Chiltern Mainline Upgrades post TPE Mk5As

[D365]

Also with the line initially terminating at Old Oak Common you probably need the goodwill/traffic from the Chilterns to boost the ridership to something reasonable.

Other than the mooted bay platforms at OOC. What common ground does speculative enhancements to the Chiltern routes have with HS2?

 

[The Planner]

And all the road disruptions and the extra construction traffic and making a whole swathe of countryside ugly while they are doing it.

I mean you really really can. It’s not like they won’t also stand on their merits.

Also with the line initially terminating at Old Oak Common you probably need the goodwill/traffic from the Chilterns to boost the ridership to something reasonable.

It doesnt work like that. Chiltern will only get upgraded on its merits and business case. The fact they are getting Mk5s and not new stock tells you that. You could argue that the Leamington to Cov line and Cov corridor should get the same treatment. They won't.

 

[BerkshireRails]

And all the road disruptions and the extra construction traffic and making a whole swathe of countryside ugly while they are doing it.

I mean you really really can. It’s not like they won’t also stand on their merits.

Also with the line initially terminating at Old Oak Common you probably need the goodwill/traffic from the Chilterns to boost the ridership to something reasonable.

I struggle to see how Old Oak Common would be effectively operated, because you will have a flat junction or a rather steep flyover unless you raised the fasts on a viaduct over the junction.

 

[MatthewHutton]

Other than the mooted bay platforms at OOC. What common ground does speculative enhancements to the Chiltern routes have with HS2?

Given the HS2 service is going to initially terminate at Old Oak Common outside central London the initial ridership is likely to be disappointing - especially given the unprecedented distance without any stations going through a populated area.

Do not forget the current service is boosted to something reasonable by people travelling between the intermediate stops which adds up as there are lots of station pairs. HS2 won’t have that.

== Doublepost prevention - post automatically merged: 10 Aug 2025 ==

It doesnt work like that. Chiltern will only get upgraded on its merits and business case. The fact they are getting Mk5s and not new stock tells you that. You could argue that the Leamington to Cov line and Cov corridor should get the same treatment. They won't.

Chiltern has a pretty strong business case in general. It has the fifth lowest subsidy per passenger kilometre.

 

[BerkshireRails]

It doesnt work like that. Chiltern will only get upgraded on its merits and business case. The fact they are getting Mk5s and not new stock tells you that. You could argue that the Leamington to Cov line and Cov corridor should get the same treatment. They won't.

I would disagree, I would say it was probably more of a way of quickly getting the desperately needed capacity rather than waiting 5-10 years for the new trains to arrive. Before any new MUs are ordered for Chiltern you need to devise a way of decarbonsiation of the route. Hence, I suggest full electrification with a project like the Transpennine Route Upgrade, but for Chiltern.

 

[NCT]

What desperately needed capacity? Are Chiltern trains full and standing?

 

[MatthewHutton]

What desperately needed capacity? Are Chiltern trains full and standing?

Yes. Even on weekends.

They have two trains in the top 10 busiest in the country - https://www.gov.uk/government/stati...weekdays-in-major-cities-in-england-and-wales

 

[BerkshireRails]

What desperately needed capacity? Are Chiltern trains full and standing?

Yeah to the point that you can’t even get on an 8 coach 165 off Peak.

 

[D365]

Given the HS2 service is going to initially terminate at Old Oak Common outside central London the initial ridership is likely to be disappointing - especially given the unprecedented distance without any stations going through a populated area.

Do not forget the current service is boosted to something reasonable by people travelling between the intermediate stops which adds up as there are lots of station pairs. HS2 won’t have that.

You haven’t answered my question.

 

[MatthewHutton]

You haven’t answered my question.

Certainly in terms of speculation it is perfectly reasonable to assume that HS2 will be forced into following international norms and have at least one stop between London and Birmingham. In order to make that a success the Chiltern service will need to take that into account.

It will also benefit HS2 (and chiltern) with additional traffic and will generate at least some goodwill for HS2 which is sorely needed.

It is also certainly very reasonable for Chiltern to be given some level of priority for future upgrades given the disruption the region has suffered. It’s not like most of the projects that are done are done on a pure business case anyway. A lot of them are about levelling up which is good.

And yes the Chiltern mainline was upgraded to 100mph running in the 2000s - but that was paid for by season ticket holders on a commercial basis and not the state.

 

[BerkshireRails]

Certainly in terms of speculation it is perfectly reasonable to assume that HS2 will be forced into following international norms and have at least one stop between London and Birmingham. In order to make that a success the Chiltern service will need to take that into account.

It will also benefit HS2 (and chiltern) with additional traffic and will generate at least some goodwill for HS2 which is sorely needed.

It is also certainly very reasonable for Chiltern to be given some level of priority for future upgrades given the disruption the region has suffered. It’s not like most of the projects that are done are done on a pure business case anyway. A lot of them are about levelling up which is good.

And yes the Chiltern mainline was upgraded to 100mph running in the 2000s - but that was paid for by season ticket holders on a commercial basis and not the state.

It looks it was the plan that HS2 would make at least one stop between London Euston and Birmingham Curzon Street.*Credit = Rail Engineer

 

[MatthewHutton]

It looks it was the plan that HS2 would make at least one stop between London Euston and Birmingham Curzon Street.View attachment 186069*Credit = Rail Engineer

It’s still 150km or so from Old Oak Common to Birmingham Interchange going through a populated area. No one else has high speed lines with such a stopping distance unless they are basically going through empty countryside.

 

[A S Leib]

It’s still 150km or so from Old Oak Common to Birmingham Interchange going through a populated area. No one else has high speed lines with such a stopping distance unless they are basically going through empty countryside.

How many cases of a high speed line running for 150km with intermediate stops also have a line with two end-to-end trains per hour to one side of it and a line with 5tph on the other?

 

[MatthewHutton]

How many cases of a high speed line running for 150km with intermediate stops also have a line with two end-to-end trains per hour to one side of it and a line with 5tph on the other?

Typically high speed lines are built because there is insufficient capacity on the existing mainline - so with those traffic numbers who knows, but certainly they will have been high traffic almost by definition.

In terms of the Chiltern mainline you can see from the ORR data that from Leamington Spa that only 20% or a little more of passengers go to London, so if we assume it’s the same from Solihull and Dorridge there are maybe as many as 450k passengers a year going to London from those stations. Maybe as many as 2/3rds of those passengers will travel into Birmingham and out again for a shorter trip time? It’s not going to reduce Chilterns ridership to London by much - especially when no one going anywhere but London can plausibly use HS2 as it stands, and where from Warwick Parkway and further south the trip time with HS2 to London won’t be quicker.

From Birmingham Moor Street to London maybe there are as many 750,000 trips a year which is what Solihull the top pair gets, but on the other hand everyone is travelling on price. Perhaps if HS2 has cheaper fares than Avanti they will switch, or perhaps the speed improvement will be sufficiently strong to be worth it.

All in all the business case isn’t going to be affected much by HS2 as it stands but there will be more impact if there is a stop, but on the other hand there will be more connecting trips so thats the trade off.

 

[The Planner]

I would disagree, I would say it was probably more of a way of quickly getting the desperately needed capacity rather than waiting 5-10 years for the new trains to arrive. Before any new MUs are ordered for Chiltern you need to devise a way of decarbonsiation of the route. Hence, I suggest full electrification with a project like the Transpennine Route Upgrade, but for Chiltern.

Full electrification won't be happening. It will be discontinuous and at the south end.

 

[BerkshireRails]

Full electrification won't be happening. It will be discontinuous and at the south end.

This is a future and not the future. Hence full electrifaction is one future and Discontinuous electrifaction is another future.

 

[SynthD]

Reinstating station loops is far from quad tracking. As the current rail suggests, the line narrowed west of Wembley. Last I heard on reinstating the middle lines in High Wycombe, it would slow down the non stopping trains. That can also be fixed with demolishing seized homes, but probably at a greater quantity than the full HS2 plan.

Why? Chiltern itself hasn't been massively disrupted by it. The only interactions have been at West Ruislip and south of Wendover on the Met. You can't justify upgrades just because a separate project has inconvenienced potentially non rail users.

HS2 has built one road and made provision for another near Aylesbury, as that’s what the area wants.

Other than the mooted bay platforms at OOC. What common ground does speculative enhancements to the Chiltern routes have with HS2?

That depends on what traffic you’re focusing on. The long distance travel, ie Stratford/Warwick/Oxford, will still want their fasts. Do you say that post Hs2 they are out of luck as it’s not a line for end to end travel? Or is it better to keep those fasts. The plans at the start of this thread achieve both and then some.

I struggle to see how Old Oak Common would be effectively operated, because you will have a flat junction or a rather steep flyover unless you raised the fasts on a viaduct over the junction.

Which junction are you thinking of? The Chiltern OOC station would be a terminus on the west side of OOC Lane. You could come up with a new Ruislip junction that serves the mainline, the New North Main Line to OOC, and the waste site.

 

[Bletchleyite]

That depends on what traffic you’re focusing on. The long distance travel, ie Stratford/Warwick/Oxford, will still want their fasts.

Oxford has fasts. They run on the GWML. It doesn't need a second set; the Chiltern services are about connectivity and are better as local services.

 

[A S Leib]

Of course Northampton's much larger and benefits by being on a budget route from London to the West Midlands, but, given that Aylesbury to London takes around the same length of time as Northampton for two-thirds of the distance, does it need faster services?

I don't know how feasible a service skipping more stops would be. I can't see having fewer than 2tph between Amersham and Stoke Mandeville being popular; could a nonstop Amersham to Aylesbury service fit between them?

51 minutes (17:30 nonstop Marylebone to Great Missenden) looks like it's currently the fastest Marylebone to Aylesbury; given 33+ minutes for Marylebone to Princes Risborough (High Wycombe only) and 12(? if nonstop) for Princes Risborough to Aylesbury, I don't think massively faster times are currently possible.

 

[Bletchleyite]

Of course Northampton's much larger and benefits by being on a budget route from London to the West Midlands, but, given that Aylesbury to London takes around the same length of time as Northampton for two-thirds of the distance, does it need faster services?

I don't know how feasible a service skipping more stops would be. I can't see having fewer than 2tph between Amersham and Stoke Mandeville being popular; could a nonstop Amersham to Aylesbury service fit between them?

To be honest I see no reason why the Chiltern Met service should stop between Amersham and Harrow on the Hill at any time. Those stations are served perfectly well by the Metropolitan Line, and aside from HotH people don't often alight at these stations coming from the Aylesbury direction/join it towards Aylesbury. HotH is heavily used for interchange with the Tube so would benefit from more stops.

I would make it an hourly (half hourly on weekdays plus some peak extras as now) perfect clockface service calling at all stations between Vale Parkway/Aylesbury and Amersham inclusive, then all trains to call at HotH (pick up/set down only) and Marylebone. This might allow a reduction in stock used to allow strengthening/reduced overcrowding.

 

[A S Leib]

To be honest I see no reason why the Chiltern Met service should stop between Amersham and Harrow on the Hill at any time. Those stations are served perfectly well by the Metropolitan Line, and aside from HotH people don't alight at these stations coming from the Aylesbury direction.

I would make it an hourly (half hourly on weekdays plus some peak extras as now) perfect clockface service calling at all stations between Vale Parkway/Aylesbury and Amersham inclusive, then all trains to call at HotH (pick up/set down only) and Marylebone. This might allow a reduction in stock used to allow strengthening/reduced overcrowding.

Is 4tph between Amersham and Aldgate still an aim of the 4 Lines Modernisation? If Chalfont & Latimer, Chorleywood and Rickmansworth have an even off-peak ten-minute service, taking away the Chiltern service probably wouldn't be as unpopular.

Would calling at Moor Park in place of R-C-C&L help? It might only save a net four minutes to Aylesbury compared to current times, but improve Watford to Aylesbury journeys without needing to introduce extra services (and when Arriva have shown such little interest in doing so).

 

[The Planner]

HS2 has built one road and made provision for another near Aylesbury, as that’s what the area wants.

That is a road, not a railway upgrade as was suggested. I'd also argue that the Stoke Mandeville bypass and Aylesbury link roads were planned regardless and it was a bonus for Bucks county council. They are clearly to enable housing development.

 

[Bletchleyite]

Would calling at Moor Park in place of R-C-C&L help? It might only save a net four minutes to Aylesbury compared to current times, but improve Watford to Aylesbury journeys without needing to introduce extra services (and when Arriva have shown such little interest in doing so).

With the timings so slow anyway I'm not sure they would concern me too much - anyone in a hurry will just drive to Tring. I just find that the stopping services are carrying passengers that the Met could perfectly well carry and have plenty of capacity for, which is wasting rolling stock (on longer trains)/causing overcrowding (when a 2-car is wheeled out in the peak). Having a consistent pattern would probably allow an all day 3 car service with some peak runs strengthened to 5. It would also allow, in the future, a potential move to fixed formation 4x24m stock all day.

These trains only really need to carry passengers between Vale Parkway-Great Missenden inclusive to/from London (in which I include HotH because it's a better Tube interchange for many). Amersham is probably acceptable "collateral damage" for improved interchange with Met stations. I can see the argument for Moor Park for Watford (perhaps also pick up/set down only to keep MP-London pax on the Met) but I struggle with the others.

 

[BerkshireRails]

Of course Northampton's much larger and benefits by being on a budget route from London to the West Midlands, but, given that Aylesbury to London takes around the same length of time as Northampton for two-thirds of the distance, does it need faster services?

I don't know how feasible a service skipping more stops would be. I can't see having fewer than 2tph between Amersham and Stoke Mandeville being popular; could a nonstop Amersham to Aylesbury service fit between them?

51 minutes (17:30 nonstop Marylebone to Great Missenden) looks like it's currently the fastest Marylebone to Aylesbury; given 33+ minutes for Marylebone to Princes Risborough (High Wycombe only) and 12(? if nonstop) for Princes Risborough to Aylesbury, I don't think massively faster times are currently possible.

That train has caught up with Train 422D the 16:54 Aldgate to Amersham, on the approach to Amersham. It would arguably be better to run fast via Princes Risborough than Harrow. It is currently 4tph in the peaks and 2tph off-peak, I am suggesting a 4tph stopper all day, so that each service is less overcrowded as well as all trains would be 100-120m long. Also it might be better not to run to Northampton directly from London Marylebone because of the better connections at London Euston and Old Oak Common compared to London Marylebone. Running fast between London Marylebone and Great Missenden only saves 6 minutes according to the Metropolitan Working timetable.

To be honest I see no reason why the Chiltern Met service should stop between Amersham and Harrow on the Hill at any time. Those stations are served perfectly well by the Metropolitan Line, and aside from HotH people don't often alight at these stations coming from the Aylesbury direction/join it towards Aylesbury. HotH is heavily used for interchange with the Tube so would benefit from more stops.

I would make it an hourly (half hourly on weekdays plus some peak extras as now) perfect clockface service calling at all stations between Vale Parkway/Aylesbury and Amersham inclusive, then all trains to call at HotH (pick up/set down only) and Marylebone. This might allow a reduction in stock used to allow strengthening/reduced overcrowding.

1tph doesn't cut it off-peak, it really needs to be a minimum of 2tph all day and ideally 4tph all day.

 

[A S Leib]

Also it might be better not to run to Northampton directly from London Marylebone because of the better connections at London Euston and Old Oak Common compared to London Marylebone.

I wasn't suggesting doing that; just pointing out that even compared to Northampton, itself somewhere seen as having relatively slow London services, Aylesbury to London isn't particularly fast.

 

[Bletchleyite]

1tph doesn't cut it off-peak, it really needs to be a minimum of 2tph all day and ideally 4tph all day.

4tph isn't justified aside from a few peak extras. It's a glorified country branch line with relatively little leisure traffic. I can see the case for 2tph as it once was, but not more. It's perhaps comparable to Uckfield/East Grinstead but without everyone piling on at East Croydon?

== Doublepost prevention - post automatically merged: 11 Aug 2025 ==

I wasn't suggesting doing that; just pointing out that even compared to Northampton, itself somewhere seen as having relatively slow London services, Aylesbury to London isn't particularly fast.

That can't ever be solved because of the low speeds on the Met. It runs much quicker north of Amersham (though I don't know the actual speeds).

 

[A S Leib]

That can't ever be solved because of the low speeds on the Met. It runs much quicker north of Amersham (though I don't know the actual speeds)

Open railway map says 70 mph between Amersham and Aylesbury (~30 mph through the station and 60 mph to Vale Parkway).

 

[BerkshireRails]

Having a consistent pattern would probably allow an all day 3 car service with some peak runs strengthened to 5. It would also allow, in the future, a potential move to fixed formation 4x24m stock all day.

Ideally it should be able to fit in all platforms at London Marylebone which will require the unit to be under 115m to fit in platform four.

Open railway map says 70 mph between Amersham and Aylesbury (~30 mph through the station and 60 mph to Vale Parkway).

Open Railway Map is reporting the loco hauled max speed of 70mph however Units can do 75mph according to the sectional appendix.

 

[Bletchleyite]

Ideally it should be able to fit in all platforms at London Marylebone which will require the unit to be under 115m to fit in platform four.

4 x 24 = 96.

However, 4 tends to be used for the innersuburban local service anyway.

 

[BerkshireRails]

4 x 24 = 96.

However, 4 tends to be used for the innersuburban local service anyway.

It was mainly in reference to the 5 car service would that be using 20 or 24m long coaches?