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Post by jamesm on Jul 23, 2007 18:16:38 GMT
On London Transport lines, at what stage after a train has passed a repeater signal at green does the aspect change to yellow?
James
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Post by Deleted on Jul 23, 2007 19:06:19 GMT
I believe the repeater turns yellow as soon as the train has passed, even if the train has not yet passed the signal it is repeating.
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Post by Deleted on Jul 23, 2007 19:39:03 GMT
That is correct as far as my understanding goes - each repeater , including fog repeaters each have their own block joint.
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mrfs42
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Post by mrfs42 on Jul 24, 2007 0:23:19 GMT
That is correct as far as my understanding goes - each repeater , including fog repeaters each have their own block joint. I thought Fog Repeaters and repeaters were parallelled up. [1] Might be wrong though - am thinking of a sequence with at least 2 auto sticks with FRs underneath both. [1] there may be a back contact off the berth track circuit [2] of the auto that acts as a 'global' replace for that particular signal post[2] or am I thinking of the difference between outside fed and inside fed TQs? Certainly a block joint for every individual aspect [3] would be rather cable-heavy. [3] I'm thinking of green over green over green. (non-supressed) |
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Post by Deleted on Jul 24, 2007 3:25:43 GMT
I'm not so sure about this - I think I've seen standalone repeaters stay green until the linked stop signal turns red; repeaters that drop to caution after passing them are more of an NR thing, aren't they?
Subsidiary repeaters, though, are a different story - mrfs42 can probably post lots of circuit descriptions on how a subsidiary repeater is extinguished as part of the stop signal returning to red.
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Post by Harsig on Jul 24, 2007 9:03:08 GMT
I'm not so sure about this - I think I've seen standalone repeaters stay green until the linked stop signal turns red; repeaters that drop to caution after passing them are more of an NR thing, aren't they? I would have said the exact opposite, the only exceptions as far as I am aware being platform repeaters. These of course remain green while the station starter is green for the information of staff other than the driver i.e. platform staff and guards (when we had them) |
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Post by Deleted on Jul 24, 2007 9:30:33 GMT
as soon as the train goes past the blockjoint on the next track the repeater will go back to amber this drops the PGR (P= Repeating G = Signal R= Relay) and the amber is fed from a back / down contact and the green is fed from a front / up contact
platform repeaters just copy the station starter as it is fed from the same relay (GR G= Signal R= Relay)
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Post by Deleted on Jul 24, 2007 12:28:49 GMT
Ah - now it makes sense; I was probably thinking of a platform repeater, then.
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Tom
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Post by Tom on Jul 24, 2007 13:41:56 GMT
That is correct as far as my understanding goes - each repeater , including fog repeaters each have their own block joint. I thought Fog Repeaters and repeaters were parallelled up. [1] Might be wrong though - am thinking of a sequence with at least 2 auto sticks with FRs underneath both. [1] there may be a back contact off the berth track circuit [2] of the auto that acts as a 'global' replace for that particular signal post[2] or am I thinking of the difference between outside fed and inside fed TQs? I think you might be thinking about the Red Light Circuit, which is often used for things like repeater control and lighting. |
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mrfs42
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Post by mrfs42 on Jul 24, 2007 18:24:03 GMT
I think you might be thinking about the Red Light Circuit, which is often used for things like repeater control and lighting. I think I was too; looking at what I actually wrote. A description of one of the circuits I was thinking of (at that time) for TOK: 2GVCR (R1) to arm of 2GR 8: back contact of 2GR 8 to 2V "ON" (1.1, 1; 2.2, 2 - paralleled up) then 2V "ON" 5 , 5.5: 5.5 to arm of 2GR 7 5 to back contact of 2GR 8 - BX100 feed. 2GVCR (R2) to N/NX100 terminal to 2RE to arm 2GR 7Which isn't quite what we're discussing here, though. I think I deserve an award for impenetrability for this posting! ;D |
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Tom
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Post by Tom on Jul 24, 2007 20:42:53 GMT
It sounds very like a combined RE/GVCR circuit, but not quite how I would expect it.
Try this:
BX100 to 2GR7B. 2GR 7B to 2V 'On' 5, looped to 2 and 1.
2V 'On' 5.5 to 2GR7A to 2RE thence to NX100.
2V 'On' 2.2 looped to 1.1, 1.1 to 2GR 8B, 2GR8A to 2GVCR R1, 2GVCR R2 to NX100.
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Post by Deleted on Jul 24, 2007 21:06:20 GMT
 ;D |
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Post by Deleted on Jul 24, 2007 21:23:32 GMT
I'm glad I'm not the only one who is now totally confused!
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Tom
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Post by Tom on Jul 24, 2007 22:30:11 GMT
It makes more sense on a drawing (but only just!).
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mrfs42
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Post by mrfs42 on Jul 25, 2007 0:37:38 GMT
It sounds very like a combined RE/GVCR circuit, but not quite how I would expect it. It was. RE/GVCR circuitry (if you can believe what I type) shows the ingenuity of Dell and the guaranteed [1] RE. Try this: BX100 to 2GR 7B. 2GR 7B to 2V 'On' 5, looped to 2 and 1. 2V 'On' 5.5 to 2GR 7A to 2RE thence to NX100. 2V 'On' 2.2 looped to 1.1, 1.1 to 2GR 8B, 2GR 8A to 2GVCR R1, 2GVCR R2 to NX100. Same circuit, different way of expressing it - I think. You've swapped arms  I was quoting from memories of the circuits for ZZ2. A lot of people over the years have tried to understand how 'ZZ' works. note to TOK, IMR/SER 'ZZ' really does exist. ;D ;D [1] for certain values of 'guaranteed' |
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Post by mandgc on Jul 25, 2007 1:26:55 GMT
I would have thought that the principle of any Signal going to its most restrictive aspect as soon as practicable- even at the 'added' expence of installing an additional Block Joint or other equipment- was essential. Situations such as Curves,etc., No Tail Lights or Smoke or dust could restrict the following driver's view of the train ahead and a Yellow aspect in these cases could only help.
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Tom
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Post by Tom on Jul 25, 2007 21:58:46 GMT
Same circuit, different way of expressing it - I think. You've swapped arms I don't think you had any wires on 2GR 7B |
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mrfs42
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Post by mrfs42 on Jul 25, 2007 22:50:01 GMT
Same circuit, different way of expressing it - I think. You've swapped arms I don't think you had any wires on 2GR 7B My mind did this morning when I was rather exuberantly drunk! |
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