, I’d seek help.

 

[Sad Sprinter]

If that is the sort of thing that you find hugely depressing, I’d seek help.

Welcome to people having an interest in something.

 

[Bald Rick]

Welcome to people having an interest in something.

My apologies.

I couldn’t tell (and still can’t) whether you are using ‘hugely depressing’ as an exaggerated emotive figure of speech, or how you truly feel. My comment was based on the latter.

 

[Dr Hoo]

I had always been under the impression that by the Network Southeast era both stations were suffering from earthworks problems (one on an embankment and one in a cutting). It made sense to re-site the platforms ‘in the middle’ rather than have them ‘disappearing down the bank/under a landslip’. With no operational need for loops at the time it wasn’t a difficult decision.

 

[Sad Sprinter]

My apologies.

I couldn’t tell (and still can’t) whether you are using ‘hugely depressing’ as an exaggerated emotive figure of speech, or how you truly feel. My comment was based on the latter.

That's okay, I'll be clearer in the future. I do find it genuinely poignant, but not actually hugely depressing, that would be a cause of concern.

 

[150219]

I had always been under the impression that by the Network Southeast era both stations were suffering from earthworks problems (one on an embankment and one in a cutting). It made sense to re-site the platforms ‘in the middle’ rather than have them ‘disappearing down the bank/under a landslip’. With no operational need for loops at the time it wasn’t a difficult decision.

Yes, you are correct. Sudbury Hill specifically is constrained by embankment supports, especially on the up approach from South Harrow Tunnel. Drainage is an issue there too, but that's not a new problem. I've been told of stories with a 115 storming around the curve from South Harrow Tunnel and finding the landscape under water.