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Post by Deleted on Apr 7, 2007 7:07:39 GMT
During a handle down incident on an Ealing service departing Plaistow, the T/Op left the train stalled over the crossover west of the station while he went all the way through the train to reset the handle and find out what went wrong. During this period I happened to look at the inner home signal guarding the points into the bay platform and noticed that it was plated FC11c8b!
A quick look at the trailing crossover showed that the shunt signal protecting the main line shunt from the w/b line was plated FC8a, which I found to be very interesting - it was apparent that FC11c8b was set up to clear in tandem with FC8a to allow a main line shunt from the w/b line to either the e/b line or the bay platform.
The things I'm curious about are:
1. Why was FC11c8b positioned between the crossover and the bay points, as opposed to being positioned to the rear of the crossover?
2. Has this type of signal configuration ever been used elsewhere on LU?
3. Is this type of signal configuration harder to design, construct and test than a more 'normal' configuration such as a shunt signal w/shunt route indicator?
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Harsig
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Post by Harsig on Apr 7, 2007 11:58:22 GMT
During a handle down incident on an Ealing service departing Plaistow, the T/Op left the train stalled over the crossover west of the station while he went all the way through the train to reset the handle and find out what went wrong. During this period I happened to look at the inner home signal guarding the points into the bay platform and noticed that it was plated FC11c8b! A quick look at the trailing crossover showed that the shunt signal protecting the main line shunt from the w/b line was plated FC8a, which I found to be very interesting - it was apparent that FC11c8b was set up to clear in tandem with FC8a to allow a main line shunt from the w/b line to either the e/b line or the bay platform. The things I'm curious about are: 1. Why was FC11c8b positioned between the crossover and the bay points, as opposed to being positioned to the rear of the crossover? 2. Has this type of signal configuration ever been used elsewhere on LU? 3. Is this type of signal configuration harder to design, construct and test than a more 'normal' configuration such as a shunt signal w/shunt route indicator? 1 Headway reasons I should imagine. 2 OJ 14 E/19 B is another example. There are probably others |
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Post by Deleted on Apr 7, 2007 12:47:10 GMT
2. en43/44 is the same setup
3. same way in testing just gets a bit complicated with the lever operations circuit which is a non-safety circuit
if memory serves me right there is only one route for fc8 which is back into the e/b platform so you cannot go into the bay platform via 13rt1
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Deleted
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Post by Deleted on Apr 8, 2007 22:37:02 GMT
There are a few locations like that, where it has to be drummed into new drivers that they MUST comply with these intermediate / inner home's before reaching a platform. There is a tendancy to presume you get the shunt and thus are cleared into the platform ... rather than cleared to that next signal.
Begging to differ from aetearlscourt's memory, if accepting the shunt FC8A (from the westbound to eastbound) your next signal encountered is FC8B which is the "junction" signal carrying the route indicator (harbor lights) and that can be set for either the eastbound main or the bay in the usual way, as far as I am aware.
An example of why this may be necessary (and why I'm sure it can be done) a few weeks back a youth threw a bottle at a train cab window as it arrived at Plaistow w/b, the driver was shaken and declined to continue. In order that the service could continue, he was persuaded to detrain, proceed to the limit of shunt and then reverse back from FC8A into the bay road.
And just to confirm such loutish behaviour is not confined to the east end, last week a bottle was thrown at my cab window, and smashed upon it, from the road bridge to the south of Gunnersbury station ! However i continued in service ...occupational hazard (to quote a phrase ;D ) !!
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Oracle
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Post by Oracle on Apr 8, 2007 22:54:07 GMT
Can I just say here that this has made fascinating reading, and I have ben checking Our Illustrious Leader's track diagram to see what you have been talking about: www.trainweb.org/districtdave/Plaistow.jpgThanks for the elucidation! |
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Post by mandgc on Apr 11, 2007 10:08:47 GMT
It is rather interesting to see that Shunt Signal FC 8A leads to, and works in conjunction with, Running Signal FC 8 B. In fact it seems rather unusual that any Shunt Signal (A) should work in conjunction with another (B)signal.
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Tom
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Post by Tom on Apr 11, 2007 20:03:43 GMT
It's more common than you'd think. Another example is VN1A (Northumberland Park Depot outer home), which is a colour light when the B signal a bit further on is a fixed red and disc.
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mrfs42
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Post by mrfs42 on Apr 12, 2007 0:48:03 GMT
Just a quick thought...
Off the end of 41, 42 and 43 roads reading towards the depot at Morden, are the fixed red lights Y(6 or 7 or 8) A with the discs underneath being Y (6,7,8) B?
I know it's not quite the same situation, but this thread got me thinking. ;D
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Deleted
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Post by Deleted on Apr 12, 2007 18:38:20 GMT
No, they aren't - each shunt signal is independently plated. www.trainweb.org/tubeprune/Morden-lmo5-4.gif refers. You're actually thinking of Northfields - IMR 'WR' has at least two of these on the w/b island. The A signal is the colour light starter for the w/b road to Boston Manor, and the B signal is the shunt into Northfields Depot. I believe the relevant levers are 31 and 32, and Harsig/aetearlscourt/BAET could probably explain to us how the signals are interlocked (i.e. which one clears when the levers are rotated reverse). |
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Tom
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Post by Tom on Apr 12, 2007 21:24:20 GMT
The appropriate signal is most likely selected over point positions.
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mrfs42
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Post by mrfs42 on Apr 12, 2007 23:36:51 GMT
I know that; I was thinking of a diagram I've seen somewhere in my heap of yellow perils that refers to the FRLs as the A aspect - but couldn't remember where. I'm not, honestly. ;D The only bits of Picc hardware that interest me are the 1978 reworking of South Harrow and the 1980 resignalling of the Aldwych branch. The yellow perils are quite interesting - if you're into that sort of thing  It's just a matter of drawing up an appropriate table of controls, enumerating which pointblades/tracklocks are detected normal/reverse and in/out and drawing up a 'selection' circuit: bit like a logic table - though in the circuit design you've got to prevent relays 'chasing' each other so the whole thing doesn't tie itself up in knots. Importantly, the route must be proved to be set and locked for a route indicator to clear and that route indicator must be proved alight before the signal clear. (in this you could substitute 'appropriate signal aspect' for 'route indicator') - I may be thinking too many levels of proving here. ;D |
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