Technology for its own sake?
 

On Fri, 24 Sep 2004 04:46:28 -0700, David E. Belcher wrote:

SDO

Sorry for being think - what does SDO stand for?

Ta

Timbo

Technology for its own sake?
 

"Solar Penguin" wrote in message
...
...And the buffet serves something that's almost, but not quite, entirely
unlike tea. (Oh, wait. That already happens...)

At least you won't have to flollop with a matress on the platform if the
doors don't open... (Radio 4, H2G2 repeat, 11pm tonight (Thursday)).

Technology for its own sake?
 

--- "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.

Technology for its own sake?
 

"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.

Technology for its own sake?
 

Tim wrote:

Sorry for being think - what does SDO stand for?

Selective Door Opening

Chris
--
Chris J Dixon Nottingham UK


Have dancing shoes, will ceilidh.

Technology for its own sake?
 

--- "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?

Technology for its own sake?
 

On Thu, 23 Sep 2004 22:32:22 UTC, TP wrote:

: James Christie wrote:
:
: The Russians have their own system called GLASNOSS

: You have to be joking.

Maybe he is. I think it's called GLONASS.

Ian

Technology for its own sake?
 

On Thu, 23 Sep 2004 18:25:33 UTC, "Gavin Hamilton"
wrote:

: It's been somewhat better than that for a while, since the "random error"
: was removed. IME the error is probably nearer 2 metres. Though the powers
: that be can reintroduce the random factor, or turn it off entirely, should
: they feel the need.

You have to be careful not to confuse the random precison errors with
the unrandom accuray ones. Civilian GPS is designed to be precise to
about +/- 10m, whereas military GPS, which uses different signals, is
precise to +/- 1m. Those errors are random - there is nothing you can
do about them. Selective availability was a deliberate degradation of
accuracy, done by effectively instructing satellites to tell porkies
in their signals, and thereby displace all GPS positions in a
particular area by an ordained amount. That's what doesn't happen
(much) any more, but the precision errors remain.

Ian
--

Technology for its own sake?
 

Solar Penguin wrote to uk.transport.london on Fri, 24 Sep 2004:


--- "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?

I don't think it does. My mother was travelling on a train from Clapham
Junction to Arundel; I don't know what had gone wrong, but the train she
was aiming for was cancelled, and the following train was only 4
carriages, not 8. As you can imagine, it was packed out, but luckily
someone gave her their seat, so she was all right. Anyway, she told me
afterwards that the electronic displays thought they were going to
London, not away from it, so that "The next station is" was totally out
of phase with reality! She said it was very funny.
--
"Mrs Redboots"
http://www.amsmyth.demon.co.uk/
Website updated 11 September 2004

Technology for its own sake?
 

Ross wrote to uk.transport.london on Fri, 24 Sep 2004:

And to further complicate matters, retention tanks require that the
contents be emptied, which means that they need somewhere with a
suitable cleaning pan and that in turn means that it's unlikely that
tanks can be cleared at every poxy little stabling point at which
trains get left overnight. In the case of the 170, the toilets will
lock themselves out once the retention tanks are full.

I think it is the same everywhere. Although, to be fair, Eurostars seem
to manage to have loos that flush for the whole journey and so,
normally, does the Shuttle. But there, I suspect, if one loo locks
itself out of service, the others don't, unlike on surface-only trains.
--
"Mrs Redboots"
http://www.amsmyth.demon.co.uk/
Website updated 11 September 2004

Technology for its own sake?
 

JRS: In article , dated Thu, 23
Sep 2004 18:58:46, seen in news:uk.transport.london, James Christie
posted :

With difficulty, because GPS has an accuracy of +/- 100m, unless of
course you are using Differential GPS, but that is mainly a maritime
system.

Differential GPS with respect to a set on the platform (or station)
seems an obvious move - even deals properly with landslides.

But I believe that a platform is the only extended object which comes
that near to just under a train door; if so, use a pair of solid object
detectors below door level, one at each side of the doorway.

Sonar or radar could be used. ISTM likely that if a suitable
electromagnetic structure were fixed to platform edges (e.g. a
perforated metallic strip) then one might use resonant reflection, and
be platform-specific.

--
© John Stockton, Surrey, UK. / ©
Web URL:http://www.merlyn.demon.co.uk/ - FAQish topics, acronyms, & links.
Correct = 4-line sig. separator as above, a line precisely "-- " (SoRFC1036)
Do not Mail News to me. Before a reply, quote with "" or " " (SoRFC1036)

Technology for its own sake?
 

Boltar wrote:

I read apparently that Southern had been having problems with its train doors
not opening on stations north of the Thames because these hadn't been
programmed into the database that uses GPS to know where it is! Is it just me
or is having some GPS controlled database system being used to open the
bloody doors just a teensy bit overkill?? Do they think the driver is
too stupid to know when he's at a station and might try to open them when he's
bowling along at 60?? Sure have some sort of interlock that prevents them
opening when the train is moving but for gods sake , was this implemented just
to keep some technicians in work? And what happens during an emergency?
What next , GPS controlled toilets that won't flush on certain parts of the
network with live networked updates of the turd count at every section?!

No wonder money in the rail industry is in short supply if they're wasting
funds on stupid systems such as this. Someone tell me its not true...

B2003

I don't know why the main line rail companies don't just adopt the
Underground's Correct Side Door Enable system, that prevents doors being
opened on the wrong sides of the train. It can cope with double-sided
platforms, bi-directional platforms, and also automatic cutting in and
cutting out of doors on short platforms. Sorted. Why devise something
over the top to do the same job?

Lee

Technology for its own sake?
 

"Ian Johnston" wrote in message
news:cCUlhtvFIYkV-pn2-KSqR179sj7HU@localhost...

You have to be careful not to confuse the random precison errors with
the unrandom accuray ones. Civilian GPS is designed to be precise to
about +/- 10m, whereas military GPS, which uses different signals, is
precise to +/- 1m. Those errors are random - there is nothing you can
do about them. Selective availability was a deliberate degradation of
accuracy, done by effectively instructing satellites to tell porkies
in their signals, and thereby displace all GPS positions in a
particular area by an ordained amount. That's what doesn't happen
(much) any more, but the precision errors remain.


I have experienced an distinct improvement in accuracy over the last few
years but I am also aware that in certain circumstances GPS is not to be
relied upon. Such events occur, for example, in narrow valleys where the
signals can be "deflected" for want of a better description so GPS wouldn't
work very well in cuttings - or tunnels for that matter.

SA would not be very effiective if all satellites were to displace their
positions by the same amount in the same direction - AFAIK each satellite
had its own displacement which was random - watching a GPS position on a
chart plotter was quite interesting in those days. Now the position doesn't
move and will even plot a position on the correct side of a pontoon.

However when the authorities are playing silly b*ggers with the signal it
tends to be anounced in navigation warnings.....

G

Technology for its own sake?
 

"Tim" wrote in message .. .
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?

Never mind that , GPS is easily blocked by obstructions such as trees ,
embankments , bridges etc. And as for tunnels... Still , on the bright side
that means LU won't be using it for the doors anytime soon :)

B2003

Technology for its own sake?
 

Technology for its own sake?
 

--- "Annabel Smyth" wrote:

Solar Penguin wrote to uk.transport.london on Fri, 24 Sep 2004:


So how does it keep the count of "The next station is..." displays
updated when that happens?

I don't think it does. My mother was travelling on a train from
Clapham Junction to Arundel; I don't know what had gone wrong,
but ... she told me afterwards that the electronic displays thought
they were going to London, not away from it, so that "The next
station is" was totally out of phase with reality! She said it was
very funny.

Oh... Looks like there are serious problems with the whole thing then. No
wonder the trains can't decide which doors to open if they don't even know
which way they're going! Let's hope they get these bugs sorted soon.

Technology for its own sake?
 

On Fri, 24 Sep 2004 15:56:21 +0100, Annabel Smyth wrote in
, seen in uk.railway:

But there, I suspect, if one loo locks
itself out of service, the others don't, unlike on surface-only trains.

170s don't do this; only the affected toilet will lock itself out. I
suspect it's something that differs according to the unit design.
--
Ross

From & reply-to addresses will bounce. Reply to the group.

Technology for its own sake?
 

On 24 Sep 2004 14:14:57 -0700, MIG wrote in
, seen in uk.railway:

[snip]
If any on-train information system
crashes just after the last piece of locational information it
receives, whether from GPS or anything else, is anyone going to bother
about it or warn the passengers?

Depends if the staff are even aware! Again talking about 170s, it's
not at all unusual for the drivers display to show correct data whilst
all displays bar those in the front coach show something else
entirely. :(

--
Ross

From & reply-to addresses will bounce. Reply to the group.

Technology for its own sake?
 

"Tim" wrote in message .. .
On Fri, 24 Sep 2004 04:46:28 -0700, David E. Belcher wrote:

SDO

Sorry for being think - what does SDO stand for?


Oops - sorry Tim, should've made it clearer (Selective Door Opening,
for the record).

David E. Belcher

Technology for its own sake?
 

On Fri, 24 Sep 2004 10:37:17 +0100, Matthew Wild
said:

the USAians were
complaining that the main signal would sit right on their military band and
they wouldn't be able to locally degrade Galileo without doing the same to
their own military.

Sounds like a feature, not a bug.

--
David Cantrell | http://www.cantrell.org.uk/david