In message , John Rowland
writes

"Paul Scott" wrote in message
...

I stand to be corrected but don't think there are any
[Tyne & Wear Airport Extension] LC that are not at
stations, and therefore the train is always stationary
with the driver able to sight the LC before he sets off again.

That only works in one direction!

But you snipped Paul's first sentence in the above quote, which included
the words

all the stations seem to be split with the platforms on either
side of the level crossing.

I take that to mean ...

XXXXXXXXXXX
----------------- X ----------------
----------------- X ----------------
XXXXXXXXXX

Surely that would work in both directions?

--
Paul Terry

"Paul Terry" wrote in message
...
In message , John Rowland
writes
"Paul Scott" wrote in message
...

I stand to be corrected but don't think there are any
[Tyne & Wear Airport Extension] LC that are not at
stations, and therefore the train is always stationary
with the driver able to sight the LC before he sets off again.

That only works in one direction!

But you snipped Paul's first sentence in the above quote,
which included the words

all the stations seem to be split with the
platforms on either side of the level crossing.

[blush]

--
John Rowland - Spamtrapped
Transport Plans for the London Area, updated 2001
http://www.geocities.com/Athens/Acro...69/tpftla.html
A man's vehicle is a symbol of his manhood.
That's why my vehicle's the Piccadilly Line -
It's the size of a county and it comes every two and a half minutes

Paul Terry wrote:
writes
"Paul Scott" wrote...

I stand to be corrected but don't think there are any
[Tyne & Wear Airport Extension] LC that are not at
stations, and therefore the train is always stationary
with the driver able to sight the LC before he sets off again.

That only works in one direction!

But you snipped Paul's first sentence in the above quote, which included
the words

all the stations seem to be split with the platforms on either
side of the level crossing.

I take that to mean ...

XXXXXXXXXXX
----------------- X ----------------
----------------- X ----------------
XXXXXXXXXX

Surely that would work in both directions?

Sorry about the late response, but this intrigues me. Can anyone confirm
that that's what the setup really is? I ask because here in Adelaide
there are several split stations, but they're all...

XXXXXXXXXX
----------------- X ----------------
----------------- X ----------------
XXXXXXXXXXX

....which means that the traffic doesn't have to wait for as long.

"Aidan Stanger" wrote:

Sorry about the late response, but this intrigues me. Can anyone confirm
that that's what the setup really is?


When the Tyne & Wear Metro originally opened (in stages between 1980 and
1984), there were three level crossings on the system. Only two of these
were at stations - at Fawdon, and at Howdon. Both followed the pattern that
Paul described, with staggered platforms on either side of (and before) the
crossing, so that trains always stopped *before* crossing the roadway.

Fawdon was built from scratch (the line had been freight-only under BR, and
the previous station on the site - Coxlodge - had closed in 1929). Until it
was closed by BR in 1980, Howdon station had both platforms on the same side
of the crossing - when it reopened for the Metro in 1982, one platform had
been demolished and replaced by a new one before the crossing (the other
being retained, as it was already situated before the crossing). The third
level crossing on the system - at Kingston Park - did not have a station
when Metro services started on this section in 1981. I believe that trains
slowed, but did not stop, before crossing the roadway. However, in 1985 a
new station was opened here, and this followed the usual pattern - with
staggered platforms, each before the roadway.

All three crossings were and are "open" (ie with klaxons and flashing
lights, but without barriers). Those at Kingston Park and Fawdon were also
used by BR freight trains, which ran over this branch of the Metro until the
late 80s.


Policy must have changed over the years. When the system was extended from
Bank Foot to Airport in 1991, two more level crossings were added, and again
each was at a station - at Bank Foot (immediately beyond the former end of
the line), and at Callerton Parkway (the intermediate station on the new
extension). However, each station has *both* platforms on the same side of
the road. Airport-bound trains stop before crossing the roadway, and South
Shields-bound trains stop after crossing the roadway, at each location^.
IIRC, there is also at least one open bridleway crossing between stations on
this section.



I ask because here in Adelaide
there are several split stations, but they're all...

XXXXXXXXXX
----------------- X ----------------
----------------- X ----------------
XXXXXXXXXXX

...which means that the traffic doesn't have to wait for as long.

Why would traffic have to wait longer if they were split Fawdon-style?

Is it because the crossing has to be closed to road traffic before the train
arrives, and while it dwells in the platform? I've seen this before on
heavy rail (eg for London-bound trains at Higham's Park) - presumably
because the crossing is within the signal overlap of the station starting
signal, and therefore a train cannot be let into the platform until the
crossing is clear of road traffic in case the train overshoots.

At the three staggered stations on the T&W Metro (and also the other two
with level crossings, in the relevant direction!), trains can pull into
platforms while road traffic is still on the crossing. Lights and klaxons
don't start until a few seconds before the train completes its dwell time.
Presumably this is allowed because the platforms are set back about 50m from
the road, and because Metrocars are fitted with tramway-style magnetic track
brakes for emergency use - so bringing the relative risk of a train
overshooting onto a crossing down to acceptable levels. Hence, road traffic
delays are kept to a minimum.

Surely, with both platforms after the crossing (Adelaide-style), it is
sometimes necessary to keep the crossing closed to road traffic for an
extended period (or to close it twice in quick succession) when trains
approach from both directions roughly simultaneously? IIRC, on Tyneside in
these circumstances the train that arrived first is held in the platform a
little longer (say, for up to an extra 30 seconds), so that both trains can
cross the road together and avoid delaying road traffic any more than is
necessary.




--
MetroGnome
~~~~~~~~~~

(To email me, edit return address)





^ = This is definitely the arrangement at Callerton Parkway. I *think* this
is also the case at Bank Foot, although it is so long since I was there that
I'm now not 100% certain.

In article ,
MetroGnome writes
Is it because the crossing has to be closed to road traffic before the train
arrives, and while it dwells in the platform? I've seen this before on
heavy rail (eg for London-bound trains at Higham's Park) - presumably
because the crossing is within the signal overlap of the station starting
signal, and therefore a train cannot be let into the platform until the
crossing is clear of road traffic in case the train overshoots.

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.

--
Clive D.W. Feather, writing for himself | Home:
Tel: +44 20 8371 1138 (work) | Web: http://www.davros.org
Fax: +44 870 051 9937 | Work:
Written on my laptop; please observe the Reply-To address

"Clive D. W. Feather" wrote in message
...
In article ,
MetroGnome writes
Is it because the crossing has to be closed to road traffic before the
train
arrives, and while it dwells in the platform? I've seen this before on
heavy rail (eg for London-bound trains at Higham's Park) - presumably
because the crossing is within the signal overlap of the station starting
signal, and therefore a train cannot be let into the platform until the
crossing is clear of road traffic in case the train overshoots.

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.

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?

In message m, Martin
Underwood writes
"Clive D. W. Feather" wrote in message
...
In article ,
MetroGnome writes
Is it because the crossing has to be closed to road traffic before the
train
arrives, and while it dwells in the platform? I've seen this before on
heavy rail (eg for London-bound trains at Higham's Park) - presumably
because the crossing is within the signal overlap of the station starting
signal, and therefore a train cannot be let into the platform until the
crossing is clear of road traffic in case the train overshoots.

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.

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?

It has the advantage that the signal at the end of the platform can be
cleared, so the preceding signal shows green or double-yellow and the
train can enter the station at a reasonable speed rather than having to
slow down to a crawl after the single yellow (as is required by
'professional driving' policies).
--
Spyke
Address is valid, but messages are treated as junk. The opinions I express do
not necessarily reflect those of the educational institution from which I post.

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

"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)?



--
MetroGnome
~~~~~~~~~~

(To email me, edit return address)

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.

--
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