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Post by happybunny on Nov 25, 2008 15:53:29 GMT
I noticed recently, that the above signals (between Upney to Becontree eb) clear at the same time, rather than 939 first then 943a next... How long have these signals been doing this?
I presume this is not how they are supposed to work... any plans to actually repair them so they work correctly (crazy suggestion perhaps) ?
Or are they destined to go on the list of permanent District line no-hope signals, alla Ealing Common, Hammersmith etc
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Post by chrish on Nov 25, 2008 18:59:46 GMT
I noticed recently, that the above signals (between Upney to Becontree eb) clear at the same time, rather than 939 first then 943a next... How long have these signals been doing this? I presume this is not how they are supposed to work... any plans to actually repair them so they work correctly (crazy suggestion perhaps) ? Or are they destined to go on the list of permanent District line no-hope signals, alla Ealing Common, Hammersmith etc They are designed to work like that I believe. Something to do with compromised overlaps at Becontree i think. They have definitely worked like this since I started driving past them! |
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Post by Deleted on Nov 25, 2008 21:08:46 GMT
as stated above theres a few around been like it a while now
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Post by Dstock7080 on Nov 25, 2008 23:11:40 GMT
Add to those: approaching West Ham EB; between Dagenham East & Elm Park EB.
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Post by Deleted on Nov 25, 2008 23:41:34 GMT
They were not designed like it ... but were connected together becuase of a compromised overlap. A train SPADing A943a at full speed with poor D stock brakes could thoretically still collide with a train berthed in Becontree platform.
One assumes R stock and CO / CP brakes were such that this wasn't an issue.
This also applies to signals eastbound at West Ham and Elm Park.
It remains a joke, and often delays any hope of service recovery up the east end of the line.
The obvious solution is to move A 943a in rear so that it is a stopping distance from Becontree platform. One assumes this wouldn't be too complex, just cut a new IBJ (Insulated Block Joint) and move the train stop / signal and existing connections.
Everything is expensive on LUL but the present solution can't have been much cheeper but causes much delay, especially seeing as there is about a quater of a mile between A939 and A943a. The Elm Park one is even more of a pain !
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Post by Deleted on Nov 26, 2008 1:06:00 GMT
I agree with everything aspect said above, except that I suspect the distance involved is rather more than a quarter of a mile and therefore the delay is even greater.
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Colin
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My preserved fire engine!
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Post by Colin on Nov 26, 2008 12:41:28 GMT
Common sense would suggest that the signals could easily be moved when the track is replaced with flat bottom (although admittedly Elm Park east has already got flat bottom). Then again, did I just say common sense?  ;D ;D |
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Tom
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Signalfel?
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Post by Tom on Nov 26, 2008 22:20:04 GMT
They were not designed like it ... but were connected together becuase of a compromised overlap. A train SPADing A943a at full speed with poor D stock brakes could thoretically still collide with a train berthed in Becontree platform. One assumes R stock and CO / CP brakes were such that this wasn't an issue. This also applies to signals eastbound at West Ham and Elm Park. There have been compromised overlaps out there for years - some of the more recently mitigated ones have been listed as compromised since the 60s (I've got a copy of the list somewhere). It comes from the overlap formula becoming more refined (i.e. restrictive) over the years and the signals originally being deficient upon installation. West Ham EB did have a special circuit to reduce the impact, but there was a design error associated with it and thus was hurriedly decommissioned. It has never been modified to resolve the error and the line management are able to run without the circuit, so there is no rush to do anything! |
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Post by Deleted on Dec 1, 2008 21:41:04 GMT
Same thing as ealing common from the sounds of it with WM400 which is supposed to slow the train down to WM4a all because of the points ahead etc.
This hasnt worked for absolutely years so the only time it clears is when the 4A/4B signal is cleared defeating the whole idea of having a draw up signal
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Post by happybunny on Dec 1, 2008 22:06:18 GMT
so the only time it clears is when the 4A/4B signal is cleared defeating the whole idea of having a draw up signal Sometimes not even then, 3 to 5 seconds later even !! What a spad trap... but instead of fixing these kind of spad traps, its easier to send a leaflet to all the drivers telling us to "Drive with care, you're in the chair" ... and "don't be too keen, wait till its green" (new drivers who have just passed out are said to be keen and purposely go winding up against reds because they are just so excited... they can't wait for it to clear !! ) |
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;D ;D
