In message , at 20:05:28
on Thu, 9 Sep 2010, remarked:

You would have thought the signal allowing trains out of the bay
platform would be interlocked to the points being set correctly for the
route over the crossover, wouldn't you?

Even in the presence of a fault condition (which they've apparently
admitted)?
--
Roland Perry

On Fri, 10 Sep 2010 08:53:12 +0100
Roland Perry wrote:
In message , at 20:05:28
on Thu, 9 Sep 2010, remarked:

You would have thought the signal allowing trains out of the bay
platform would be interlocked to the points being set correctly for the
route over the crossover, wouldn't you?

Even in the presence of a fault condition (which they've apparently
admitted)?

So much for signals being failsafe. Failsafe unless the failsafe fails.
Which it obviously did.

B2003

wrote in message

On Fri, 10 Sep 2010 08:53:12 +0100
Roland Perry wrote:
In message , at
20:05:28 on Thu, 9 Sep 2010, remarked:

You would have thought the signal allowing trains out of the bay
platform would be interlocked to the points being set correctly for
the route over the crossover, wouldn't you?

Even in the presence of a fault condition (which they've apparently
admitted)?

So much for signals being failsafe. Failsafe unless the failsafe
fails. Which it obviously did.

Surely it was still failsafe? No trains were signalled to collide with
each other.

On Fri, 10 Sep 2010 11:38:30 +0100
"Recliner" wrote:
wrote in message

On Fri, 10 Sep 2010 08:53:12 +0100
Roland Perry wrote:
In message , at
20:05:28 on Thu, 9 Sep 2010, remarked:

You would have thought the signal allowing trains out of the bay
platform would be interlocked to the points being set correctly for
the route over the crossover, wouldn't you?

Even in the presence of a fault condition (which they've apparently
admitted)?

So much for signals being failsafe. Failsafe unless the failsafe
fails. Which it obviously did.

Surely it was still failsafe? No trains were signalled to collide with
each other.

Only because the oncoming train was still had 1km and some signals between it
and the station. If it had been 100 metres away we could be looking at a very
different situation.

B2003

wrote in message

On Fri, 10 Sep 2010 11:38:30 +0100
"Recliner" wrote:
wrote in message

On Fri, 10 Sep 2010 08:53:12 +0100
Roland Perry wrote:
In message , at
20:05:28 on Thu, 9 Sep 2010,
remarked:

You would have thought the signal allowing trains out of the bay
platform would be interlocked to the points being set correctly
for the route over the crossover, wouldn't you?

Even in the presence of a fault condition (which they've apparently
admitted)?

So much for signals being failsafe. Failsafe unless the failsafe
fails. Which it obviously did.

Surely it was still failsafe? No trains were signalled to collide
with each other.

Only because the oncoming train was still had 1km and some signals
between it and the station. If it had been 100 metres away we could
be looking at a very different situation.

Not as I understand it. After all, Tube trains routinely follow each
other all the time, just a few hundred meters apart. They are signalled
along the same route, but the signals also stop them occupying the same
sections. So in this case, even if the trains were on a collision
course, surely the signals (and train stops) would actually have stopped
them approaching each other too closely?

On Sep 10, 11:59*am, "Recliner" wrote:
wrote in message





On Fri, 10 Sep 2010 11:38:30 +0100
"Recliner" wrote:
wrote in message

On Fri, 10 Sep 2010 08:53:12 +0100
Roland Perry wrote:
In message , at
20:05:28 on Thu, 9 Sep 2010,
remarked:

You would have thought the signal allowing trains out of the bay
platform would be interlocked to the points being set correctly
for the route over the crossover, wouldn't you?

Even in the presence of a fault condition (which they've apparently
admitted)?

So much for signals being failsafe. Failsafe unless the failsafe
fails. Which it obviously did.

Surely it was still failsafe? *No trains were signalled to collide
with each other.

Only because the oncoming train was still had 1km and some signals
between it and the station. If it had been 100 metres away we could
be looking at a very different situation.

Not as I understand it. After all, Tube trains routinely follow each
other all the time, just a few hundred meters apart. They are signalled
along the same route, but the signals also stop them occupying the same
sections. So in this case, even if the trains were on a collision
course, surely the signals (and train stops) would actually have stopped
them approaching each other too closely?

That is working in the same direction. At junctions where trains are
"head on", the signalling would act to stop a train clear of any
conflicting move if, for example a SPAD occured. A train on the wrong
line doesn't have this benefit. Boltar seems to know what he's talking
about.

Alan Ben It wrote:

Boltar seems to know what he's talking about.


They do say there's a first time for everything. ;-)

In message , at 10:42:51 on Fri, 10 Sep
2010, d remarked:
Surely it was still failsafe? No trains were signalled to collide with
each other.

Only because the oncoming train was still had 1km and some signals between it
and the station. If it had been 100 metres away we could be looking at a very
different situation.

Is that speculation, or have you done a site visit and examined the
configuration of the signalling?

While one train got sent off the "wrong way", I don't think anyone has
said that this was combined with route setting/signalling from the
*opposite* direction having ignored that this wrong thing had happened.
--
Roland Perry

On Sep 10, 11:38*am, "Recliner" wrote:
wrote in message



On Fri, 10 Sep 2010 08:53:12 +0100
Roland Perry wrote:
In message , at
20:05:28 on Thu, 9 Sep 2010, remarked:

You would have thought the signal allowing trains out of the bay
platform would be interlocked to the points being set correctly for
the route over the crossover, wouldn't you?

Even in the presence of a fault condition (which they've apparently
admitted)?

So much for signals being failsafe. Failsafe unless the failsafe
fails. Which it obviously did.

Surely it was still failsafe? *No trains were signalled to collide with
each other.

Yes they were. One train was on the line working in the wrong
direction. Would you drive the wrong way on a motorway?

"Alan Ben It" wrote in message

On Sep 10, 11:38 am, "Recliner" wrote:
wrote in message



On Fri, 10 Sep 2010 08:53:12 +0100
Roland Perry wrote:
In message , at
20:05:28 on Thu, 9 Sep 2010,
remarked:

You would have thought the signal allowing trains out of the bay
platform would be interlocked to the points being set correctly
for the route over the crossover, wouldn't you?

Even in the presence of a fault condition (which they've apparently
admitted)?

So much for signals being failsafe. Failsafe unless the failsafe
fails. Which it obviously did.

Surely it was still failsafe? No trains were signalled to collide
with each other.

Yes they were. One train was on the line working in the wrong
direction. Would you drive the wrong way on a motorway?

But would the signals have stayed green if the trains approached each
other closely enough to collide?