Crossrail/Elizabeth Line. From construction to operation - ongoing discussion

[whole diary]

[ellendune]

With all the work to be done around OOC^▸ (Old Oak Common (depot)), perhaps the 6 tracks out of Paddington could also be taken as far out as Ealing Broadway.

Whilst desirable, that wouldn't be possible without a huge amount of money being spent.  The railway goes into a small cutting just after Old Oak Common, then you have the Up and Down Poplar lines coming in, followed closely by Acton Main Line station, then Acton Yard, before the final hurdle of the Central Line gets in the way!

I assume that 6 tracks would at least be taken out to the junction with the WCML^▸ (West Coast Main Line) link.

[IndustryInsider]

Yes, that's where some room exists if you remove the current reception lines (just about).

[onthecushions]

Yes, that's where some room exists if you remove the current reception lines (just about).

The need for 6 tracks out of Paddigton as far West as practicable is because that is where there is the densest traffic and speeds are lowest. There is space but with numerous obstructions as far as Old Oak West Junction, now singled along the old High Wycombe line. To go further West would need another span for the Acton - Willesden line overbridge. Then, there is probably enough room between the fences for 6 tracks + the freight connecting lines but not with graded embankments. While this is all horribly expensive, I am amazed at the heroic Civil works already being constructed for Crossrail. Adding a Herts branch to Crossrail will probably come with a ^1Bn tag and I don't think that Thames Valley up Crossrails standing waiting at Ealing Broadway for a path between crossing Watfords will be acceptable.

We shall see.

OTC

[Btline]

There is no need for extra tracks. The full crossrail service will fit onto 2 tracks east of Paddington, why does it need extra tracks?

This will get done as cheaply as possible!

[4064ReadingAbbey]

There is no need for extra tracks. The full crossrail service will fit onto 2 tracks east of Paddington, why does it need extra tracks?

This will get done as cheaply as possible!

Think about it. The issue is not Crossrail, but services into and out of the Paddington train shed.

Of course Crossrail can run on two tracks - if only Crossrail use them as is the case in the central London tunnels. However there will be residual services from further west of Reading as well as, possibly, one or two remaining through trains from Henley and Bourne End which will use the Relief Lines and run into the Paddington train shed. Westwards from the East and West Junctions at Acton freights are added to the mix which can have knock-on effects on the timekeeping of the Crossrail trains so a certain flexibility is needed.

It is already planned that Crossrail takes over the two tracks on the northern side of the layout from Ladbroke Grove eastwards and these will be connected to the Crossrail tunnels at Royal Oak. Near Portobello Junction there will be a single lead making a flat junction with the Relief Lines forming a line which will feed the higher number platforms in the Paddington train shed. Essentially Paddington will be served by four tracks, the two Main Lines, one parallel track off the Up Main from Ladbroke Grove and the single line from the Reliefs.

The layout I have described will probably just about work as long as half the westbound Crossrail trains terminate at Royal Oak. If Crossrail is extended to Tring then there will be no spare capacity on the Relief Lines at all. Paddington train shed will be serviced only from the Main Lines - there will be no flexibility as the Reliefs will be full of Crossrail trains so if anything untoward happens on the two track section of the Mains, Paddington will stop.

To make the Tring extension work reliably there will need to be two grade separated junctions - one where the two Crossrail routes separate at or near Old Oak Common and the other to separate the Western Crossrail services from the Relief lines somewhere west of the Old Oak Junction mentioned above. I would think this junction would have to be somewhere near Acton Main Line and the Crossrail tracks would be tunnelled under Old Oak to the Junction for Tring. There will have to be six tracks inwards from the 'Acton' junction, two for Crossrail and four serving the Paddington train shed. If this is not done then any hope of using the capacity made available in the Paddington train shed by the diversion of the suburban services, and possibly HEx, into the Crossrail tunnels for use by trains from further out will die. The Mains can support 20 trains an hour, possibly 21, and that's it.

Essentially, if Crossrail simply takes over the Relief Lines as far as Old Oak the choke point on the Western will move from Reading, which has just been expensively extended, to the Paddington throat.

[Electric train]

There is no need for extra tracks. The full crossrail service will fit onto 2 tracks east of Paddington, why does it need extra tracks?

This will get done as cheaply as possible!

Think about it. The issue is not Crossrail, but services into and out of the Paddington train shed.

Of course Crossrail can run on two tracks - if only Crossrail use them as is the case in the central London tunnels. However there will be residual services from further west of Reading as well as, possibly, one or two remaining through trains from Henley and Bourne End which will use the Relief Lines and run into the Paddington train shed. Westwards from the East and West Junctions at Acton freights are added to the mix which can have knock-on effects on the timekeeping of the Crossrail trains so a certain flexibility is needed.

It is already planned that Crossrail takes over the two tracks on the northern side of the layout from Ladbroke Grove eastwards and these will be connected to the Crossrail tunnels at Royal Oak. Near Portobello Junction there will be a single lead making a flat junction with the Relief Lines forming a line which will feed the higher number platforms in the Paddington train shed. Essentially Paddington will be served by four tracks, the two Main Lines, one parallel track off the Up Main from Ladbroke Grove and the single line from the Reliefs.

The layout I have described will probably just about work as long as half the westbound Crossrail trains terminate at Royal Oak. If Crossrail is extended to Tring then there will be no spare capacity on the Relief Lines at all. Paddington train shed will be serviced only from the Main Lines - there will be no flexibility as the Reliefs will be full of Crossrail trains so if anything untoward happens on the two track section of the Mains, Paddington will stop.

To make the Tring extension work reliably there will need to be two grade separated junctions - one where the two Crossrail routes separate at or near Old Oak Common and the other to separate the Western Crossrail services from the Relief lines somewhere west of the Old Oak Junction mentioned above. I would think this junction would have to be somewhere near Acton Main Line and the Crossrail tracks would be tunnelled under Old Oak to the Junction for Tring. There will have to be six tracks inwards from the 'Acton' junction, two for Crossrail and four serving the Paddington train shed. If this is not done then any hope of using the capacity made available in the Paddington train shed by the diversion of the suburban services, and possibly HEx, into the Crossrail tunnels for use by trains from further out will die. The Mains can support 20 trains an hour, possibly 21, and that's it.

Essentially, if Crossrail simply takes over the Relief Lines as far as Old Oak the choke point on the Western will move from Reading, which has just been expensively extended, to the Paddington throat.

Actually to make it work the adoption of ATO^▸ (Automatic Train Operation) (Automatic Train Operation) set the entry / exit past the OOC^▸ (Old Oak Common (depot)) area on both routes even on 2 tracks for sole Crossrail use 24tph is achievable,

[eightf48544]

Won't we also have all singing and dancing ERTMS^▸ (European Rail Traffic Management System.) out Padd by 2019?

[grahame]

Actually to make it work the adoption of ATO^▸ (Automatic Train Operation) (Automatic Train Operation) set the entry / exit past the OOC^▸ (Old Oak Common (depot)) area on both routes even on 2 tracks for sole Crossrail use 24tph is achievable,

And I wonder what's possible with ATO and its future developments on a pair of tracks at high speed

Let's do some simple sums at 100 km per hour, and with train lengths of 250 metres.    Trains would pass in 9 seconds - so if there were 30 trains an hour, the line would be occupied for 270 seconds - that's a 7.5% utilisation.  It's not beyond the realms of possibly that automatic train operation could feedback from one train to another, so that slowing / gap closing could work in patterns of multiple trains not singly.   And let's say we got up to 20% utilisation - that's an awful lot more trains.

Unlikely?   Maybe, in the short and medium term future, but think back to when Paddington first opened - would anyone have every dreamed that it would be safe and feasible to send out trains at a 3 minute headway routinely?   It may come!

Won't we also have all singing and dancing ERTMS^▸ (European Rail Traffic Management System.) out Padd by 2019?

Added while I was writing ... yes as I understand it ERTMS may be a step in that direction

[Electric train]

ATO^▸ (Automatic Train Operation) is being used on Crossrail, in the tunnel sections; Thameslink is setting up ATO for 2018 for its core.  If Crossrail ATO were to be extended to take out to Canal Junction then the 24tph is feasible.

Although ETRMS will not be in place on the GWML^▸ (Great Western Main Line) for 2018 nor will the Crossrail extension to the WCML^▸ (West Coast Main Line) it which ever guise it takes

[ellendune]

There is no need for extra tracks. The full crossrail service will fit onto 2 tracks east of Paddington, why does it need extra tracks?

This will get done as cheaply as possible!

The presently planned service will fit on to the 2 tracks out of pPaddington.  If additional services to the WCML^▸ (West Coast Main Line) are added to this them possibly not.  That is why I enquired whether there was space to add tracks as far as the WCML junction!

[eightf48544]

If Crossrail is ever extended to the WCML^▸ (West Coast Main Line) I would suggest it could easily have it's own two tracks as far as the juction. After all they can then do away with the turnback sidings at Westbourne Park and remove  the "Tourist Platforms" as well as all trains will go through.

[4064ReadingAbbey]

Essentially, if Crossrail simply takes over the Relief Lines as far as Old Oak the choke point on the Western will move from Reading, which has just been expensively extended, to the Paddington throat.

Actually to make it work the adoption of ATO^▸ (Automatic Train Operation) (Automatic Train Operation) set the entry / exit past the OOC^▸ (Old Oak Common (depot)) area on both routes even on 2 tracks for sole Crossrail use 24tph is achievable,

I realise that 24 tph and more is possible on the ATO-equipped Crossrail tracks. The point I was trying to make is that, if the layout is built as currently planned and Crossrail is extended to the WCML^▸ (West Coast Main Line) branching off at Old Oak, then effectively there will be only two tracks for longer distance trains on the Great Western main line from Southall West inwards - the last current Up Relief to Up Main crossing before the Reliefs become dedicated Crossrail tracks. With 24 tph from Old Oak inwards there will be no leeway to be able to use the Reliefs to work round a problem on the Mains without screwing up the Crossrail services and no room for other trains anyway especially if they have to leave the Crossrail tracks via a flat single lead junction to a single line near Portobello.

One may be able to run 24 or 30 trains per hour on the Mains in each direction to serve the train shed using modern cab-signalling, but that is theoretical for trains with identical acceleration and speed characteristics - not everything on the Mains will be SETs^▸ (Super Express Train (now IET)). At this density no trains will be able to make any stops on the mains between Reading and Paddington. That will delight the travellers from Twyford, Maidenhead and Slough... The trains will have originating points ranging from Penzance, Paignton, Carmarthern, Hereford, Bedwyn, Oxford, Weston-Super-Mare and so on and be subject to varying delays on their journeys. It is essential to allow some slack in the timetabling to be able to offer a reliable service.

To get such an intensive timetable to work trains will have to be presented at Reading - the last sensible place where the running order can be changed on a route with tracks paired by use and not direction - within seconds of right time to give them a fighting chance of getting through the two track section into Paddington without causing problems. If outer suburban trains from places like Oxford will still be using the Reliefs to serve stations such as Maidenhead and Slough, they will have to switch to and from the Mains at Southall - and more likely at Stockley Bridge Junction to avoid the Heathrow traffic - as they will no longer fit on the Reliefs from Old Oak inwards. Both are flat junctions...

A few years ago I lived in Munich and saw such a problem at first hand. The S-Bahn passes 30 trains per hour in the peaks (Crossrail, eat your heart out...!) through the tunnels under Munich. There are a series of grade-separated junctions to the west of the Hauptbahnhof as the various branches peel off the pair of S-Bahn tracks. At Laim the route for both the S1 and S2 branches leave the main stretch and then, immediately following, there is another grade separated junction where the S1, for the airport, leaves the S2 for Petershausen. The S1 then made a flat junction with the twin-track DB^» (Deutsche Bahn - German State Railway - about) main line where it shares the tracks along the Isar valley with trains to Landshut, Regensburg and Plattling as far as Neufahrn where it leaves on a grade separated junction for the airport.

Although the traffic density on this main line was not high, there were sufficient trains, both passenger and freight, to upset the timekeeping of the S1 sufficiently often that the trains missed their slots, only some 30 seconds wide, at Laim for inbound trains, and so messed up the intervals and sequencing of trains through the central tunnel. To alleviate this issue yet another grade separated junction was built between Laim and Moosach where the S1 joined the DB's metals.

Having seen the difficulties that operating an intense Crossrail-like service on shared infrastructure can cause, I maintain that unless the Crossrail trains have their own dedicated tracks in those places where the density of Crossrail trains is so high that other traffic cannot be reliably handled, then the reliability not only of the Crossrail service but also that on the main lines will suffer. This means that at least as far out as Old Oak Crossrail trains need their own pair of tracks and both Mains and Reliefs on the Great Western Main Line must continue unbroken through to Paddington. Ideally dedicated Crossrail tracks would extend to Airport Junction for the airport traffic - west of there Crossrail trains run at a lower frequency and so could probably co-exist with the GW^▸ (Great Western) outer-suburban and the freight traffic on the Relief Lines.

[Btline]

Well of course, the sensible thing would be to have no other residual service on the relief lines.

Then Crossrail can take over the relief lines completely (bar a bit of freight).

[4064ReadingAbbey]

Well of course, the sensible thing would be to have no other residual service on the relief lines.

Then Crossrail can take over the relief lines completely (bar a bit of freight).

The effect of that will be that Twyford, Maidenhead and Slough will be served only by all-stations trains to London and any passengers from west of Reading to those stations will have to change at Reading.

Or the toiletless Crossrail trains will have to be extended to Newbury/Bedwyn and/or Oxford.

I can see that going down well.

[IndustryInsider]

I'm wondering how they would link the WCML^▸ (West Coast Main Line) and GWML^▸ (Great Western Main Line) anyway?  As Graham posted on the previous page, it's a short distance, but it is a very 'busy' stretch of land.  Does anyone know what the current thinking is regarding the route it would take?

I'm guessing the current Willesden Down/Up relief lines (which are on the southern side of the WCML in the area concerned, but burrow under the WCML to join the Down/Up Slow lines just before Wembley Central) will be used as crossing the WCML by any other means would be expensive, but would a link line run from the Kensal Green area (which would probably have been ideal had it not been for the massive Kensal Green cemetery using up much of the available land), or will a longer link line be built from somewhere near Old Oak Common to link to the Up/Down Cricklewood line before joining the Up/Down Willesden via an upgraded Up/Down Acton Branch?  Or will a completely new link be built that goes over/under all these various obstructions?

Or are there other possibilities, that won't cost the earth, that I'm missing?