Why is Crossrail so late?

dutchguylivingintheuk

Senior Member
Most modern projects are late, that it becasue they all use simulations and those kind of fancy stuff and that looks all cool and nice on paper, but for example when they where building an underground line in Amsterdam a few years back, they found out the hard way that their calculations did not account for the soft clay/mud ground.
So they had to emergency evacuate people because there houses where sinking into the ground.
Now i don't know what kind of ground there need to drill trough for the crossrail but i guess it are similar issues that are not seen on the screen but are a thing in real life.
 
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Yellow Fang

Yellow Fang

Legendary Member
Location
Reading
As I understand it, AWS, ATP and TPWS are all fixed block, whereas ETCS is moving block, so rather different.
Maybe I've found a reason to blame Sadiq Kahn. ETCS is quite a new system. Elements of it were not very well understood. But it is European, so Sadiq Kahn is unlikely to suggest it be dumped.
 

Darius_Jedburgh

Looking for the lost chord.
What's so special about Crossrail? Oh yes. It's for Londoners. So that makes it special.
How much has it cost? How much is it over budget? Non of that matters. It's for Londoners.
Up here we've been fighting for years to get a disused junction reopened. This would make a vast difference. How much is needed? £750,000. Guess what? There's no money. Why? Because it's all been spent on Crossraill. And that is official. Straight from Dept for Transport.
But it's for Londoners so that makes it alright.
Why are we spending vast sums on HS2? It's for Londoners. so that they can live where houses are cheaper but still get into the office.
Rail improvements north of Birmingham? Forget it. There's no money. It's all been spent on Londoners.
 

Bromptonaut

Rohan Man
Location
Bugbrooke UK
Maybe I've found a reason to blame Sadiq Kahn. ETCS is quite a new system. Elements of it were not very well understood. But it is European, so Sadiq Kahn is unlikely to suggest it be dumped.
It was specified that way long before Khan was Mayor.

What, based on your experience, could replace it and achieve the required 24 tph service pattern.
 
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Yellow Fang

Yellow Fang

Legendary Member
Location
Reading
It was specified that way long before Khan was Mayor.

What, based on your experience, could replace it and achieve the required 24 tph service pattern.
Dunno. Is ETCS used on the other underground lines? I know ETCS is used on the Heathrow train and some new SWR trains. The Heathrow train goes underground for some of its journey. GWR have the ETCS system on some of their high speed trains, but I don't think they use it.

I am a bit surprised Crossrail plan 24 journeys an hour across London. Presumably these aren't all from Reading to Abbey Wood. I can't see how they could do this while sharing track with other rail companies.

ETCS seems a bit complicated to me, but no doubt the drivers would get used to it.
 
Though I share a little bit more about signalling after the Jubilee Line came into being. Signalling is no longer what we layperson thinks it is. It the system that allows trains to run back to back in very close formation with no human interference. As one departs the next is already arriving. If a train door cant's close because someone's big luggage bag is caught, the entire line compensates without we realising it. Even in our present underground, if staff sees someone struggling with too many bags on CCTV, staff with a flag is assigned to assist the passenger so no delay occurs.

Crossrail original target I am told is 30 trains per hours. I think it has been dropped to 20 for now. They are already have the ETCS to run 30 but they have switched it off and using existing because part of it is on existing track work. I am told it is the most important and last phase before it goes operational fully. It is essentially an anti-collision system.

Crossrail is also more complex in line and station construction. Just have to look at Canary Wharf Crossrail station. It is one of the biggest infrastructure project. It was passed in Parliament with bipartisan support.
 
Location
London
The Overground is, for the most part, a linking of long standing lines.
yep - mostly it's rebranding - the proportion that is newbuild must be tiny I'd imagine - I know they did a crossover thingy near New Cross. I remember when bits of it were the positively spooky East London line - a university mate of mine hardly believed it existed - and still wasn't sure after we were the only folks to get off at wapping and emerge into a deserted street after passing the ticket collector in his box with his kettle.
 

BrumJim

Forum Stalwart (won't take the hint and leave...)
24 trains per hour, really?

"Crossrail trains will share tracks with Great Western Railway and Heathrow Express services out of Paddington to Reading and Heathrow, and with Great Eastern services from Liverpool Street to Shenfield."
What, I thought they were building additional tracks.

"So, as well as CBTC, Crossrail trains have to be fitted with ETCS, TPWS and AWS, with automatic changeover between the systems at the appropriate point."

Actually, I know a bit about this, because I maintain train simulators, but I am not so much bothered about which buttons you should press when, but whether the component works at all. ETCS is the European system, boo, hiss. The ATP system, is an older system dating back several decades. The AWS system is even older. It goes 'ping' when the train over over a magnetic block in the tracks, but only if the next signal is green. If the signal is not green it makes a loud noise and a sunflower lamp comes on. I am not sure how the TPWS system works. I know if you jump a red the train comes to a stop and a message sounds in the cab to call the signaller, in which case you had better start worrying about your mortgage. My company provided the simulators for Crossrail several years ago, but they are not ones I maintain. I suppose it would be better to read the manuals for this stuff when travelling to Plymouth, rather than reading the great works of literature, but as far as I am concerned, it's software.
ATP was the old BR system that is now defunct, and being replaced by ETCS.

TPWS works from two grids, and therefore the on-board equipment can determine if the train is running too fast for the next signal, if it is caution (yellow(s) or red). If it is too fast, the brakes will come on. I think TPWS is probably the greatest benefit to train safety since the introduction of AWS. OK, ETCS gives you train speed control for 100% of the time, but that only adds safety benefits when the driver is likely to accelerate after a caution signal.
 

BrumJim

Forum Stalwart (won't take the hint and leave...)
As I understand it, AWS, ATP and TPWS are all fixed block, whereas ETCS is moving block, so rather different.
ETCS can be many flavours. Level 1 is fixed block, level 2 is fixed block with track to train telemetry. Only level 3 is moving block, and I'm not sure that anyone has managed to put level 3 into service anywhere yet.

CBTC is a bit tricky, particularly if you are overlaying it with another signalling system. Turkey had a lot of problems with it in the Marmaray tunnel with long delays.
 
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Yellow Fang

Yellow Fang

Legendary Member
Location
Reading
I read Thameslink did it with ETCS overlaid with ATO (automatic train override). Crossrail looked at it, but did not think they could achieve their journey targets with it. In the early days the authorities decided they wanted something better than TPWS.

I know writing quality software is very difficult. I wonder why it is necessary to have software to convert one system to another. Can't they just run the three systems in parallel?

I wonder what the drivers make of ETCS. From my limited experience it is like having a back seat driver. It pretty much knows what the driver should be doing so why not just do it itself? It is also not very intuitive.

It's strange with modern trains. You need a degree to learn what all the kit does, but then you hardly have to be there. Pretty much like flying planes I expect.
 
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Yellow Fang

Yellow Fang

Legendary Member
Location
Reading
I was talking to someone at work about it. I have to admit I did not follow everything he said. He thought Crossrail was a lot of money to save ten minutes on your commute. He said they could fit more trains on the line using ETCS because the trains required less 'head space', which is the space between one train and the next. If I understood right, you have internal signalling with ETCS. You can see the signals moving towards you on a screen rather than looking out the windscreen. I suppose it is similar to the principle in driving that you should not drive so fast that you cannot stop in the space ahead you can see to be clear. If you know what's ahead, you can squeeze a bit tighter. He says there is a massive great computer room some place where this ETCS signalling is all governed. He did say it was a future proof system but might not be implemented on every line before we retire. He also said there was some test line in Wales where the signals go from old fashioned semaphore to ETCS. Crossrail sounds like a typical MOD procurement project to me.
 

BrumJim

Forum Stalwart (won't take the hint and leave...)
I was talking to someone at work about it. I have to admit I did not follow everything he said. He thought Crossrail was a lot of money to save ten minutes on your commute. He said they could fit more trains on the line using ETCS because the trains required less 'head space', which is the space between one train and the next. If I understood right, you have internal signalling with ETCS. You can see the signals moving towards you on a screen rather than looking out the windscreen. I suppose it is similar to the principle in driving that you should not drive so fast that you cannot stop in the space ahead you can see to be clear. If you know what's ahead, you can squeeze a bit tighter. He says there is a massive great computer room some place where this ETCS signalling is all governed. He did say it was a future proof system but might not be implemented on every line before we retire. He also said there was some test line in Wales where the signals go from old fashioned semaphore to ETCS. Crossrail sounds like a typical MOD procurement project to me.
Hmm - a lot more complex than that.

Level 1 ETCS is pretty much the same as we have at the moment, only less space efficient. Don't really know much about this, only that it is compatible with other levels of ETCS, so may be implemented some time in the future on lightly used branch lines when the old equipment is life-expired. It is very similar to classic signalling.
Classic signalling (e.g. AWS in the UK) relies on fixed blocks. A train isn't allowed into a block until the train before it has left the block. Multi-aspect signalling involves warnings so that the driver reduces the speed if the next but one (or two) blocks are occupied. In all cases, though, the train driver doesn't have a clue as to what the train in the next block is doing. It could be stationary (in which case you definitely need to slow down) or going at line speed, in which case speed reduction is unnecessary.
Level 2 ETCS involves radio communications, so that you know what the train in the next block or two is doing, and so can drive faster / closer without the risk of crashing into it. Still fixed block, though, so the train could be right at the start or right at the end of it, so the safety gap could be much bigger than necessary.
Level 3 ETCS is moving block, so it is pretty clear where the next train is, and trains can therefore run a lot closer together.

For clarity, ETCS is the bit currently being implemented on the line from Hayes to Heathrow, and which will eventually be implemented on everything West of Paddington to take over from ATP. All this is above ground.
CBTC is being implemented in the tunnel. ETCS needs radio links which can't be established in a tunnel, so CBTC is used again. This is similar to ETCS, but with a bit more experience of moving block signalling, as very tight headways are desired where the infrastructure cost of tunneling (sometimes undersea tunneling) is necessarily high. i.e. it will cost you a lot of money to build a big tunnel, so only really worth it if you run lots and lots of trains down it.
 
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