In article ,
Tom Anderson wrote:
On Tue, 31 Jan 2006, Clive D. W. Feather wrote:

We could have had them. Was it worth paying the extra for a
once-in-a-lifetime event?

Depends how much it would have cost. Here, i'll do it for free:

int trainLength = train.getNumberOfCars() ;

You don't appear to be defining how this method is implemented.
How do you do it for free?

platform.edgeDoor((2 * i)).open() ; // the front one
platform.edgeDoor(((2 * i) + 1)).open() ; // the back one

You appear to be assuming that the PEDs are individually controlled.
Perhaps the interface would better described as:
platform.edgeDoor().openAllDoors();

with the 7th set of doors unmoving by virtue of the fuse on the relevant motors
being removed[1]. Except they've but the fuse back now, so all the
doors move. Removing the fuse is obviously cheaper than adding
the controls needed to open each door individually.

Cheers, Mike.

[1] or something nice and simple and cheap.

--
RIP Morph (1977-2005)

Clive D. W. Feather wrote:
In article . com,
writes
It seems incredible that the platform edge doors couldn't be programmed
for a 6 or 7 coach train and have some sort of detection system.

We could have had them. Was it worth paying the extra for a
once-in-a-lifetime event?

--
Clive D.W. Feather | Home:
Tel: +44 20 8495 6138 (work) | Web: http://www.davros.org
Fax: +44 870 051 9937 | Work:
Please reply to the Reply-To address, which is:

I would have thought that wanting to run trains of different formations
during the lifetime of PED's on the Jubileee line was quite high.
Let's say that at some time in the future there is a shortage of
rolling stock due to some sort of defect, overcoming this by reducing
the formation is now out on the question.
But hey, whats inconveniencing a few tens of thousands of passengers
compared to spending a few thousand pounds, in the context of the
billions spent on building the Jubilee Line.

Kevin

In article , Tom
Anderson writes
Depends how much it would have cost. Here, i'll do it for free:

int trainLength = train.getNumberOfCars() ;

cxx: error: method not found

That ought to be tested before it goes into production use, though.

End of "free".

[And why are you using free in C++ anyway?]

--
Clive D.W. Feather | Home:
Tel: +44 20 8495 6138 (work) | Web: http://www.davros.org
Fax: +44 870 051 9937 | Work:
Please reply to the Reply-To address, which is:

On Tue, 31 Jan 2006 20:25:55 +0000, "Clive D. W. Feather"
wrote:

In article . com,
writes
It seems incredible that the platform edge doors couldn't be programmed
for a 6 or 7 coach train and have some sort of detection system.

We could have had them. Was it worth paying the extra for a
once-in-a-lifetime event?

It was obviously going to happen at some point, since they designed
for 7 cars. You'd have thought they'd have planned ahead.

--
James Farrar
. @gmail.com

On Wed, 1 Feb 2006 02:04:58 +0000, Tom Anderson
wrote:

throw new MalformedTrainException

Isn't that what passengers do when they hear "due to late running,
this train terminates here. All change please"?

--
James Farrar
. @gmail.com

On Wed, 1 Feb 2006, Mike Bristow wrote:

In article ,
Tom Anderson wrote:
On Tue, 31 Jan 2006, Clive D. W. Feather wrote:

We could have had them. Was it worth paying the extra for a
once-in-a-lifetime event?

Depends how much it would have cost. Here, i'll do it for free:

int trainLength = train.getNumberOfCars() ;

You don't appear to be defining how this method is implemented.
How do you do it for free?

I was naively assuming that there's a computer somewhere which knows these
things.

platform.edgeDoor((2 * i)).open() ; // the front one
platform.edgeDoor(((2 * i) + 1)).open() ; // the back one

You appear to be assuming that the PEDs are individually controlled.
Perhaps the interface would better described as:
platform.edgeDoor().openAllDoors();

with the 7th set of doors unmoving by virtue of the fuse on the relevant
motors being removed[1]. Except they've but the fuse back now, so all
the doors move. Removing the fuse is obviously cheaper than adding the
controls needed to open each door individually.

Ah, i see. Well, perhaps the fuses could be replaced by a fuse and a relay
(or a power transistor or whatever it is they have these days), with a
wire running back to a controller which can switch the relays on and off
remotely, under computer control (a BBC micro with a suitable program in
ROM would do the job!).

Okay, so my solution is slightly facetious, but only slightly - i don't
see how opening the right number of doors needs to be terribly expensive.

tom

--
The revolution is here. Get against the wall, sunshine. -- Mike Froggatt

On Wed, 1 Feb 2006, Clive D. W. Feather wrote:

In article , Tom Anderson
writes

Depends how much it would have cost. Here, i'll do it for free:

int trainLength = train.getNumberOfCars() ;

cxx: error: method not found

Ah, i missed the:

import uk.gov.tfl.lul.signalling.jubilee.* ;

And a couple of lines setting up the train object.

That ought to be tested before it goes into production use, though.

End of "free".

Well, yes.

[And why are you using free in C++ anyway?]

Not C++, Java - good god, you don't imagine i'd use a language with manual
memory management and pointer arithmetic in a safety-critical system, do
you?

tom

--
The revolution is here. Get against the wall, sunshine. -- Mike Froggatt

In article ,
Tom Anderson wrote:
Okay, so my solution is slightly facetious, but only slightly - i don't
see how opening the right number of doors needs to be terribly expensive.

The testing required to prove a safty-critical piece of kit would,
I expect, be larger than you think.

By making something more complicated, you tend to reduce its
reliablity, so you need to factor in the cost of increased downtime
and increased maintaince over the lifetime of the kit.

Don't get me wrong: I think they could have done a number of things
that would have worked, been safe, kept the line open, and probably
cost less than shutting the line[1]. But I'm prepared to admit
that I don't know all that much about runnin a railway, and could
be wrong.


[1] eg run with 6 doors that open at the Stratford end of all platforms,
and lock out the car at the other end of the train. On the flag day,
run with 7 doors that open on the platforms, and ban 6-car trains.

--
RIP Morph (1977-2005)

In message , Tom
Anderson writes

Not C++, Java - good god, you don't imagine i'd use a language with
manual memory management and pointer arithmetic in a safety-critical
system, do you?


Well, yes, actually, because you know what you have and can test and fix
every piece of it, rather than relying on an over-complicated
third-party runtime which has almost certainly not had adequate testing
for a safety-critical environment. I'd rather be using C, or a
Forth-type language.

--
1089

wrote:
Bob wrote:

http://www.guardian.co.uk/Business/s...698519,00.html

Bob


Classic.

The requirement was imposed because of concerns that passengers might
become confused and fall on to the track while attempting to board a
seventh carriage on trains which only had six.

Kevin


And what is interesting is that they did not cite where this requirement
was to be found. Can't help thinking that perhaps the requirement was
something else but if someone can find an exact reference I'm happy to
be wrong.

--
To contact me take a davidhowdon and add a @yahoo.co.uk to the end.