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Post by Deleted on Nov 10, 2006 21:43:47 GMT
While travelling along the H&C through Aldgate East a while back I noticed what appeared to be an abandoned buffer stop next to the e/b line next to the flat junction at the west of the station. When the changes to the layout were made in the 30s, were trap points provided on the e/b H&C line to provide flank protection?
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Post by JR 15secs on Nov 11, 2006 18:53:32 GMT
Collision protection?
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Post by Harsig on Nov 12, 2006 17:24:09 GMT
While travelling along the H&C through Aldgate East a while back I noticed what appeared to be an abandoned buffer stop next to the e/b line next to the flat junction at the west of the station. When the changes to the layout were made in the 30s, were trap points provided on the e/b H&C line to provide flank protection? shows the 1946 signalling arangements in the Aldgate area |
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Post by Deleted on Nov 12, 2006 22:44:16 GMT
Thanks Harsig  Why would half of 41 crossover be removed then? Presumably the flank protection provided by 41 crossover allowed H&Cs to clear Aldgate Junction faster, thus preventing delay for a following Met or Circle service. Now, the overlap for the e/b home signal must be so short that H&C trains have to approach said signal a lot more slowly. Was this crossover removed when the new IMR 'OB' at Aldgate was put in the mid-1990s? |
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Post by Deleted on Nov 13, 2006 15:55:32 GMT
harsig wasnt en14 en41? and it being a shunt move back into the platforms? can remember them taking it out a few years ago? i know your diagram was 1946 but whitechapel hasnt changed that much
also the points on the st marys junction are 28 on the eastbound and 29 on the westbound or were those different too
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Post by Harsig on Nov 13, 2006 17:19:51 GMT
harsig wasnt en14 en41? and it being a shunt move back into the platforms? can remember them taking it out a few years ago? i know your diagram was 1946 but whitechapel hasnt changed that much also the points on the st marys junction are 28 on the eastbound and 29 on the westbound or were those different too Whitechapel was completely resignalled in 1951, receiving a new lever frame at the same time. It is reasonable to assume that there were a considerable number of changes to the numbers of points and signals at this time. |
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Post by Deleted on Nov 13, 2006 17:48:19 GMT
harsig wasnt en14 en41? and it being a shunt move back into the platforms? can remember them taking it out a few years ago? i know your diagram was 1946 but whitechapel hasnt changed that much also the points on the st marys junction are 28 on the eastbound and 29 on the westbound or were those different too Whitechapel was completely resignalled in 1951, receiving a new lever frame at the same time. It is reasonable to assume that there were a considerable number of changes to the numbers of points and signals at this time. The booklet on Robert Dell's contributions to LT signalling has a picture of the new Westinghouse K-style lever frame sitting on rollers behind the old B-style frame, and states that after the B-style frame was disconnected and removed, the K-style frame was simply rolled into its place and connected to the signalling. |
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Post by Harsig on Nov 13, 2006 20:05:59 GMT
Whitechapel was completely resignalled in 1951, receiving a new lever frame at the same time. It is reasonable to assume that there were a considerable number of changes to the numbers of points and signals at this time. The booklet on Robert Dell's contributions to LT signalling has a picture of the new Westinghouse K-style lever frame sitting on rollers behind the old B-style frame, and states that after the B-style frame was disconnected and removed, the K-style frame was simply rolled into its place and connected to the signalling. Very true except it was an N style frame not K style |
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Post by Deleted on Nov 13, 2006 20:38:06 GMT
The booklet on Robert Dell's contributions to LT signalling has a picture of the new Westinghouse K-style lever frame sitting on rollers behind the old B-style frame, and states that after the B-style frame was disconnected and removed, the K-style frame was simply rolled into its place and connected to the signalling. Very true except it was an N style frame not K style Ah. I don't have the book to hand, so I was going by my memory which is obviously quite faulty. |
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Post by JR 15secs on Nov 14, 2006 7:23:04 GMT
LUs definition of flank protection.
The use of running signals and points to prevent a train from entering a shared route from one entry point whilst another train is traversing the route from a different entry point. Some other classic locations are Upminster and Watford South Junction.
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Post by mandgc on Nov 17, 2006 4:53:24 GMT
Flank Protection, Watford South Junction. (Reply#9)
Which points do you mean at WSJ ?
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Post by Deleted on Nov 17, 2006 10:30:35 GMT
At Watford South Junction, when a train diverges towards Watford, the points at the convergence of the fast and slow lines might have to be normal so that a s/b train SPADding the North Junction home signal doesn't hit a n/b train. By ensring that they are normal, a train SPADing said signal would instead be harmlessly diverted onto the fast lines and away from the diverging train.
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Post by mandgc on Nov 17, 2006 23:48:58 GMT
Flank Protection.
I agree with your examples at WSJ as protecting a conflicting movement in the event of a SPAD.
Iwas thinking more (probably too narrowly) of 'flank protection' being the provision of a special length of track and an additional pair of points solely for protection. The requirement that various points ( that are already part of the layout) be in Normal or Reverse positions in order to avoid conflicting situations I consider to be one of the Principals of Interlocking.
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Post by JR 15secs on Nov 18, 2006 18:44:48 GMT
The points at WSJ are 56 & 53 when these are in their normal positions 56 are for the SBM and 53 are for the NBL (N to Watford). Yes spads are a problem and seem to be increasing at some locations, but mitagation for these takes the form of 1)increasing the overlaps. 2) repostioning of signal. 3) additional signal (this was done at Gloucester Rd WB). |
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Post by mandgc on Nov 19, 2006 5:06:16 GMT
The separate Point numbers (56 and 57) for the Southbound Main connection to the Local line would seem to indicate that the overlap for Signal JJ71, when 53 and 54 points are reversed, would only extend a short distance and would allow Signal JJ 63 (with points 57 Reversed) to be lowered for a train off the Watford Line.
Is this so ?
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Post by Harsig on Nov 19, 2006 9:40:41 GMT
The separate Point numbers (56 and 57) for the Southbound Main connection to the Local line would seem to indicate that the overlap for Signal JJ71, when 53 and 54 points are reversed, would only extend a short distance and would allow Signal JJ 63 (with points 57 Reversed) to be lowered for a train off the Watford Line. Is this so ? Checking my detailed diagrams I find the overlaps provided at signal JJ71 are 1 (with 69 points reversed) 2476 feet 2 (with 56 points reversed) 1320 feet which takes us to a point midway between 56 & 53 points 3 (with 69 & 56 normal) 1364 feet to a point just byeond 54MA So the answer appears to be yes, a train can approach JJ71 while a train is signalled from the Watford Line and 56 points are reversed |
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Post by mandgc on Nov 21, 2006 23:11:24 GMT
Overlaps, Watford South Junction.
Thank you, Harsig. Now I remember -the distance between the two ends of the 'Double Line Crossover' is quite a distance unlike the other Double Line Crossover at Harrow North Junction.
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Post by Harsig on Nov 22, 2006 10:05:33 GMT
Overlaps, Watford South Junction. Thank you, Harsig. Now I remember -the distance between the two ends of the 'Double Line Crossover' is quite a distance unlike the other Double Line Crossover at Harrow North Junction. That is indeed currently the case, However I understand there are plans to relocate this part of the junction somewhat closer to Moor Park, so things are about to change. |
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Post by mandgc on Nov 22, 2006 22:44:20 GMT
So - we'll soon have another discussion on overlaps ! :-)
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