Terry Morgan and longer Jubilee line trains
 

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

Bob

Terry Morgan and longer Jubilee line trains
 

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

Terry Morgan and longer Jubilee line trains
 

wrote in message
oups.com...

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


What about partially sighted or blind passengers who may not notice?

Terry Morgan and longer Jubilee line trains
 

"Robert McCall" wrote in message
...

wrote in message
oups.com...

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


What about partially sighted or blind passengers who may not notice?

Or the drunk...

Terry Morgan and longer Jubilee line trains
 

Terry Morgan and longer Jubilee line trains
 

wrote in message
oups.com...

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


Wasn't this to do with the limitations of the platform edge doors at the new
stations, which couldn't be altered to open dependent on train length, ie
not exactly comparable with the situation on the Subsurface railway. Still
seems possible to have dealt with the issue even if platform staff had to
stand by the doorways for a few days.

Paul

Terry Morgan and longer Jubilee line trains
 

Paul Scott wrote:
wrote in message
oups.com...

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


Wasn't this to do with the limitations of the platform edge doors at the new
stations, which couldn't be altered to open dependent on train length, ie
not exactly comparable with the situation on the Subsurface railway. Still
seems possible to have dealt with the issue even if platform staff had to
stand by the doorways for a few days.

Paul

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.
Last week a space probe that has been in deep space for several years
having collected dust from the tail of a comet landed back on earth but
we can't have platform edge doors that can cope with variable train
lengths.

Kevin

Terry Morgan and longer Jubilee line trains
 

wrote in message
ups.com...

Wasn't this to do with the limitations of the platform edge doors at the
new
stations, which couldn't be altered to open dependent on train length, ie
not exactly comparable with the situation on the Subsurface railway.
Still
seems possible to have dealt with the issue even if platform staff had to
stand by the doorways for a few days.

Paul

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.
Last week a space probe that has been in deep space for several years
having collected dust from the tail of a comet landed back on earth but
we can't have platform edge doors that can cope with variable train
lengths.

Kevin

Of course had they been programmable, H&S would probably have insisted on a
weeks testing with empty trains of varying length anyway...

Paul

Terry Morgan and longer Jubilee line trains
 

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:

Terry Morgan and longer Jubilee line trains
 

On Tue, 31 Jan 2006, 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?

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

int trainLength = train.getNumberOfCars() ;
if ((trainLength 6) || (trainLength 7))
{
throw new MalformedTrainException(train, "bad number of cars") ;
}
for (int i = 0 ; i trainLength ; ++i)
{
// assumes this is a headstop, if that's what it's called
// tailstop is not much more complicated
platform.edgeDoor((2 * i)).open() ; // the front one
platform.edgeDoor(((2 * i) + 1)).open() ; // the back one
}

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

tom

--
Who would you help in a fight, Peter van der Linden or Bill Gates?

Terry Morgan and longer Jubilee line trains
 

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)

Terry Morgan and longer Jubilee line trains
 

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

Terry Morgan and longer Jubilee line trains
 

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:

Terry Morgan and longer Jubilee line trains
 

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

Terry Morgan and longer Jubilee line trains
 

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

Terry Morgan and longer Jubilee line trains
 

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

Terry Morgan and longer Jubilee line trains
 

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

Terry Morgan and longer Jubilee line trains
 

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)

Terry Morgan and longer Jubilee line trains
 

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

Terry Morgan and longer Jubilee line trains
 

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.

Terry Morgan and longer Jubilee line trains
 

On Thu, 2 Feb 2006, Mike Bristow wrote:

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.

I realise that it would be large - i just don't think it would be large
enough to be a significant fraction of the cost of the whole seven-car
project. I could well just be being wildly over-optimistic here.

Playing devil's advocate here - how safety-critical is this? I mean, the
least safe failure mode i can think of is the door being open, which would
leave the Jubilee in a similar state to every other tube line!

But I'm prepared to admit that I don't know all that much about runnin a
railway, and could be wrong.

Same here. But playing at armchair fat controller is a common past-time
round these parts!

[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.

Good idea. I did wonder why this wasn't done. Maybe because of the risk of
people getting the cars unlocked, then being unable to get out?

tom

--
Better to die on your feet than live on your knees. -- Emiliano Zapata

Terry Morgan and longer Jubilee line trains
 

In article ,
Tom Anderson wrote:
On Thu, 2 Feb 2006, Mike Bristow wrote:
The testing required to prove a safty-critical piece of kit would, I
expect, be larger than you think.

I realise that it would be large - i just don't think it would be large
enough to be a significant fraction of the cost of the whole seven-car
project.

Wrong question: the right question is "is the cost of $plan more than the
cost of $otherplan".

They had a plan: shut the Jubilee down for a week. It worked.
We're arguing over implementation detail (albeit important
implementation detail).

--
RIP Morph (1977-2005)

Terry Morgan and longer Jubilee line trains
 

On Thu, 2 Feb 2006, 1089 wrote:

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.

Depends on the runtime. And on what you're doing, of course - as
Greenspun's tenth law observes, any large program includes a
reimplementation of much of the functionality of an over-complicated
runtime, so you'll generally be better off using a more sophisticated
language to start with. If you're doing something fairly simple that
doesn't need much dynamic memory, C might be better; this example is
probably in the latter class, to be honest.

I'd rather be using C, or a Forth-type language.

Or Ada - still (usually) no GC, but at least much better type-safety.

Highly entertaining article comparing Ada, C, C++ and Java to the original
Ada requirements document (used as a gold standard for a language for
serious embedded systems):

http://www.adahome.com/History/Steelman/steeltab.htm

Ada wins, Java and C++ are neck-and-neck, and C comes in last. Mostly,
though, that's because C doesn't specify thread-related stuff as part of
the language; i think C + POSIX would do a lot better.

tom

--
Better to die on your feet than live on your knees. -- Emiliano Zapata

Terry Morgan and longer Jubilee line trains
 

Tom Anderson wrote:

Playing devil's advocate here - how safety-critical is this? I mean, the
least safe failure mode i can think of is the door being open, which
would leave the Jubilee in a similar state to every other tube line!

Presumably the difference would be one of human behaviour. If people
are used to the doors opening on the covered lines meaning they can walk
through them then they may do so if this situation even though they
would never simply step off a normal platform.

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

Terry Morgan and longer Jubilee line trains
 

Mike Bristow writes:
They had a plan: shut the Jubilee down for a week. It worked.

True. But if platform-edge doors were the issue, why couldn't they
have kept the line open from Stanmore to Green Park, using whichever
trains were available each day?
--
Mark Brader, Toronto | "You can write a small letter to Grandma
| in the filename." -- Forbes Burkowski

Terry Morgan and longer Jubilee line trains
 

Mark Brader wrote:

Mike Bristow writes:
They had a plan: shut the Jubilee down for a week. It worked.

True. But if platform-edge doors were the issue, why couldn't they
have kept the line open from Stanmore to Green Park, using whichever
trains were available each day?

A better alternative for that week would've been to divert the trains of
the length that there were less of to Charing Cross.

A much better alternative would've been to lengthen all the trains
overnight! I'm sure it's something that they'd be capable of if they put
their minds and resources to it!

--
Aidan Stanger
http://www.bettercrossrail.co.uk