In article , ] (Steve
Fitzgerald) wrote:

In message ,
writes

Tripcocks are present at all home signals on LUL lines.

You meant to say:

Tripcocks are present at all stop signals on LUL lines.

Didn't you?

Yes. I wondered whether I'd got it wrong when I wrote it. I meant to
exclude distant signals.

We don't have a concept of distant signals on LUL, only stop
signals and repeaters where sighting is restricted.

There are of course station starters (as far as I know at every
station but I'm sure someone will come along and tell me otherwise)
and approach signals to stations (known as outer, intermediate and
inner home signals). Long sections between stations are also split
up into sections with running signals (usually automatic). The key
point is that they are all stop signals (ie can show a red aspect)
and as such have an associated train stop. A repeater only being
able to show a green or yellow aspect does not have a train stop.

I think the point that has been made in this discussion (I've
avoided comments due to where I work) is that the train in question
was routed where it shouldn't have been but with normal signals
exiting the sidings and as such the driver would then have no
signals to observe (and thus no associated train stop to trip the
train). I can't disagree with the observation that the driver's
route knowledge should have told them that something was not right
and I believe from the initial RAIB report this is what happened
and the driver realised and stopped the train.

I look forward to seeing the full report if the RAIB to find out
what lessons can be learned for future safety.

Thanks for correcting my terminology, Steve. I was exactly meaning to
exclude repeaters which don't have train stops. Does that include fog
repeaters, BTW?

What seems to be rare on LU is three aspect signals. There used to be one
at the entrance to the Southbound platform at East Putney but that might
be BR practice.

--
Colin Rosenstiel

In message ,
writes

I look forward to seeing the full report if the RAIB to find out
what lessons can be learned for future safety.

Thanks for correcting my terminology, Steve. I was exactly meaning to
exclude repeaters which don't have train stops. Does that include fog
repeaters, BTW?

Yes it does. There are no fog repeaters with red aspects (after all,
they wouldn't be a repeater then would they?)

What seems to be rare on LU is three aspect signals. There used to be one
at the entrance to the Southbound platform at East Putney but that might
be BR practice.

On LU They are generally speed controlled signals and work in a subtly
different way although they are still stop signals and have a train
stop.

If they show green, there is a clear route set and no speed checking is
in place.

If they show red, speed checking is in place and the signal will show a
yellow aspect and the train stop will drop when the train's speed has
been proved below a set figure.

They are mainly used to protect reduced overlaps on signals to ensure a
train doesn't go thundering through an area with the potential risk of
collision.

All speed control signals seem to work in slightly different ways
depending on the local requirements and road learning includes these
nuances.

Of course where we share with BR then their signalling practices are in
force.
--
Steve Fitzgerald has now left the building.
You will find him in London's Docklands, E16, UK
(please use the reply to address for email)

"Steve Fitzgerald" ] wrote in message
...
In message ,
writes

There are of course station starters (as far as I know at every station
but I'm sure someone will come along and tell me otherwise)

Croxley...
--
Cheers, Steve.
Change jealous to sad to reply.

On Sep 10, 1:10*pm, "Richard J." wrote:
Recliner wrote on 10 September 2010
12:50:33 ...





"Alan Ben *wrote in message

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



On Fri, 10 Sep 2010 08:53:12 +0100
Roland *wrote:
In message5ZudnY273pDFGRTRnZ2dnUVZ7qSdn...@giganews. com, 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?

But after passing the wrongly-set points, the train departing from
Plaistow was travelling west on the eastbound track, and would not have
any signals to see. I'm not sure if it would have been back-tripped, but
the train that ran backwards downhill on the Northern some years ago
because the driver was asleep wasn't tripped for several stations IIRC.
--
Richard J.
(to email me, swap 'uk' and 'yon' in address)

Which is exactly why trains now have run back protection, which
applies the emergency brakes if the train runs more than six feet in
the reverse direction.

In article , ] (Steve
Fitzgerald) wrote:

In message ,
writes

What seems to be rare on LU is three aspect signals. There used to be
one at the entrance to the Southbound platform at East Putney but that
might be BR practice.

On LU They are generally speed controlled signals and work in a
subtly different way although they are still stop signals and have
a train stop.

If they show green, there is a clear route set and no speed
checking is in place.

If they show red, speed checking is in place and the signal will
show a yellow aspect and the train stop will drop when the train's
speed has been proved below a set figure.

They are mainly used to protect reduced overlaps on signals to
ensure a train doesn't go thundering through an area with the
potential risk of collision.

LU rules could have applied at East Putney then, with the speed control
for the approach to the junction at the platform ends.

All speed control signals seem to work in slightly different ways
depending on the local requirements and road learning includes
these nuances.

Of course where we share with BR then their signalling practices
are in force.

The example at East Putney was on non-shared track but I think has been
removed. It may have dated from the days when some trains non-stopped East
Putney.

--
Colin Rosenstiel

That's got Bob Crow written all over it. On the roads, speeding drivers
get sent on a Speed Awareness Course, but on the tube, it's the trains
themselves that get sent on the collision course.

In message
,
upinthesky writes

But after passing the wrongly-set points, the train departing from
Plaistow was travelling west on the eastbound track, and would not have
any signals to see. I'm not sure if it would have been back-tripped, but
the train that ran backwards downhill on the Northern some years ago
because the driver was asleep wasn't tripped for several stations IIRC.

Which is exactly why trains now have run back protection, which applies
the emergency brakes if the train runs more than six feet in the
reverse direction.

Except that the train in question would have been going in a forward
direction so everything you allude to is void.
--
Steve Fitzgerald has now left the building.
You will find him in London's Docklands, E16, UK
(please use the reply to address for email)

On 12 Sep, 23:46, Basil Jet wrote:
That's got Bob Crow written all over it. On the roads, speeding drivers
get sent on a Speed Awareness Course, but on the tube, it's the trains
themselves that get sent on the collision course.

I think I follow your play on words, but I don't follow the mention of
Bob Crow. Is it just one of those things that's randomly inserted
after a certain number of words?

[Yes, I only just saw this thread.]

In message , Steve Fitzgerald
] wrote:
What seems to be rare on LU is three aspect signals. There used to be one
at the entrance to the Southbound platform at East Putney but that might
be BR practice.

On LU They are generally speed controlled signals and work in a subtly
different way although they are still stop signals and have a train
stop.

If they show green, there is a clear route set and no speed checking is
in place.

If they show red, speed checking is in place and the signal will show a
yellow aspect and the train stop will drop when the train's speed has
been proved below a set figure.

I'm not sure if any still do, but they used to show red+yellow (with
train stop up) to show the train had entered the timing track circuit,
then change to plain yellow (with train stop down) after sufficient time
to ensure the train had slowed enough (if it hadn't, it would be tripped
before the signal could change).

Of course where we share with BR then their signalling practices are in
force.

Only when it's their track.

There *are* true LU three- and four-aspect signals on the Metropolitan
Line north of Harrow-on-the-Hill.

--
Clive D.W. Feather | Home:
Mobile: +44 7973 377646 | Web: http://www.davros.org
Please reply to the Reply-To address, which is:

In message , Steve Fitzgerald
] wrote:
Does 'stop signal' mean 'signal capable of telling a train to stop',
ie anything that can go red, as opposed to route indicators etc?

Basically yes. Of course a route indicator will always have a stop
signal with it

Not so.

On LU, if a signal with a route indicator has a repeater in rear, the
repeater has a route indicator as well. This even applies to fog
repeaters.

Even on the "big railway", there's the Preliminary Junction Indicator,
which doesn't have to be associated with *any* signal, let alone one
capable of showing red (that is, it can stand alone or be placed above a
distant signal).

--
Clive D.W. Feather | Home:
Mobile: +44 7973 377646 | Web: http://www.davros.org
Please reply to the Reply-To address, which is: