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Post by still not logged in on Jun 28, 2005 22:13:48 GMT
last time i was in the big smoke, i noticed a white signal aspect at, i think, oxford circus b'loo line (can't remember which direction) - anyone know what this curious shade means?? it wasnt a junction indicator either...not many of the underground I dont suppose! same weekend, indcidentally, I also had the pleasure of seeing the track recording train which appeared to actually be a mobile canteen with a couple of big UNIX boxes and a some very bored looking techies onboard...!! amusing to see people rushing to try to get on it - was almost last train time...
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Post by Christopher J on Jun 28, 2005 22:26:20 GMT
I've never heard of a White Signal Aspect on the Bakerloo at OXO. Are you sure you were on the Bakerloo and not the Central Platforms? There are white Signal Aspects on the Central as they're a part of the signalling system on the line. Taken from www.davros.org/rail/signalling/articles/central.html (see below) ---------------------------------------------------------- green line clear to next signal, all trains may pass; all block sections up to the next signal are transmitting a code other than "stop" white
a target speed other than "stop" is being transmitted, trains in Automatic or Coded Manual mode may passred stop (the target speed in the code will be "stop") |
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Deleted
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Post by Deleted on Jun 29, 2005 0:37:31 GMT
This has always bothered me about white signal aspects! What if a red signal has the lens broken (which I've seen happen several times) leaving a white light. Obviously a 'manual' driver would know that it shouldn't be a white aspect, but could the same thing happen on the Central?
Sorry, I know absolutely nothing about the Central line auto operation!
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Post by q8 on Jun 29, 2005 1:06:05 GMT
Me agin. We were always told that if you saw whiter where there should be a colour it was treated as a danger signal and dealt with accordingly.
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Colin
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Post by Colin on Jun 29, 2005 1:35:34 GMT
I know nothing about the Bakerloo line, but i'll have a go! Is this light on it's own or near other signals?
If it's on it's own, I have no idea. If it's with other signals, you are looking at a trip cock tester light. These lights are either 'Lunar' White, Blue or Purple.
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Post by q8 on Jun 29, 2005 2:25:14 GMT
Well if it was the TT then it's moved as it used to be at Piccadilly Circus and not only gave an indication to the driver but in the cabin as well
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Post by banana on Jun 29, 2005 7:29:11 GMT
This has always bothered me about white signal aspects! What if a red signal has the lens broken (which I've seen happen several times) leaving a white light. Obviously a 'manual' driver would know that it shouldn't be a white aspect, but could the same thing happen on the Central? Sorry, I know absolutely nothing about the Central line auto operation! IIRC In automatic operation the train won't pass a "red" signal even if the lens is broken. The white signal is there as an indication to the driver only (i.e. to let him close the doors at a station etc.) |
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Tom
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Post by Tom on Jun 29, 2005 9:34:25 GMT
And the ex-Bakerloo boy catches up finally....
There aren't any white aspects on the Bakerloo at Oxo, the Tripcock testers are at Baker Street and even they have purple lenses. (OK, the one on the NB is white but it should be purple).
Should a lens break on the central (or the wrong lens be fitted) the train is protected by the ATP system. It doesn't deal with drivers who go into restricted manaul, but will cover most eventualities.
My guess is the white aspect seen was on the Victoria or Central.
Normally, should a lens break it will be fairly obvious, as our signal lamps in tunnel sections are so dim they are more yellow than white, which is the reason our green lenses are actually blue.
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Post by Bakerloo Bill on Jul 1, 2005 20:37:44 GMT
mystery solved!
the white light is indeed at oxo n/b on the bakerloo, on the right hand side. however it is not a signal it is a lamp used to illuminate the 20mph speed restriction board that has been twisted from its original position so it is visible from the platform! the station starting signal is positioned inside the tunnel mouth on the left and i don't think is visible from the platform...
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Tom
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Post by Tom on Jul 2, 2005 10:03:04 GMT
Not this 20mph PSR board by any chance?  |
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Post by not logged in again on Jul 5, 2005 21:48:57 GMT
hello! thanks for that bakerloo bill!! im glad i wasn't completely seeing things....!! great pic of the tunnel....ive never ever seen a tunnel section so clearly before....would be really interesting to have a wander about below the streets one night....!!
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Deleted
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Post by Deleted on Jul 6, 2005 0:07:02 GMT
....would be really interesting to have a wander about below the streets one night....!! Make sure you tuck your trousers into your socks then! There be rats around those tunnels! ;D (By the way, you really must log in one of these days! ;D) |
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Post by Christopher J on Jul 6, 2005 20:36:30 GMT
This has always bothered me about white signal aspects! What if a red signal has the lens broken (which I've seen happen several times) leaving a white light. Obviously a 'manual' driver would know that it shouldn't be a white aspect, but could the same thing happen on the Central? Sorry, I know absolutely nothing about the Central line auto operation! Another alternative was if the stick was displaying a Clear (Green) aspect, but with a smashed lens, the T/Op should look at the 'target speed' and see what code the Train is receiving, if it’s showing the full line speed it would obviously mean the block ahead is clear. If it the stick is at danger the target speed would display 0kph. (I think) |
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Tom
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Post by Tom on Jul 6, 2005 20:47:11 GMT
ive never ever seen a tunnel section so clearly before.... It's actually a lot lighter in the photo than to the naked eye, courtesy of a tripod and a long exposure on my camera (15 sec or so IIRC). |
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Post by Bill on Jul 6, 2005 21:11:36 GMT
Bakerloo trains are manually driven. Target speeds etc is all Greek to me! I wouldnt fancy working one of the Auto lines.
It's also worth noting that for some reason all station starters on the Bakerloo are approach controlled, the stick will only come off if you have slowed the train down sufficiently. You will never see a clear station starter if there's no train in the platform.
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Tom
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Post by Tom on Jul 6, 2005 21:19:54 GMT
The approach control on starters is a precaution to ensure the train recieves a speed check in the platform. If it didn't, in theory a train which has to pass the station could do so at line speed, leading potentially to it exceeding the speed that the signal overlaps are calculated for, and if tripped would stop beyond the overlap.
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Post by Harsig on Jul 7, 2005 9:19:45 GMT
Does anyone know why they don't have this on, say, the northern line? do they trust the drivers over there more?! ;D No it is simply that it is a relatively new innovation in the signalling principles. The change presumably took place after the Northern line was last resignalled but before the Bakerloo was done. The same arrangement applies on the Uxbridge Branch of the Met line. |
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Post by nutterathome on Jul 11, 2005 19:19:31 GMT
White Signal Aspects are as common day and night, but only on the Central Line. During the transition from Tripcock to ATP some areas had the new signals in operation but not ATP Codes. These Signals show Red-White-Green. Not preaching to the coverted but this is what it means.
Red - Stop no matter what mode the train is in, Coded Manual or ATO
White - This means that you can proceed as far as ATP Codes are available but you will find a Train in the section between Colour Light - Colour Light.
Green - Off you go as far as the next Colour Light, nothing in section ahead.
It's fun when a Battery Loco fitted with ATP decides it 'aint gonna play', it still has Tripcock Mode but is it safe to run CL - CL or Signaled section to Signaled Section, I will leave you to work that one out but may reply to private e-mails.
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