On Mon, 18 Jul 2005 09:21:45 GMT someone who may be Chris Tolley
wrote this:-

Why should the speed ("considerable" or otherwise) be a matter of
concern for these arms, but not for the leading one?

One way such systems can fail is if the arm breaks off. This risk is
controlled by not having arms generally not striking trainstops and
so not suffering the fatigue this involves. An arm at the front of
the train will only strike a trainstop on rare occasions.

The higher the speed that an arm strikes the trainstop the more
likely it is to fail. "BR" trains will usually be travelling at high
speed when they first encounter trainstops as they enter the LT
signalled section.


--
David Hansen, Edinburgh | PGP email preferred-key number F566DA0E
I will always explain revoked keys, unless the UK government
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