On Thu, 23 Sep 2004 13:57:48 +0000, Charles Middleton wrote:


"Jack Taylor" wrote in message
...

GPS is only there to cope with short platforms and to tell the train
*which*
doors to open. For example, when stopping an eight-car train at a
seven-car-length platform the software will lock out the rearmost
doors,
to
prevent passengers from hurling themselves onto the track. Apparently
it's necessary in these litigious days when anyone stupid enough to
attempt to alight from a door that is not at a platform will try to sue
the TOC,
rather
than accept personal responsibility for doing something so dumb in the
first
place.

What if it was dark? Some platforms are very poorly lit. Seems like a
good idea to me.

CM.

Here's what I would propose:

Use a passive RF responder stuck on the side of the platform edges - you
know, like those things that tell the shop if you've been nicking stuff.

I think the RF responders are dirt cheap so the main expense is kitting
out transponders adjacent to each door on the train.

Simple concept though - one transponder per door and it interlocks
directly with that door's local circuit. The RF is short range and you
just stick loads of the passive tags all the way along each platform edge.

Simple - much simpler than GPS. The RF tags don't mind if they're
wet/dirty/painted etc. They are also very thin. OK - there's an outfit
cost to install the tags at every station - but it's a quick job -
probably almost as quick as painting the white lines.???

Hmm

Timbo