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Post by q8 on Apr 7, 2005 18:43:46 GMT
Somebody's asked me a question to which I don't have the answer so may you guys have one
The question is:- Where else on the combine can you see a set of "centering" points like those st Earls Court reversing road?
Anyone?
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solidbond
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'Give me 118 reasons for an Audible Warning on a C Stock'
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Post by solidbond on Apr 7, 2005 18:53:53 GMT
Well, as of a few months ago, 51RD at Upminster, where they form the new link to NR lines  . Apparently they are caller 'wide to gauge' points. |
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Deleted
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Post by Deleted on Apr 7, 2005 19:29:16 GMT
Rayners Lane, Willesden Green, West Hampstead...
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Tom
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Signalfel?
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Post by Tom on Apr 7, 2005 20:29:25 GMT
Harrow on the Hill, King's X (Vic), White City...
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Deleted
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Post by Deleted on Apr 7, 2005 21:48:41 GMT
Harrow on the Hill, King's X (Vic), White City... Wood Green, Down Street, Marble Arch... |
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Deleted
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Post by Deleted on Apr 7, 2005 22:03:12 GMT
Wood Green, Down Street, Marble Arch... You sure about Marble Arch? Last I checked it has a short unelectrified derailer beyond the trailing points for the facing crossover from the w/b main. |
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Deleted
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Post by Deleted on Apr 8, 2005 1:18:56 GMT
Wembley Park reversing siding.
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Post by igelkotten on Apr 8, 2005 11:55:35 GMT
Does somebody have a picture, or a link to a picture, of such a set of "centering" points? I want to know what you are talking about! |
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Deleted
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Post by Deleted on Apr 8, 2005 12:50:48 GMT
No pics, but I can give a potted description:
In a normal set of points, the switch rails are anchored together with a set of stretcher bars. One bar is usually provided at the sharp end of the switch rails, with another a few inches away for redundancy. These stretcher bars hold the switch rails apart in the proper position and ensure that the point drive opens one blade and closes the other when the points are moved.
The points under discussion here are properly termed 'wide-to-gauge' points. These beasts lack the stretcher bars and instead have independent drives for each blade. This means that instead of two states, 'normal' and 'reversed', you instead have three states: 'left', 'right', and 'center'. The last one opens both blades, and any train attempting to cross the points will fall off of the stock rails and onto the floor, thus derailing the train in line with the track.
In the case of Rayners Lane, wide-to-gauge points are used to prevent a train in the siding from SPADding the exit dolly and derailing near the through lines; because there is no stub beyond the wide-to-gauge points for a sand drag, the points are thus fully opened when the siding is occupied, preventing a derailed train from disturbing through services.
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Post by igelkotten on Apr 8, 2005 13:35:36 GMT
Aha! It's one of those contraptions. Now I know what you are talking about!  IIRC, they are used here and there on the mainlines in Sweden, too, although not as catch points, but as part of a compact point arrangement in places where space is at a premium. |
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Post by setttt on Apr 8, 2005 15:12:57 GMT
Does somebody have a picture, or a link to a picture, of such a set of "centering" points? I want to know what you are talking about! The ones in the foreground on the DVD cover are centering points... |
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Deleted
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Post by Deleted on Apr 8, 2005 15:45:35 GMT
newbury park is also another one
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Post by Dmitri on Apr 8, 2005 19:59:00 GMT
Symmetric points... rare beasts here... |
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