Ben
fotopic... whats that?
Posts: 4,282 
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Post by Ben on Feb 5, 2009 4:16:07 GMT
Jim, I'm not gonna dissagree with a driver  I was only going on a diagram I saw in a book about the reconstruction! |
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Post by bassmike on Feb 5, 2009 12:22:40 GMT
re st mary,s curve, as I understand it from previous posts, the blocking-off is only wooden hoarding which was previously in place during the 1990,s refurbishment of E L R.
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Colin
Advisor
My preserved fire engine!
Posts: 11,310
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Post by Colin on Feb 5, 2009 18:20:10 GMT
Looks like metal to me, but then it's hard to tell in the dark....also, the points are gone and the track has been 'plain lined'.
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Chris M
Global Moderator
Forum Quizmaster
Always happy to receive quiz ideas and pictures by email or PM
Posts: 19,410
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Post by Chris M on Feb 5, 2009 19:18:02 GMT
For all that it is the most flexible, the Central is currently suspended between White City and Leytonstone due to a signal failure at Liverpool Street. Is there no way to provide service on at least some of the central London section?
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Post by astock5000 on Feb 5, 2009 19:55:32 GMT
thelondontube.org.uk/trackmaps/#CentI've looked at this track map, and it shows there is a crossover between Lancaster Gate and Queensway, but trains can only be reversed west to east at Marble Arch and Holborn. There is also a crossover at Bethnal Green.
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Deleted
Deleted Member
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Post by Deleted on Feb 5, 2009 20:08:09 GMT
Though the Queensway cross over is in postion, it was decommisioned for sometime. It is the one move I haven't completed on the line. The move going West to East is a colour light move that can be completed with passengers, though the east to west is a shunt manover, to a fixed red. As far as I'm aware Wood Lane Control are resistant because the points can be tempremental.
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Tom
Administrator
Signalfel?
Posts: 4,100
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Post by Tom on Feb 5, 2009 21:04:59 GMT
There were two issues at Queensway which caused problems. Firstly, the track quality was quite poor and it was not unheard of for the point detection to be lost as a train ran over the crossover. Secondly there were 'code ripple' issues whereby if the codes stepped up too quickly, they caused tracks to bob as the track circuit reciever units recieved an input modulation change within one or two processor cycles, which they didin't like.
All this was sorted out by summer 2005, when a new problem was found relating to the code timing out for a train crossing over E-W if it went to slowly in Coded Manual. This was resolved by removing a parallell path ffrom the timer circuit which controlled the code.
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Deleted
Deleted Member
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Post by Deleted on Feb 6, 2009 16:37:08 GMT
Queensway crossover seems to have always been a mistake. In the 62 stock days it was removed because the track curvature caused damage to trains. It was rebuilt under The Central Line Project and now seems to be again abandoned.
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Post by superteacher on Feb 6, 2009 17:15:19 GMT
In the 1962 stock days, Queensway had a siding at the east end of the station. For the reason Jim mentioned, the siding was decomissioned in the 1980's. The crossover was built in the 1990's, and became available once the line was resignalled.
astock5000, trains can be reversed east to west at Marble Arch and Holborn. Read my first post in the thread, which explains all the moves that are possible on the line.
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Post by astock5000 on Feb 6, 2009 17:31:19 GMT
trains can be reversed east to west at Marble Arch and Holborn. But how quickly can you reverse trains there? Maybe they didn't do this because they couldn't run enough trains to Marble Arch or Holborn without there being delays, as trains have to reverse three times to do this. |
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Post by superteacher on Feb 7, 2009 2:45:10 GMT
trains can be reversed east to west at Marble Arch and Holborn. But how quickly can you reverse trains there? Maybe they didn't do this because they couldn't run enough trains to Marble Arch or Holborn without there being delays, as trains have to reverse three times to do this. It does take a bit of time. It depends on how many trains are actually running. They sometimes initially suspend services over a wide area (i.e. Leytonstone to White City) while they get to grips with the situtation. Once the backlog of trains clears a bit, the service suspension area is often reduced (in this case, possibly Holborn to Bethnal Green). They would then run something like Hainault - Bethnal Green, Epping - Leytonstone, Ealing to Holborn and West Ruislip to White City; all self contained shuttle services). |
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Post by DrOne on Feb 7, 2009 17:05:11 GMT
North of Wood Green would be a logical place as that's basically where the passenger numbers start to drop. A short extension to Palmers Green with one remaining stop could be useful. Edmonton Grn would be very useful. Either stop there or continue north and emerge just north of the branch to Enfield Town to take over the track and 3 platforms there. Ideally it would have a North Acton/Leytonstone type layout somewhere to ease convergence from the branches. Can't see it happening before extensions south of the river though. |
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North End
Beneath Newington Causeway
Posts: 1,769
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Post by North End on Feb 7, 2009 22:23:03 GMT
North of Wood Green would be a logical place as that's basically where the passenger numbers start to drop. A short extension to Palmers Green with one remaining stop could be useful. Edmonton Grn would be very useful. Either stop there or continue north and emerge just north of the branch to Enfield Town to take over the track and 3 platforms there. Ideally it would have a North Acton/Leytonstone type layout somewhere to ease convergence from the branches. Can't see it happening before extensions south of the river though. The inevitable problem would be that you end up with a Mill Hill East type problem - when the service is disrupted the Controller will have to worry about providing something of a service to the branch. Not conducive to maintaining a good service throughout the line, and a potential disaster for the branch. |
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North End
Beneath Newington Causeway
Posts: 1,769
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Post by North End on Feb 7, 2009 22:26:52 GMT
trains can be reversed east to west at Marble Arch and Holborn. But how quickly can you reverse trains there? Maybe they didn't do this because they couldn't run enough trains to Marble Arch or Holborn without there being delays, as trains have to reverse three times to do this. You can reverse fairly quickly at Marble Arch if the train has a driver at each end. But at Holborn the limiting factor is the distance between Holborn station and the siding at British Museum. There's also overcrowding considerations to bear in mind if terminating at Holborn. |
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Post by astock5000 on Feb 7, 2009 22:34:28 GMT
Can trains reverse at Holborn quicker if they terminate at Tottenham Court Road?
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North End
Beneath Newington Causeway
Posts: 1,769
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Post by North End on Feb 7, 2009 22:41:18 GMT
Can trains reverse at Holborn quicker if they terminate at Tottenham Court Road? Negative. The signalling requires trains to proceed all the way to Holborn. Under the old signalling trains would run up to the starter signal at British Museum then shunt into the siding - there was no facility to run in to the siding from Holborn e/b. The Tottenham Court Road destination on 92 stock is a legacy from the days when the trains ran under the old signalling, nowadays you would never see this destination unless Holborn station was closed. Likewise nowadays w/b trains are signalled in to the siding from Holborn platform. However under the old arrangements, I believe trains could draw up to the advanced starter if the siding was occupied. |
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Post by DrOne on Feb 9, 2009 23:37:24 GMT
Edmonton Grn would be very useful. Either stop there or continue north and emerge just north of the branch to Enfield Town to take over the track and 3 platforms there. Ideally it would have a North Acton/Leytonstone type layout somewhere to ease convergence from the branches. Can't see it happening before extensions south of the river though. The inevitable problem would be that you end up with a Mill Hill East type problem - when the service is disrupted the Controller will have to worry about providing something of a service to the branch. Not conducive to maintaining a good service throughout the line, and a potential disaster for the branch. MHE is a third branch on a very complex line so I can only imagine you are comparing this with the Picc's interface with the District and Met. Could you explain a bit more how (given the line's current difficulties) a second terminus at the north end would have a negative effect on the Piccadilly? Wouldn't a better comparison be with the Central line with 2 branches at each end of a single central section running to a simple pattern? |
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Deleted
Deleted Member
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Post by Deleted on Feb 10, 2009 14:13:21 GMT
I would have thought a branch off the Picc to Edmonton and/or Enfield would be useful from an operational point of view, as it is now any problems in the Arnos Grove area and the whole line suffers.
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I was only going on a diagram I saw in a book about the reconstruction!
