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Post by earlyelectric on Apr 5, 2011 10:18:43 GMT
Hi
I've seen photos of slotted semaphore signals on inner circle platforms (western end of the circle) in the 19th century. Anyone know how long these signals stayed in use?
Jon
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mrfs42
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Post by mrfs42 on Apr 7, 2011 9:14:53 GMT
Slotted post signals became very much infra dig for the larger railway companies after the Abbots Ripton accident of 1876. The GNR in particular went towards their somersault arms (also used by the Barry Railway and in Victoria), as the slotted post was a contributory factor in the accident - although more attributable to 'normal clear' block working and time interval working.
Bear in mind too that the slotted post signals were originally three-position and that facility wasn't used after Lock and Block started to be used on the MDR or the Met. and GW to Hammersmith.
I would suggest as a first approximation that the slotted post signals were removed during the 1880s. I think there were 'ordinary' semaphores before the EP types.
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Post by Deleted on Apr 7, 2011 11:47:22 GMT
Hang about. What is meant by "slotted"?
On the one hand, there are signals that drop down into a slot in the signal post to indicate "clear". As mrfs42 says, these went out of use after Abbots Ripton.
On the other hand, when one signal box's distant was on the same post as another box's home, there was an arrangement known as "slotting" to ensure that the distant could not show "clear" when the home showed "stop".
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mrfs42
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Post by mrfs42 on Apr 7, 2011 12:11:55 GMT
Hang about. What is meant by "slotted"? Wise question - I think given the timescale of the OP we're talking about slotted post signals - from memory there were very few (in fact I can't actually think of an example [1] for sure) of the other type of 'slotting' on the Inner Circle in the 1800s. [1] Minories might have worked a couple of slots before 24/1/06, prior to the EP installation. Can't check at the mo, because I'm on my spare machine in my spare house and I've not got those notes here any more. |
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Post by norbitonflyer on Apr 7, 2011 17:32:34 GMT
Slotted post signals .......... was a contributory factor in the accident - although more attributable to 'normal clear' block working and time interval working. . I don't think time interval working was in operation - the accident was caused by "false clears" being given due to the signal being frozen into the slot (at clear) |
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Post by earlyelectric on Apr 7, 2011 19:28:48 GMT
Sorry about the inexactitude. I meant slotted post. The photo I have seen looks to be on the NW corner of the circle between West Ken and Paddington. Yellow brick arched retaining walls, curved roof with a pitched centre, and open to the sky outside the station between roads.
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mrfs42
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Post by mrfs42 on Apr 8, 2011 6:54:32 GMT
Slotted post signals .......... was a contributory factor in the accident - although more attributable to 'normal clear' block working and time interval working. . I don't think time interval working was in operation - the accident was caused by "false clears" being given due to the signal being frozen into the slot (at clear) Yes - you're quite right, having now read the accident report - that bit of the GNR was all AB even then. I wonder which accident I was thinking of then? Clayton Tunnel, perhaps? |
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