Deleted
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Post by Deleted on Mar 31, 2007 20:34:38 GMT
While on a quick mosey down to Amersham and Chesham to admire Metronet's handiwork I noticed that Chalfont pfm3 has acquired a strange and unusual tripcock testing installation.
Somehow, the S&T folks have managed to wire up two tripcock testers in such a way that an approaching A stock actually manages to test both tripcocks at the same time! I literally watched the North End and South End tester lamps go out simultaneously as the front tripcock and rear tripcock plunged the testers cleanly...
How was this unusual installation accomplished?
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Post by c5 on Mar 31, 2007 20:46:51 GMT
The idea was actually thought up by an LUL DMT.
It works in the same way as a normal tester. It merely tests that the tripcock is in present and in alignment.
There is then a double light to extinguish to indicate which (hopefully) both tripcocks tested okay.
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Post by Deleted on Mar 31, 2007 20:50:40 GMT
In the same way as a normal tester. It merely tests that the tripcock is in position and alignment. The idea was actually thought up by an LUL DMT. There is then a double light to extinguish to indicate which (hopefully) both tripcocks tested okay. Is it really that simple? I would have thought that sending a tripcock over a tester in reverse would result in a back trip. |
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Tom
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Post by Tom on Mar 31, 2007 20:51:49 GMT
While on a quick mosey down to Amersham and Chesham to admire Metronet's handiwork I noticed that Chalfont pfm3 has acquired a strange and unusual tripcock testing installation. Somehow, the S&T folks have managed to wire up two tripcock testers in such a way that an approaching A stock actually manages to test both tripcocks at the same time! I literally watched the North End and South End tester lamps go out simultaneously as the front tripcock and rear tripcock plunged the testers cleanly... How was this unusual installation accomplished? Very easily - because I was one of the testers who commissioned them! The circuits are identical to a standard motorised tester, all it needed was a bit of calculation to work out the tripcock to tripcock distance and then install them that distance apart. (Actually, they went in 0.5m out but it doesn't matter). The 'wrong' tester had to be turned through 180 o to prevent a back-trip and in consequence some special rail chairs to be installed to facilitate installation of the tester IIRC. As for the tripcock, it doesn't make any difference if it is being tested in the normal direction or not. |
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Post by Deleted on Mar 31, 2007 20:54:30 GMT
Well you certainly succeeded - both testers clattered at the same time and both lights went out at the same time. I was just surprised to see such an innovative and clever installation of a bog-standard tester.
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