Crossrail bits and bobs

[DynamicSpirit]

Cross-platform interchange between a ~240m long Crossrail train and a 90m long DLR train is a recipe for disaster when things go wrong. Not having that interchange makes it possible to regulate passenger numbers in situations where there are unusually large transfer flows (e.g. if Crossrail were blocked).

If that is the only issue preventing cross-platform interchange, couldn't you solve it by simply having a barrier along the centre of the platform, with regular gates in the barrier? The gates would be left open in normal situations, but could be closed if some need to regulate numbers of passengers interchanging arises.

EDIT: Or - even more simply - do it the way the tube deals with this kind of issue: By simply having trains not call at the station if disruption or other issues mean the station is too crowded. (Yes, I know that's more inconvenient for passengers, but we are presumably talking about unusual situations in which there may already be disruption anyway)

 

[Taunton]

None of this excuses what was done at Custom House. Quite why the quest for step free access means that interchanging passengers have to go up and down two sets of steps to/from the footbridge is not particularly apparent.

I suspect that the remaining stations, with some of the ingenuity shown on the Victoria Line design, could have achieved the same thing while complying with current regulations. There have been innumerable different excuses for the poor Jubilee design - Bermondsey, as a wayside Jubilee station (9m per year and normally feeling deserted), has bigger passage sizes than Oxford Circus (100m per year).

 

[jopsuk]

to achieve what you suggest would have meant rebuilding Prince Regent and Royal Victoria stations as well as entirely rebuilding Custom House. It would have required a flyover at Prince Regent to route the eastbound DLR track over the CR tracks as the tunnel portal is someway to the east. The layout would have required the east bound DLR to be moved to the north side of the formation and CR2 built down the middle.

They took the easy option of building CR2 on the disused trackbed and leaving the DLR relatively unmolested.

 

[rebmcr]

There have been innumerable different excuses for the poor Jubilee design - Bermondsey, as a wayside Jubilee station (9m per year and normally feeling deserted), has bigger passage sizes than Oxford Circus (100m per year).

Oxford Circus regularly has to close its front doors to ease overcrowding.

 

[NotATrainspott]

I think people are also not remembering that these stations have been designed by professional engineers who have access to vastly more information about what does and can happen. Things which might look sensible on the surface might have unseen knock-on effects which result in a worse overall outcome.

For instance, the interchange at Custom House might not be perfect but it's not like it's actually going to deter people who really need to make that change. Conversely, it will deter people who could use it but don't actually need to. That might sound bad but if there are a lot of those people, then they can then cause major problems elsewhere on the DLR. For instance, if your office is closer to a DLR station than a Crossrail station, then the idea of saving a walk by doing a cross platform interchange might be quite enticing. However, the DLR is already busy enough and it's unlikely that people would make that change in the other direction, so the brand new high-capacity Crossrail system would lose a few passengers who would then overload the relatively low-capacity DLR system. The total good done by saving a few passengers a bit of walking to the office would be outweighed by additional problems caused to DLR passengers, who wouldn't have the option of moving to Crossrail.

 

[Bald Rick]

Absolutely true. The rot set in with the Jubilee Extension, and has continued with Crossrail.

Ah yes, all those cross platform interchanges on the Jubilee line between Bond Street and Charing Cross.

If they could be done, they would be.

Anyone is welcome to advise how you would get cross platform interchange between the east-west Jubilee and 2 X north-south lines at Waterloo, or the E-W Jubilee and N-S Northern at London Bridge, or the E-W jubilee at Canada Water and the N-S ELL. Cross platform interchange with the Central on Crossrail was not possible due to the size of the new tunnels and proximity to the surface of the central line. I'll stop now.

 

[Busaholic]

Anyone is welcome to advise how you would get cross platform interchange between the east-west Jubilee and 2 X north-south lines at Waterloo, or the E-W Jubilee and N-S Northern at London Bridge, or the E-W jubilee at Canada Water and the N-S ELL..

Use a doctored compass?

 

[edwin_m]

Bermondsey, as a wayside Jubilee station (9m per year and normally feeling deserted), has bigger passage sizes than Oxford Circus (100m per year).

Not quite sure what you are trying to say here, as Oxford Circus isn't even on the Jubilee Line. It last received major modifications in 1967 with the Victoria Line, being one of the stations where that line achieves cross-platform interchange. The Tube lines of the 60s and 70s and their stations were built mostly to the dimensions adopted for their Edwardian predecessors.

By the time of the Jubilee Extension in the 1990s (and then Crossrail) everything was built on a much grander scale. Modern civil engineering techniques made this more feasible and it was recognised that building big from the beginning was far better than trying to enlarge later. As amply illustrated by Oxford Circus.

 

[Class 170101]

In the short-term, probably. Mid-term, I believe the plan is to make the line part of the Chiltern franchise (operating a High Wycombe to West Ealing service), but this will require new platforms on the NNML at Greenford, along with reinstating the double track from there to South Ruislip.

Why does the double track need re-instating? Chiltern use the line now with four trains per hour (two each way) operated over single track.

 

[MarlowDonkey]

Chiltern use the line now with four trains per hour (two each way) operated over single track.

There's just one Chiltern train a day each way that goes from South Ruislip to Paddington. All other services take the line from South Ruislip to Neasden, which is double track .

A Wycombe to West Ealing service would open up access to Crossrail for passengers from Chiltern stations. It might be a bit on the slow side, if all station stoppers.

At Greenford the existing terminating service has a cross platform interchange with the Central Line. This is at escalator height above the NML.

 

[Taunton]

Passing Custom House station a few days ago, there were two GBRF Class 66 there with a substantial works train. Hadn't realised that main line diesels were now working through the two tunnels under the Thames and under the Royal Docks to get here. The track and pointwork now seems complete, just the overhead to go.

 

[Bald Rick]

Passing Custom House station a few days ago, there were two GBRF Class 66 there with a substantial works train. Hadn't realised that main line diesels were now working through the two tunnels under the Thames and under the Royal Docks to get here. The track and pointwork now seems complete, just the overhead to go.

And the signalling of course.

The train was the concreteing train, laying the slab for the track. Long way to go yet.

 

[Taunton]

The train was the concreting train, laying the slab for the track. Long way to go yet.

This seems a bit of a chicken-and-egg situation, but how can you have a train to lay the slab for the track, given that the train was evidently running on track already in place.

 

[swt_passenger]

This seems a bit of a chicken-and-egg situation, but how can you have a train to lay the slab for the track, given that the train was evidently running on track already in place.

The loco is at the back of the train in its direction of travel when laying concrete, and the concreting is being done at the front. The track elements (special sleepers so the concrete sets round them) have already been positioned and accurately aligned using multipurpose gantries, and various jacks and jigs. There's a video around somewhere showing exactly how it is done, I will try and find it.

Here you are: https://www.youtube.com/watch?v=65ok77gPdXo

Much easier than trying to explain it. Was a bit surprised to see that the rail goes in first, but it is all quite logical; and of course the diesel loco is nowhere near the 'work face'...

 

[Taunton]

Thank you. It's certainly a different scale of things to the old ganger at Taunton long ago calling off two or three Dogfish to be on a siding at Norton Fitzwarren by Friday afternoon ...

Three things I would be grateful for illumination about.

Firstly, this was a huge train with two heavy locomotives at the back. 2,000 tons? Given that it can be operated on the track before the concreting takes place, and that the track is fully levelled and supported by other than the concrete being installed, what additional benefit does the concrete serve ?

Secondly, I am aware that it is presented as a maintenance-free approach compared to ballast, but given the lengthy disruption currently being caused by the closure of the Glasgow Queen Street approach, replacing concreted approach tracks which was laid not that long ago, it seems it is not as permanent a solution as might be presented.

Lastly, having had some involvement with concrete motorway surfacing as opposed to asphalt, although it might have a somewhat longer life and need less routine maintenance, if it does develop any defect it is a sight more challenging and disruptive to repair, and any change to the arrangement of lanes (read installation of points etc) is a way more difficult and disruptive job. Surely Crossrail cannot anticipate lengthy closures like the Queen Street situation when it comes to finally replacing it.

 

[Bald Rick]

Thank you. It's certainly a different scale of things to the old ganger at Taunton long ago calling off two or three Dogfish to be on a siding at Norton Fitzwarren by Friday afternoon ...

Three things I would be grateful for illumination about.

Firstly, this was a huge train with two heavy locomotives at the back. 2,000 tons? Given that it can be operated on the track before the concreting takes place, and that the track is fully levelled and supported by other than the concrete being installed, what additional benefit does the concrete serve ?

Secondly, I am aware that it is presented as a maintenance-free approach compared to ballast, but given the lengthy disruption currently being caused by the closure of the Glasgow Queen Street approach, replacing concreted approach tracks which was laid not that long ago, it seems it is not as permanent a solution as might be presented.

Lastly, having had some involvement with concrete motorway surfacing as opposed to asphalt, although it might have a somewhat longer life and need less routine maintenance, if it does develop any defect it is a sight more challenging and disruptive to repair, and any change to the arrangement of lanes (read installation of points etc) is a way more difficult and disruptive job. Surely Crossrail cannot anticipate lengthy closures like the Queen Street situation when it comes to finally replacing it.

It's not 2000 tonnes, although the axle weight is, I guess 20t which is about double that of the passenger trains that will use it. However most of the weight is at the back of the train (locos, aggregate, mixing plant etc), all that runs over the to be concreted track is some lightweight wagons and a concrete pipe.

There is, of course, one hell of a difference between one train that moves at walking pace and 12 or 24 (or 30) trains per hour at 60mph.

Point 2 an 3 are a fair challenge. I suspect that the slab in Queen Street tunnel has been affected by the water in there, and that it is an old tunnel retrofitted with slab. There is plenty of other slab track around approaching its 40th birthday that is in perfectly good condition. Equally, where slab has had to be removed for gauge reasons (e.g. Ipswich tunnel) it took a Herculean effort to get it out. Given that the Crossrail slab is in brand new tunnel designed to take it, I should imagine it has an asset life measured in centuries.

As an aside, the Chinese have used slab on many of their high speed lines - IIRC one of the longer routes has over 1000km of the stuff.

 

[Taunton]

Thank you again.

I believe the Mersey Loop tunnels, just 40 years old and slab track from the start, are about to have a similar lengthy closure to get the slab dug out and replaced.

Any precautions regarding the diesel fumes from the locos inside the tunnels?

 

[edwin_m]

I think I read somewhere that the concreting train has a long pipe running off the "business end" so that it doesn't have to stand on unconcreted track or indeed track where the previous day's concrete hasn't fully set.

Given that the tunnel itself is concrete, if the track slab cracks it's probably the least of your problems.

 

[swt_passenger]

I think I read somewhere that the concreting train has a long pipe running off the "business end" so that it doesn't have to stand on unconcreted track or indeed track where the previous day's concrete hasn't fully set...

This is what surprised me about taunton's question. The video I linked to explained that the working end consists of a 300m pipe. The locos will get nowhere near the setting concrete for a few days.

There are aspects to the commentary that could be better though, he refers to stage 1 as the rails being 'installed' in the tunnel, it would probably have been better to explain this as being delivered into position in the tunnel so that they can then be lifted sideways onto the sleepers by the multipurpose gantries.

In the condition at stage 2 where the rails are mounted in the sleepers but the alignment is yet to be done, then it seems the sleepers are resting on the cast concrete track bed, and will be safe to run wagons over, (e.g. for sleeper deliveries for the next length), but once it is jacked up into final alignment there will be gaps under the sleepers until the concrete is poured.

 

[Taunton]

OK, I should have said that the train appeared to operate over the track before the concrete had cured, because it was stated that once the concrete is pumped in the train moves forward. Does it do less than 300m per night and not encroach on what was just pumped for a day or more? It seemed a substantial train that I felt held far more raw material than that.

If you are doing an overnight motorway repair there are quick-setting additives for the concrete, but those compromise the concrete strength and quality, and you wouldn't want to use them on something high loadbearing and permanent like this.

 

[swt_passenger]

Last months Modern Railways reported 170 - 180 metres of concrete poured on a good night. That would suggest, given the length of the concrete batching plant part of the train, that the loco itself will take a few days to reach setting concrete?

 

[Bigfoot]

Could it not be obvious that whatever the process is for the laying of the concrete the train/plant is set up to work in the tunnel so to not affect the previous pours? As for fumes, the tunnel are ventilated...

 

[Taunton]

One of the poor design issues of Crossrail is the lack of proper reversing facilities right across the core to handle any disruption to the service. Emergency crossovers seem to be seen as optional extras nowadays, and in any event the old ability to reverse any service efficiently seems to be a lost skill, despite innumerable emergency planning meetings taking up one's diary for months ahead.

Was reminded of this only yesterday when a police incident (actually on the Marylebone line) at Willesden Green apparently led to the suspension of the Jubilee Line for the entire length through to Stratford, it being "too difficult" to arrange a short working point. It really is inappropriate for all the Jubilee's central London usefulness, and the cross-river connections in East London, to be entirely lost because of something that has happened over in Willesden, and surely the same is going to apply to Crossrail.

 

[traji00]

One of the poor design issues of Crossrail is the lack of proper reversing facilities right across the core to handle any disruption to the service. Emergency crossovers seem to be seen as optional extras nowadays, and in any event the old ability to reverse any service efficiently seems to be a lost skill, despite innumerable emergency planning meetings taking up one's diary for months ahead.



Was reminded of this only yesterday when a police incident (actually on the Marylebone line) at Willesden Green apparently led to the suspension of the Jubilee Line for the entire length through to Stratford, it being "too difficult" to arrange a short working point. It really is inappropriate for all the Jubilee's central London usefulness, and the cross-river connections in East London, to be entirely lost because of something that has happened over in Willesden, and surely the same is going to apply to Crossrail.

Much agreed. Ideally Liverpool Street and Paddington would have been built with a reversing siding and/or crossover. Alternatively three tracks (centre for terminating purposes) would have sufficed.
Alas, hindsight...

 

[coppercapped]

Much agreed. Ideally Liverpool Street and Paddington would have been built with a reversing siding and/or crossover. Alternatively three tracks (centre for terminating purposes) would have sufficed.
Alas, hindsight...

But there will be a reversing siding at Paddington - or rather near Westbourne Park where half the westbound trains will terminate.

 

[edwin_m]

Crossrail will be able to use the high level platforms at Liverpool Street and Paddington in the event of disruption on the central section. There are turnback sidings at Westbourne Parks for trains coming from the west to terminate at Paddington and probably extra trains can run to Abbey Wood if the route via Liverpool Street is blocked.

There are crossovers at Fisher Street near Holborn, so a limited service could run to Bond Street from the west or Farringdon from the east.

 

[swt_passenger]

AIUI in addition to the above info from edwin m, there will also be crossovers on the surface between Stratford and the Pudding Mill portal, between Abbey Wood and the Plumstead portal, and another between Custom House and the Victoria Dock portal.

 

[Taunton]

Yes, there are a couple of crossovers in the Crossrail core (and no less than three at Custom House). But what was surprising about the Jubilee shutdown described above was what I suspect is the modern style that, despite also having a few crossovers, it not being a peak hour business day, and the main depot being at the opposite end of the line from the disruption, it was nevertheless decided that shutting the whole line end-to-end was the thing to do.

Is a problem at the Royal Oak portal/junction going to mean no Crossrail service at Canary Wharf?

 

[Bald Rick]

One of the poor design issues of Crossrail is the lack of proper reversing facilities right across the core to handle any disruption to the service. Emergency crossovers seem to be seen as optional extras nowadays, and in any event the old ability to reverse any service efficiently seems to be a lost skill, despite innumerable emergency planning meetings taking up one's diary for months ahead.

Was reminded of this only yesterday when a police incident (actually on the Marylebone line) at Willesden Green apparently led to the suspension of the Jubilee Line for the entire length through to Stratford, it being "too difficult" to arrange a short working point. It really is inappropriate for all the Jubilee's central London usefulness, and the cross-river connections in East London, to be entirely lost because of something that has happened over in Willesden, and surely the same is going to apply to Crossrail.

In a way you've answered your own question. The reversing sidings / crossovers south of Willesden Green would enable, at most, an 8-10tph service. Whilst it wasn't a normal working day, the off peak in the Jubilee is still heaving, particularly in a Bank Holiday with normal shopping hours and all the Tourist attractions in full flow. Cutting more than half the service out would inevitably lead to station congestion with people unable to board at some stations, particularly in Zone 1. These stations might have to close as a result.

Evidently those in control thought that it was better in the round to suspend the whole service and ask people to use alternative routes than to have an unplanned limited service that would likely lead to further problems. Also, it is a lot easier (and therefore quicker) to restart a service from a complete shutdown than a partial shutdown, so recovery back to full service would be quicker.

Given all the above, why would you want to spend hundreds of millions (and it is that much) to tunnel an additional crossover in the Crossrail core?

 

[Taunton]

Given all the above, why would you want to spend hundreds of millions (and it is that much) to tunnel an additional crossover in the Crossrail core?

I just wonder how systems like the Moscow Metro, very deeply tunneled, which has not been that well endowed financially in recent decades, manage to afford to install a scissors every couple of stations, even on recent extensions, which on the (notably few compared to London) occasions when the service is disrupted manages to handle reversals straightforwardly, using both platforms alternately.

In a way you've answered your own question. The reversing sidings / crossovers south of Willesden Green would enable, at most, an 8-10tph service. Whilst it wasn't a normal working day, the off peak in the Jubilee is still heaving, particularly in a Bank Holiday with normal shopping hours and all the Tourist attractions in full flow. Cutting more than half the service out would inevitably lead to station congestion with people unable to board

Sounds like Canning Town in the morning peak at present, with the PA booming out that it's a "Good Service".

But I feel it does answer my question, which is that the minimalist designs of nowadays are not fit for purpose, where a disruption out at one end affects the entire core service because inadequate provision is made for irregular operations. Which I am afraid will come along In Spades with Crossrail hiccups.