125mph Chiltern Mainline - Possible?

[ChilternHenry]

Currently top speeds on the line are 100mph thanks to Evergreen 3. But is there the potential to increase line speeds, to say 110/125mph in places, and in effect, create a line that can seriously compete to WCML between at London and Birmingham.

I am aware high speeds will be virtually impossible until passed Wembley, but how much work would need to be done on present infrastructure to further accommodate higher speeds?

I am aware this may be considered a pipeline dream, and yes, as my name suggests, I am probably oblivious to some major flaws in my argument due to my love of this route. But please, feel free (indeed I encourage you) to point out any such flaws, such as the limited capacity of a predominantly 2 track mainline.

Just to make clear, I'm by no means suggesting every mile of track needs to be 100mph+, but is there the possibility that enough 100mph+ running could be achieved to actually have quicker journey times between Birmingham and London than the WCML.

Could this be an Evergreen 4 when the line is finally electrified, say CP6/7? Just thought this might be better than spending all that money on HS2, although I admit, wouldn't bring the all the benefits that HS2 is proposing.

I am assuming in this thread that expansion of Marylabone is possible, and maybe re-double tracking the 'New North Mainline,' to run some trains from Paddington (providing Crossrail creates adequate paths for new services into Paddington).

 

[mrmartin]

The 125mph linespeed wouldn't make a huge difference. It's due to the amount of stops the Chiltern train takes vs Virgin.

If it was non-stop you'd probably be able to get it down to about 1h20 with some very rough calculations.

Much like HS2 which even though going at 300-400km/h will only knock about 20 minutes off the fastest 125mph (sorry for the unit muddle) VT service. It takes a hell of a long time to accelerate and a similar amount to decelerate, which means you don't spend much time at top speed.
--- old post above --- --- new post below ---
Also, another point would be that I'd imagine the electric Virgin pendos accelerate significantly faster than the diesel chiltern services - electrification would knock a fair whack off the journey time even if the top linespeed stays the same.

 

[Simon11]

Interesting question, which route is quicker by mileage chiltern or wc route?

Then how long would it take if the chiltern had pendos and the route being electrified? Would it be quicker than wc?

 

[ChilternHenry]

Interesting question, which route is quicker by mileage chiltern or wc route?

Then how long would it take if the chiltern had pendos and the route being electrified? Would it be quicker than wc?

I believe the Chiltern line is more direct and the shorter, not 100%

Cascaded pendos may indeed help, but for that does track need upgrading significantly more than it would do for just higher running speeds? I don't know where I'm getting that from, just seems to ring a bell in my head.

 

[LNW-GW Joint]

With just a 2-track line you would end up with less capacity overall, and it would impact the stopping patterns.
Although the newer sections are quite straight, I don't think it would be easy to get 125mph through the older bits (eg around High Wycombe).
The line north of Aynho is still basically a 90mph line and is quite bendy in places with some poor structures (eg a mile of 75mph north of Fenny Compton).
There's just the odd bit of 100 north of Hatton.
Something better might have been achieved if TASS had been fitted for the Voyagers as originally planned, but they gave up.

Edit:
Euston to New St is 113 miles (few chains less).
Marylebone to Snow Hill is 112 miles.
Paddington to Snow Hill is 110.5 miles via Greenford.

 

[Roverman]

Spooky you bring this up, read my Chiltern Report in the VT Untouchable thread!!

 

[Sidious]

Interesting question, which route is quicker by mileage chiltern or wc route?

by 'quicker by mileage' so you mean 'shorter'?

The Chiltern route is 4 miles shorter: New Street to Euston is 115 1/4 miles and Moor Street to Marlebone is 111 1/4.

 

[LNW-GW Joint]

by 'quicker by mileage' so you mean 'shorter'?
The Chiltern route is 4 miles shorter: New Street to Euston is 115 1/4 miles and Moor Street to Marlebone is 111 1/4.

The Euston mileage you quote (Table 66 in the NRT) is via Northampton.

 

[Clip]

Would be better if they 4 tracked some areas where there used to be 4 tracks and increases paths I reckon.

 

[ChilternHenry]

Spooky you bring this up, read my Chiltern Report in the VT Untouchable thread!!

Read your post and you make some good points about value for money to speed ratio as it were. I believe with more work you could defenitely close the time difference a bit more. Also, for reference, I got an advance single, from Marylabone to Moor Street, the day before travel, for £6 (this was summer 2012). I don't know what the Virgin equivalent would be of this, but are there any reasons as to why Chiltern Mainline is by far the cheaper?

I'd also agree with Clip, 4 tracking is a must, including remodeling of Gerrards Cross to its original layout which included 2 through lines, through lines at Beaconsfield, possibly through lines, or a bi di through line at Wycombe, re instatment of both through lines at Risboroughand biscester north, Banbury station remodeling, and old 4 track running re instated at Birmingham end and Solihull area, as well as Ruislip area and Wembley through lines re instated if possible

 

[Clip]

Read your post and you make some good points about value for money to speed ratio as it were. I believe with more work you could defenitely close the time difference a bit more. Also, for reference, I got an advance single, from Marylabone to Moor Street, the day before travel, for £6 (this was summer 2012). I don't know what the Virgin equivalent would be of this, but are there any reasons as to why Chiltern Mainline is by far the cheaper?

I done that back in december too - great value.. London Midland have the same price. Its all about yeild management - if the trains are going anyway and theres a chance they may cart empty air around then best to claw some money back from the service.

 

[Cherry_Picker]

Just going by a gut feeling of driving over the route for quite a few years, I dont think it would be easy to get to 125 at all. Ardley (nr Aynho jn) to Princes Risborough is fairly straight, though there are quite a few underbridges which would probably need strengthening and Beaconsfield to the Ruislips is straight too. You might have to have some 110 or 100 sections around the former Ashendon Junction and from South Ruislip to Wembley but the big problems are it is a two track railway and it is very difficult to expand in places, especially on the London side of the Ruislips. Being able to physically achieve 125mph is quite different to being able to run a functioning railway over it.
Most of the section between Willsden and Marylebone is elevated on viaducts so not much will happen there but the big problem is just catching up stopping services because the track capacity is so much lower than the WCML.

In my opinion the biggest improvement that could be made now is to get rid of all 75mph stock in the fleet. If you could time everything to 100mph class 172s then not only would the local journey times at the south end of the line improve somewhat, but you would be able to pinch a few minutes on quite a few of the mainline services coming in from the Midlands too. Cant see it happening any time soon for financial reasons, but running 75mph trains on a 100mph line is a big bottleneck at the moment.

 

[Clip]

I'd also agree with Clip, 4 tracking is a must, including remodeling of Gerrards Cross to its original layout which included 2 through lines, through lines at Beaconsfield, possibly through lines, or a bi di through line at Wycombe, re instatment of both through lines at Risboroughand biscester north, Banbury station remodeling, and old 4 track running re instated at Birmingham end and Solihull area, as well as Ruislip area and Wembley through lines re instated if possible

Im not sure the tunnel by GX is big enough to have 4 tracks through it is it? Plus rebuilding the platform space by the embankment would be a bit of a challenge whilst still trying to provide a service - it does get very busy there in the morning peaks.

 

[Cherry_Picker]

The tunnel at GX can be four tracked easily. Either side of that tunnel there are quite a few problems, including a huge viaduct over the M25.

 

[ChilternHenry]

The viaduct may indeed need strengthening, or you could even replace it with a shiny new one if you could splash the cash. My extensive list of four tracking and through lines was there to tackle the problem of 75mph stock, you can stick 'em in a loop and let a fast pass. The tunnel at gx was future proofed against returning to the original station layout I believe. This is certainly a route to keep monitoring, what with east west rail, oxford through services, possible re instatment of Uxbridge highstreet branch (and eventual reopening of line to rugby, albeit not strictly Chiltern mainline but related, however I think this would be very long term, and not sure if its actually worth considering at all).

 

[mr_jrt]

My proposal for achieving something like this was to send Crossrail's 2nd branch up the NNML to High Wycombe/Princes Risborough/Oxford/Bicester, with four tracks to at least High Wycombe. Additionally, either a new branch from the Jubilee at Neasden with four tracks restored where possible (and tunnels elsewhere), with the new branch providing the stopping service, enabling Chiltern to sail through. Chiltern would then only have to stop at High Wycombe, Ruislip, (maybe West Hampstead?) and Marylebone, giving ample opportunity for faster running.

Getting Crossrail to Bicester then only needs some short infill electrification to Kings Sutton and the wires will reach the electric spine. Using some of the freed-up capacity at Marylebone, hand over the Met fast lines north of Harrow and you'll be able to have no-conflict OHLE over the whole of Chiltern's London region.

It's then just a case to argue for Birmingham's suburban services to get wired up and that'll provide Leamington to Birmingham, enabling electric operation all the way between Moor Street and Marylebone.

 

[corfield]

I pass through the GX tunnel frequently - I really dont think it could do quad track, and there is a pre existing bridge at the London end which is clearly 2 track wide only.

I've seen the future proof claim many times but is there any link to where this is officially what was delivered ?

A 3rd bi-di yes but it just doesnt look big enough for 4. Will have to get a photo next time alight there.

I'd like to see the Met line cut back prior to the Joint lines on the Marylebone-Amersham line with the 165s taking over all services on that and ex FGW 165/165s &/or ex LO 172s giving 100mph timetable on the CML. i'd be interested to know what station loops/amount of quad tracking would be needed for a higher intensity Metro service out to High Wycombe plus the fast Oxford/Banbury/Birm services say - as the list in the post above (basically every station) seems excessive.

I did note recently on a trip to Oxford that most/nearly all of the Saunderton-Banbury riute appears to have a 4 track wide land corridor with the embankments very far from the southern fence line - I assume quad tracking was planned at the outset in land purchase. This provision however appears to vanish at any urban or natural chokepoint !

 

[ChilternHenry]

I pass through the GX tunnel frequently - I really dont think it could do quad track, and there is a pre existing bridge at the London end which is clearly 2 track wide only.

there is a picture of the tunnel, which takes the full width of the 4 track corridor. As for the bridge, if you are refering to the one today used from passengers to transfer between palatforms, that is able to accompdate 4 tracks beneath as the station was of a similar set up to Beaconsfield at one point. I'll find a picture. But yes, you have a point, im not sure there is any offical aknowledgement of the futurproofing I referred to

 

[aylesbury]

When Mr Shooter was in charge his stated aim was for electrification to Brum this would provide real savings in time and money.Now that the stated aims of NR are to electrify Didcot Brum this would be a good add on project.Not sure about the Aylesbury branch due to LU to Amersham ,but P Risborough to Calvert would make sense and join up with E W rail to Bletchley.Agree about dmu,s being 100mph this would make for better timetabling and our old units could go to Northern Rail were they are needed.As things are at the moment we have an excellent service with good quality rolling stock and stations,so any improvements can wait until the cash becomes available .

 

[swt_passenger]

I've seen the future proof claim many times but is there any link to where this is officially what was delivered ?

There's an example of 'confirmation' here:

Gerrards Cross tunnel was identified as an early potential obstacle. However research has indicated that the new (“Tesco”) tunnel should be capable of accommodating 4 tracks. The tracks within the tunnel will need to be re-aligned to match the 4 track formation either side of the tunnel.

http://webarchive.nationalarchives....ail/alternativestudy/pdf/railintervention.pdf

...but I've seen it confirmed in a few sources including a Chiltern Q&A as well, which I can't find online. However that report quoted is about putting HS2 alongside Chiltern, so IMHO a normal 125 mph route would probably not be so difficult, as it could be arranged as 'paired by direction' with the fast lines in the centre. HS2 would have been a 'paired by use' arrangement and the station would have had to be repositioned away from the tunnel, with the back of one platform against HS2.

 

[corfield]

I was referring to the road bridge at the London end of the tunnel - went thru again today and still doesnt look big enough ! Plus would rip up a lot of previous Chiltern changes to GX.

I can believe it may do but I've yet to see a post construction evidence as opposed to requirements/desires. If it doesn't that would be a showstopper since it's hardly going to be redone after all that palava getting it built.

I say hand the Aylesbury line to Chiltern, cut back the Met and then it is seperare and can be AC electrified with the CML plus get some speed improvements done in the process.

Could the Chiltern 165s be used in the North given these are quite wide ?

 

[Cherry_Picker]

I was referring to the road bridge at the London end of the tunnel - went thru again today and still doesnt look big enough ! Plus would rip up a lot of previous Chiltern changes to GX.

There are two large viaducts (or bridges if you prefer) a few hundred yards beyond the London side of the tunnel at Gerrards Cross station where the railway crosses major roads. The first crosses the A40, then almost immediately there is a second which crosses the M25. They are both only wide enough for two tracks, and of course the point where the M25 viaduct crosses the motorway is the stretch between the M40, M4 and Heathrow Airport. It is the single busiest stretch of road in the United Kingdom. I think it would be almost impossible to widen given the disruption it would cause.
You can get four tracks inside the tunnel easily though.

 

[corfield]

There is a brick overbride about 15 yards away from the London portal. I think this carries a GX residential road over the cutting - which is quite deep at this point.

Still doesnt look big enough and anyone a link to something authortative ?

 

[cle]

Improvements from Marylebone to Neasden would benefit all services - linespeeds are pretty low when they needn't be.

Beyond that I'd say making as much of it a 4 track railways as possible (at least up to about Bicester) would help - so restoring through lines and platforms to allow overtaking and faster passage.

The next step would be wires and the improvements which come with that, especially when you have more stations. A non-stop journey on diesel is much the same - see HSTs on the ECML to York for example.

 

[swt_passenger]

There is a brick overbride about 15 yards away from the London portal. I think this carries a GX residential road over the cutting - which is quite deep at this point.

Still doesnt look big enough and anyone a link to something authortative ?

Brick road overbridge replacements are standard problems that go away subject to funding.

The 'Tesco tunnel' is the only significant structure, and if the Atkin's (consulting civil engineers to DfT and HS2 Ltd) statement I linked to above isn't authoritative enough for you why not try searching the web yourself... :roll:

 

[mr_jrt]

Removing the bridge over the M25 would do well for streamlining that section, and you could replace it with a new, modern 4-track bridge with fewer spans. I can imagine that building a new bridge would be far more disruptive to the railway than the road, especially given they managed to widen it easily enough.

 

[The Planner]

Beyond that I'd say making as much of it a 4 track railways as possible (at least up to about Bicester) would help - so restoring through lines and platforms to allow overtaking and faster passage.

Doesn't need that much, the issue is stopping services which is only really a constraint to High Wycombe. It wouldn't need any more track from there. If you four tracked to Neasden keeping the two routes separate (DUDU) it would help if there was an increase in services but you are likely to just be importing problems into Marylebones throat and platforms. You could probably get away with two track to South Ruislip and then 4 track from there to Gerrards Cross. I have mentioned previously that you will only get what is needed to run an aspirational timetable, nothing is gold plated anymore.

Aspirations for faster trains, especially on stopping services is only any good if they can actually achieve those higher speeds between stops.

 

[Cherry_Picker]

Removing the bridge over the M25 would do well for streamlining that section, and you could replace it with a new, modern 4-track bridge with fewer spans. I can imagine that building a new bridge would be far more disruptive to the railway than the road, especially given they managed to widen it easily enough.

How much would that cost?

This is the view of the railway viaduct from the M25. It's a significant structure and you would have to have lengthy road closures to do anything with it, would you not?
This is also half a mile or so from Junction 16 of the M25 and unless I am very much mistaken the stretch of the M25 between Jct 16 (M40) and Jct 15 (M4) is the single busiest bit of road in the country because it's also where Heathrow Airport happens to be. Getting permission to close that would be extremely difficult, surely?

Aspirations for faster trains, especially on stopping services is only any good if they can actually achieve those higher speeds between stops.

Indeed. There are plenty of 165 worked services which go Banbury - Bicester - Haddenham - Risborough or Wycombe - Beaconsfield - Gerrards Cross which would be able to do 100mph. 75 is definitely too slow these days, but again, it's all about cost of upgrades. Nothing is going to happen in the next five years, but is it worth spending a lot of cash on faster DMUs in ten years if you think the line might be electrified in fifteen? (numbers pulled out of thin air for the sake of the argument btw)

 

[Manchester77]

Why not do what they've done up here in manchester?
On the M60 and M56 the motorway was closed for one day while they pushed the bridge deck out over the road and onto the supports.
Apply to here by:-
Upgrading the current viaduct and install a new two track viaduct adjacent so four tracks split between two viaducts?

 

[Clip]

Improvements from Marylebone to Neasden would benefit all services - linespeeds are pretty low when they needn't be.

Beyond that I'd say making as much of it a 4 track railways as possible (at least up to about Bicester) would help - so restoring through lines and platforms to allow overtaking and faster passage.

The next step would be wires and the improvements which come with that, especially when you have more stations. A non-stop journey on diesel is much the same - see HSTs on the ECML to York for example.

Bridges wouldnt be a problem as the poster above has said you raise it then remove one and install the other. Haddenham would prove a problem to 4 track wouldnt it? Theres no room left there is there? and with a proposed housing development opposite the station then you are running out of land to 4 track.