"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.