In article , (Mike
Bristow) wrote:

In article ,
wrote:
Well, the right answer would be for the railgrinder to have a
compatible braking system or a way of adapting it. No brakes is
inherently unsafe.

Or to have crew in position to re-enable a disabled braking system
while the train is in motion.

If they have no air and no power to get any, re-enabling will hardly help,
surely?

--
Colin Rosenstiel

"Tom Anderson" wrote in message
rth.li...
On Wed, 18 Aug 2010, martin wrote:

On Aug 13, 12:00 pm, Mizter T wrote:
On Aug 13, 11:23 am, Paul wrote:

Sounds like a serious screw up, thankfully no-one got hurt. RAIB will
of course be involved.

The RAIB have announced their investigation, with some preliminary
details and a picture of the unit involved:
http://www.raib.gov.uk/publications/...te_runaway.cfm

Thanks for that, i'm sure we all look forward to reading the report.

Something that I don't think had previously been released:

The crew of the grinding unit, who had no means of re-applying the
brake, jumped off the unit as it passed through Highgate station.

J. Jesus Krispy Kreme Christ on a Borisbike!

'no means of re-applying the brake' is a rather frightening phrase. I
would hope trains were not constructed in such a way that this could ever
be the case, but they are evidently not. Indeed, AIUI, air brakes work by
having a reservoir on each car that drives brake application when the
pressure in the brake pipe drops, but if there is no compressor in action,
as here, then this reservoir will be empty, and there will be no pressure
to apply the brakes even in the absence of brake pipe pressure. Seems like
a bit of a loophole in the fail-safety, but i'm not sure what else you can
do. Presumably a spring does not supply enough force to apply the brakes!

Why assume it even has a conventional railway air brake system. We're
talking about a large item of yellow plant brought in to the system that is
designed to work independently?

Reports earlier that it was an 'engineering train' and pictures of normal LU
battery locos aren't necessarily helping as far as I can see. It's just as
possible that it has never been designed to form part of a 'train' as
everyone is assuming...

Paul S

On Thu, 19 Aug 2010 04:24:05 -0500
wrote:
In article , (Mike
Bristow) wrote:

In article ,
wrote:
Well, the right answer would be for the railgrinder to have a
compatible braking system or a way of adapting it. No brakes is
inherently unsafe.

Or to have crew in position to re-enable a disabled braking system
while the train is in motion.

If they have no air and no power to get any, re-enabling will hardly help,
surely?

Surely it has some sort of handbrake? How else could it be parked safely
for long periods when the air will have all leaked out?

B2003

On 19 Aug, 10:24, wrote:
In article , (Roland

Perry) wrote:
In message , at 01:07:31 on
Thu, 19 Aug 2010, Stephen Furley remarked:

If there was no alternative to isolating the brake on the failed train
we don't know why another train, or locomotive, with a functioning
brake wasn't coupled behind it.

This seems to be the easiest to answer ... where would you find a
locomotive from, and how long would it take to get to the site with
(as appears to be the case) service trains in the way. The other
possibility would be to take the nearest train out of service, and
use that - although the decision was apparently made to pull using
a train from the north rather than push with one from the south.

Wouldn't there be a battery loco at Highgate Woods?

--
Colin Rosenstiel

Not likely, but that's to the north anyway. It would have to run
miles down the wrong line looking for a crossover.

On 19/08/10 10:48, d wrote:
On Thu, 19 Aug 2010 04:24:05 -0500
wrote:
In , (Mike
Bristow) wrote:

Surely it has some sort of handbrake? How else could it be parked safely
for long periods when the air will have all leaked out?

Perhaps it had a sprung parking brake, of the kind that automatically
engages when the pressure in the main reservoir is low? If it was
impossible to pressurise the air brake, such a parking brake would need
to be disabled...

-roy

On Thu, 19 Aug 2010 03:41:17 -0700 (PDT)
MIG wrote:
Not likely, but that's to the north anyway. It would have to run
miles down the wrong line looking for a crossover.

Of course if LU hadn't removed the crossover at Archway...

B2003

In article ,
(Paul Scott) wrote:

"Tom Anderson" wrote in message
rth.li...
On Wed, 18 Aug 2010, martin wrote:

On Aug 13, 12:00 pm, Mizter T wrote:
On Aug 13, 11:23 am, Paul wrote:

Sounds like a serious screw up, thankfully no-one got hurt. RAIB
will of course be involved.

The RAIB have announced their investigation, with some preliminary
details and a picture of the unit involved:


http://www.raib.gov.uk/publications/...gister/100813_
highgate_runaway.cfm

Thanks for that, i'm sure we all look forward to reading the report.

Something that I don't think had previously been released:

The crew of the grinding unit, who had no means of re-applying the
brake, jumped off the unit as it passed through Highgate station.

J. Jesus Krispy Kreme Christ on a Borisbike!

'no means of re-applying the brake' is a rather frightening phrase. I
would hope trains were not constructed in such a way that this could
ever be the case, but they are evidently not. Indeed, AIUI, air brakes
work by having a reservoir on each car that drives brake application
when the pressure in the brake pipe drops, but if there is no
compressor in action, as here, then this reservoir will be empty, and
there will be no pressure to apply the brakes even in the absence of
brake pipe pressure. Seems like a bit of a loophole in the
fail-safety, but i'm not sure what else you can do. Presumably a
spring does not supply enough force to apply the brakes!

Why assume it even has a conventional railway air brake system.
We're talking about a large item of yellow plant brought in to the
system that is designed to work independently?

Reports earlier that it was an 'engineering train' and pictures of
normal LU battery locos aren't necessarily helping as far as I can
see. It's just as possible that it has never been designed to form
part of a 'train' as everyone is assuming...

The RAIB site has a picture of the train.

--
Colin Rosenstiel

wrote in message
...
In article ,
(Paul Scott) wrote:

"Tom Anderson" wrote in message
rth.li...
On Wed, 18 Aug 2010, martin wrote:

On Aug 13, 12:00 pm, Mizter T wrote:
On Aug 13, 11:23 am, Paul wrote:

Sounds like a serious screw up, thankfully no-one got hurt. RAIB
will of course be involved.

The RAIB have announced their investigation, with some preliminary
details and a picture of the unit involved:


http://www.raib.gov.uk/publications/...gister/100813_
highgate_runaway.cfm

Thanks for that, i'm sure we all look forward to reading the report.

Something that I don't think had previously been released:

The crew of the grinding unit, who had no means of re-applying the
brake, jumped off the unit as it passed through Highgate station.

J. Jesus Krispy Kreme Christ on a Borisbike!

'no means of re-applying the brake' is a rather frightening phrase. I
would hope trains were not constructed in such a way that this could
ever be the case, but they are evidently not. Indeed, AIUI, air brakes
work by having a reservoir on each car that drives brake application
when the pressure in the brake pipe drops, but if there is no
compressor in action, as here, then this reservoir will be empty, and
there will be no pressure to apply the brakes even in the absence of
brake pipe pressure. Seems like a bit of a loophole in the
fail-safety, but i'm not sure what else you can do. Presumably a
spring does not supply enough force to apply the brakes!

Why assume it even has a conventional railway air brake system.
We're talking about a large item of yellow plant brought in to the
system that is designed to work independently?

Reports earlier that it was an 'engineering train' and pictures of
normal LU battery locos aren't necessarily helping as far as I can
see. It's just as possible that it has never been designed to form
part of a 'train' as everyone is assuming...

The RAIB site has a picture of the train.

Has that just been added today? I'm sure I didn't see it originally - but
(blown up) it doesn't look much like a normal railway coupling does it -
more like what you see on the back of a truck...

Paul S

In message , Paul Scott
writes

Has that just been added today? I'm sure I didn't see it originally -
but (blown up) it doesn't look much like a normal railway coupling does
it - more like what you see on the back of a truck...

The photo's too small to be sure, but it looks like one of TfL's three
Plasser machines, that are equipped with buckeye couplers - not the
standard Wedgelock couplers used on passenger stock, and nor does it
have conventional drawhooks for emergency use, like most of the
engineering stock.

--
Paul Terry

The latest piece in the Evening Standard has some more details from a
"leaked memo" - http://bit.ly/dufn0J

JP