"Clive D. W. Feather" wrote:

No: an open level crossing is not counted as an obstruction in the
overlap (unless, of course, there's a problem such as a broken-down
car), so trains can be signalled up to a red signal right at the
crossing.

Thanks. What exactly do you mean by an "open" level crossing?

Do you mean that Open level crossings (ie those without gates or barriers)
don't count crossing road traffic as an obstruction, but level crossings
*with* gates or barriers do? This might account for the different practices
I've observed on the T&W Metro (no barriers) and at Higham's Park (full
barriers). Or do you mean that *any* level crossing that is open for road
traffic to cross the line (whether or not it has gates or barriers) does not
count as an obstruction in the overlap?

If the latter, is any signalling consideration given to protecting road
traffic from trains overshooting, even if such protection isn't formally
part of the signal overlap (eg, the formal overlap extends 400m beyond the
signal, but the level crossing only has to be closed to road traffic before
the train arrives if it is less than 200m from the signal)?



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MetroGnome
~~~~~~~~~~

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In article , MetroGnome
writes
No: an open level crossing is not counted as an obstruction in the
overlap (unless, of course, there's a problem such as a broken-down
car), so trains can be signalled up to a red signal right at the
crossing.

Thanks. What exactly do you mean by an "open" level crossing?

One open to road traffic to cross the line, irrespective of the crossing
tyoe.

If the latter, is any signalling consideration given to protecting road
traffic from trains overshooting, even if such protection isn't formally
part of the signal overlap

Not per se. However, an AHB will trigger if a train passes the
protecting signal at red, and similar signalling controls may be
installed at other crossing types.

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Clive D.W. Feather, writing for himself | Home:
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Fax: +44 870 051 9937 | Work:
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In article m, Martin
Underwood writes
Really? I thought that it was standard practice to close a level crossing if
it was just beyond the end of a platform in case the train overshot and
strayed onto the crossing. Certainly that's what's done with London-bound
trains at Sunningdale and Reading-bound trains at Egham.

Or are you saying that it *is* done, but that it's for safety rather than
purely signalling reasons?

Or for operational reasons - it means you can dispatch the train that
little bit quicker.

It might also be put into the signalling controls at individual
locations following a risk assessment; I just know it isn't a global
requirement.

--
Clive D.W. Feather, writing for himself | Home:
Tel: +44 20 8495 6138 (work) | Web: http://www.davros.org
Fax: +44 870 051 9937 | Work:
Written on my laptop; please observe the Reply-To address