| Subject: |
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Re: SIGNAL FAILURES |
| Name: |
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District Dave |
| Date Posted: |
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Feb 22, 05 - 7:22 PM |
| Message: |
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Well, that question's certainly brief and to the point!
There are many reasons why signals fail - some are to do with the actual signal itself, some are to do with equipment that is associated with it - in fact it is more often this than the actual signal 'head'.
I'd suggest that you have a look at the following page, an you'll start to get some feeling for the complexity of signalling equipment. Visit http://www.railway-technical.com/sigtxt2.html
If any one component, wire, cable, trainstop or associated set of points (and these are just a few items that are involved) as described on those pages has a problem, a signal will remain at or return to Danger. It's all part of the 'fail safe' method on which any railway works.
As far as London Underground is concerned there are a number of factors. There are thousands of signals; signals work on a combination of equipment; some parts of the system are old and due for renewal. If any one of these factors has a problem, you have a failure.
I'm afraid that's a very short answer to a very complex question. |
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