Some weeks back I asked LUL via the TfL website why the dot matrix
indicators on the Westbound platform at Turnpike Lane can only display
details of the next train within one minute of it arriving. I got the
following reply back today:

"We recognise that the provision of real-time information at Turnpike
Lane station via the dot matrix information screens could be better. The
reason for the lack of information on the westbound platform is because
trains are constantly entering service at Arnos Grove where there is a
depot. In addition to this there are sidings at Wood Green where trains
are often reversed from eastbound to westbound. The information for the
indicator boards is picked up from signals sent by the track and
therefore with trains entering from different areas it is not possible
for the boards to show any more than the next train. This is also the
case at Bounds Green and Wood Green. Until the technology is upgraded
this will always be the case."

Not very impressive, I have to say. So it begs the question if the best
they can do is base information only once a train leaves Wood Green,
then why bother at all with any equipment at all?

--
Phil Richards, London, UK
3,600+ railway photos since 1980 at:
http://europeanrail.fotopic.net
http://britishrail.fotopic.net