In article , ] (Steve
Fitzgerald) wrote:
In message ,
writes
What seems to be rare on LU is three aspect signals. There used to be
one at the entrance to the Southbound platform at East Putney but that
might be BR practice.
On LU They are generally speed controlled signals and work in a
subtly different way although they are still stop signals and have
a train stop.
If they show green, there is a clear route set and no speed
checking is in place.
If they show red, speed checking is in place and the signal will
show a yellow aspect and the train stop will drop when the train's
speed has been proved below a set figure.
They are mainly used to protect reduced overlaps on signals to
ensure a train doesn't go thundering through an area with the
potential risk of collision.
LU rules could have applied at East Putney then, with the speed control
for the approach to the junction at the platform ends.
All speed control signals seem to work in slightly different ways
depending on the local requirements and road learning includes
these nuances.
Of course where we share with BR then their signalling practices
are in force.
The example at East Putney was on non-shared track but I think has been
removed. It may have dated from the days when some trains non-stopped East
Putney.
--
Colin Rosenstiel