"John Rowland" wrote in message
...

The obvious solution seems to be individual doors which check that there
is
a platform adjacent before opening. The basic idea seems very easy to
implement, although a foolproof system which could never mistake the sides
of a bridge for a platform might be harder to implement, but in
combination
with driver control it should be safe enough.

Something along the lines of a transponder at the start of each platform
which is detected by each door and enables the doors on the appropriate
side, and another one at the end of each platform which disables each door.
Other interlocking means that doors cannot actually open until the train has
stopped, and failsafe precautions could cancel the enabling if the train
hasn't stopped within, say, one minute of passing the transponder. Some
complications for platforms on reversible lines, but I can't help thinking
that something like this has the potential for being more reliable than the
GPS technology (Can GPS identify which line the train is on if adjoining
platforms are different lengths?)
Peter

"Peter Masson" wrote in message
...
"John Rowland" wrote in message
...

The obvious solution seems to be individual doors which
check that there is a platform adjacent before opening.

Something along the lines of a transponder at the start
of each platform which is detected by each door and
enables the doors on the appropriate side, and another
one at the end of each platform which disables each door.
Some complications for platforms on reversible lines

Ware springs to mind, and most termini. That sounds high-tech enough to
break down a lot, and requires fitting of kit at stations, which are the
most easily vandalised part of the railway. I was thinking of a projecting
metal arm under each train door which prods the platform.

--
John Rowland - Spamtrapped
Transport Plans for the London Area, updated 2001
http://www.geocities.com/Athens/Acro...69/tpftla.html
A man's vehicle is a symbol of his manhood.
That's why my vehicle's the Piccadilly Line -
It's the size of a county and it comes every two and a half minutes

John Rowland wrote:
"Peter Masson" wrote in message
...
"John Rowland" wrote in
message ...

The obvious solution seems to be individual doors which
check that there is a platform adjacent before opening.

Something along the lines of a transponder at the start
of each platform which is detected by each door and
enables the doors on the appropriate side, and another
one at the end of each platform which disables each door.
Some complications for platforms on reversible lines

Ware springs to mind, and most termini. That sounds high-tech enough
to break down a lot, and requires fitting of kit at stations, which
are the most easily vandalised part of the railway. I was thinking of
a projecting metal arm under each train door which prods the platform.

Is it too easy to simply extend the platform?

John Rowland wrote:

"Peter Masson" wrote in message
...
"John Rowland" wrote in message
...

The obvious solution seems to be individual doors which
check that there is a platform adjacent before opening.

Something along the lines of a transponder at the start
of each platform which is detected by each door and
enables the doors on the appropriate side, and another
one at the end of each platform which disables each door.
Some complications for platforms on reversible lines

Ware springs to mind, and most termini. That sounds high-tech enough to
break down a lot, and requires fitting of kit at stations, which are the
most easily vandalised part of the railway. I was thinking of a projecting
metal arm under each train door which prods the platform.

Considering the range of actual platform dimensions, that is
quite a large prod. Plus all the gear to ensure it is proved
retracted and locked whilst the train is moving.....

Chris
--
Chris J Dixon Nottingham UK


Have dancing shoes, will ceilidh.

Chris J Dixon wrote:

Ware springs to mind, and most termini. That sounds high-tech
enough to break down a lot, and requires fitting of kit at
stations, which are the most easily vandalised part of the
railway. I was thinking of a projecting metal arm under each
train door which prods the platform.

Considering the range of actual platform dimensions, that is
quite a large prod. Plus all the gear to ensure it is proved
retracted and locked whilst the train is moving.....

Or one of those detector thingies they have on the back of BMWs to
detect an obstruction whilst you're backing..

No moving parts.

--
Chris Game

"Hopefully the net-dwelling paranoid delusional conspiracy theorists
won't descend upon me " -- Chris Pratley, MSFT.

--- "Chris Game" wrote:

Or one of those detector thingies they have on the back of BMWs to
detect an obstruction whilst you're backing..

No moving parts.


Why bother with a hardware solution at all? It can all be done with
software.

The onboard computer already has a list of stations that the train will be
calling at, for the scrolling electronic displays: "This train calls at..."
It also has to keep count of which stations it has already called at, so it
can update the displays each time: "The next station is..."

Just use that information to decide whether or not to open the doors at each
station. Problem solved.

"Solar Penguin" wrote in message
...

The onboard computer already has a list of stations that the train will be
calling at, for the scrolling electronic displays: "This train calls
at..."
It also has to keep count of which stations it has already called at, so
it
can update the displays each time: "The next station is..."

Just use that information to decide whether or not to open the doors at
each
station. Problem solved.

Until a security alert closes a station so the train doesn't stop there and
then the count is off by one.

Dave.

--- "Dave Liney" wrote:


Just use that information to decide whether or not to open the doors
at each station. Problem solved.

Until a security alert closes a station so the train doesn't stop there
and then the count is off by one.


So how does it keep the count of "The next station is..." displays updated
when that happens? Presumably the driver just presses a button (or a
touch-screen display or whatever) to update the count and let it know the
train's not stopping. Or maybe the signal box does it by remote control.
Or something.

The details don't matter. The important thing is that there already has to
be some way of keeping the station count updated even when GPS isn't
working. So why not use that for the doors as well?

On Thu, 23 Sep 2004 15:57:55 +0000, Peter Masson wrote:

(Can GPS identify which line the train is on if adjoining
platforms are different lengths?)

Not with any certainty.

Of course, what happens if the Pentagon decided to turn off GPS for
civilian use without warning (which they've always stated they have the
right to do)?

Or worse, they have a war and introduce deliberate errors into the system
designed to confuse the enemy?

I can see it now on the 9:24 from Tonbridge: "We will shortly be arriving
at Copenhagen, please mind the step"

I know that Europe is going to deploy it's own GPS sats, but I don't know
when that will be.

Timbo

In message , Tim
writes
On Thu, 23 Sep 2004 15:57:55 +0000, Peter Masson wrote:

(Can GPS identify which line the train is on if adjoining
platforms are different lengths?)

Not with any certainty.

Of course, what happens if the Pentagon decided to turn off GPS for
civilian use without warning (which they've always stated they have the
right to do)?

Or worse, they have a war and introduce deliberate errors into the system
designed to confuse the enemy?

I can see it now on the 9:24 from Tonbridge: "We will shortly be arriving
at Copenhagen, please mind the step"

I know that Europe is going to deploy it's own GPS sats, but I don't know
when that will be.

Timbo

The European system is already being deployed, the first satellite is
already up (of course you need at least 4 for a good position),
forgotten the name of the system though..
The Russians have their own system called GLASNOSS and the Chinese have
also started sending up satellites so they have their own version as
well.
--
Regards,

James Christie

"In the beginning the Universe was created. This has made a lot of people very
angry and been widely regarded as a bad move."
- Douglas Adams