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WM400
Sept 22, 2007 19:46:50 GMT
Post by tubeprune on Sept 22, 2007 19:46:50 GMT
Thanks for that Tom.
I do know that there were places where the same was done using conventional track circuits only - no deltas. Don't ask me to quote them though.
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Deleted
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WM400
Sept 22, 2007 19:55:57 GMT
Post by Deleted on Sept 22, 2007 19:55:57 GMT
i can name one place and its whitechapel on diagrams its shows the delta symbol but physically they just normal track circuits (very short)
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WM400
Sept 22, 2007 20:38:37 GMT
Post by District Dave on Sept 22, 2007 20:38:37 GMT
Thanks for that Tom. I do know that there were places where the same was done using conventional track circuits only - no deltas. Don't ask me to quote them though. And I always thought you knew all TP  |
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Tom
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WM400
Sept 22, 2007 21:15:19 GMT
Post by Tom on Sept 22, 2007 21:15:19 GMT
Where the inductors have been replaced (as opposed to being decommissioned) proper 'two shot' timing sections have been installed, replacing the old Delta with JR circuits. OK Tom, why use a "two shot" timing section when one will do? Surely the one meets the full speed overlap requirements or do you need two for a high speed approach? Also, what's a JR circuit as opposed to a delta loop? Basically, what Harsig said. The idea is that if the train speed is too high initially but then subsequently reduces you can still get the signal to clear.This existing principle has been retained, but instead of the using the inductor as the first shot and the delta as the second shot, we just use a PD operated two shot timing section. |
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Tom
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WM400
Sept 22, 2007 21:22:02 GMT
Post by Tom on Sept 22, 2007 21:22:02 GMT
its because the relay hooked up to the inductor will only work between 15 and 20 mph as there is not enough current draw through the inductor if below 15mph I thought it was due to the FR only picking up if the input was of a specific frequency band? |
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Oracle
In memoriam
RIP 2012
Writing is such sweet sorrow: like heck it is!
Posts: 3,234
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WM400
Sept 22, 2007 22:02:57 GMT
Post by Oracle on Sept 22, 2007 22:02:57 GMT
And I always thought you knew all TP  Oracle has known TP for about 30 years now and concurs! |
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Deleted
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WM400
Sept 23, 2007 1:30:24 GMT
Post by Deleted on Sept 23, 2007 1:30:24 GMT
might well be tom but this is what i got told on my tech2s
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WM400
Sept 23, 2007 2:25:32 GMT
Post by tubeprune on Sept 23, 2007 2:25:32 GMT
And I always thought you knew all TP Oracle has known TP for about 30 years now and concurs! OK - found out at last.  I couldn't expect to get away with it forever. |
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Oracle
In memoriam
RIP 2012
Writing is such sweet sorrow: like heck it is!
Posts: 3,234
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WM400
Sept 23, 2007 17:45:43 GMT
Post by Oracle on Sept 23, 2007 17:45:43 GMT
Oracle hasn't had any moments of fame on the small box though, just in the printed press (including his fizog).  Mind you, pinching words from the the Mr Kipling advert, he did run with TP's help & contribution "an exceedingly good [Underground] magazine" but still knows nothing even after all this time!  |
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Oracle has known TP for about 30 years now and concurs! 
I couldn't expect to get away with it forever.
