Mark Brader:
As a further safety aid, the tracks at the right were actually
gauntleted (interlaced), with two pairs of rails that diverged
(if my interpretation is right) at the positions o. That is, in
terms of individual rails, the layout at each o was:
-------------------------------------------------
/---------------------------------
/
-------------+-----------------------------------
/ /-----------------------------
/ /
/ /
And if a particular train started from the south face of the departure
platform, then it would use the south face of the departure platform all
day, and also the south face of the arrival platform, staying always on
the south rail of each pair.
Tom Anderson:
So each track was in fact four rails, of which only two were in use at
once? There are two logical tracks sharing the same space?
Uh-huh. This is more commonly done in locations where clearance
considerations force what would otherwise be a short section of
single track on a double-track line. Here's an old image from
Colwyn Bay in Wales: http://dewi.ca/trains/lcber/b039.jpg. Another
use is to allow wide trains to pass a platform on a track designed
for narrow trains on what would otherwise be a single track, like this
one: http://image03.webshots.com/3/0/83/44/21408344mgAUFPpzaa_ph.jpg
near Chicago.
The corresponding rails can also be set much closer, as on this narrow
Amsterdam street. You might think this was a single track at first glance:
http://www.railfaneurope.net/pix/nl/trams/Amsterdam/Combino/line_1/amsterdam_2001.jpg
One more source of danger elimnated.
How so?
No possibility of the points being set wrong, routing the train into the
wrong arrival platform, which most likely would already be occupied.
(Similarly, in situations like the Welsh and Dutch examples, no possibility
of the car going onto the wrong track and colliding head-on with another.)
No possibility of points changing under the train, either.
Is there some sort of encyclopedia of railway engineering that i could get
hold of which would save you from these questions?
Hey, what fun would that be? :-)
--
Mark Brader, Toronto | "Any story that needs a critic to explain it,
| needs rewriting." -- Larry Niven
My text in this article is in the public domain.