On Thu, 13 Oct 2005 08:47:54 GMT, "Richard J."
wrote:

Paul Terry wrote:
In message , Brian Watson
writes

Just heard on BBC London this morning that service is still
suspended.

:-(

According to TfL this is now due to signalling problems affecting
the entire Northern line.

LU have been blaming the tripcock problem on the "signalling system"
from the start.

Another question: what, if any, differences are there between the
tripcock systems on the 1995 (Northern) and 1996 (Jubilee) trains, which
are generally of similar design from the same manufacturer?


I think it has to do with the company that maintain the Northern Line
stock, who are different from Jubilee Line stock maintainers.

Life without sex just isn't life.
Make love not war!

Just rumour, though,
at present.


Oooh, we all love a bit of rumour;-)

Excuse my ignorance, but why in the 21st Century are saftey-critical
devices on one of the most heavily-used urban metro systems in the
World reliant on a bit of string?

Neill

On 13 Oct 2005 06:16:55 -0700, "Neillw001"
wrote:

Excuse my ignorance, but why in the 21st Century are saftey-critical
devices on one of the most heavily-used urban metro systems in the
World reliant on a bit of string?

What would you prefer? A switch, a relay, an actuator and a bit of
wire? Why be complicated if a simple mechanism works?

In article , Laurence Payne wrote:

Excuse my ignorance, but why in the 21st Century are saftey-critical
devices on one of the most heavily-used urban metro systems in the
World reliant on a bit of string?

What would you prefer? A switch, a relay, an actuator and a bit of
wire?

Right now? Yes.

Brian
--
* * * * ** * * ** ** * *
* ** * * ** * * * *
* * * * * *

R.C. Payne wrote:
Richard J. wrote:
Paul Terry wrote:

In message , Brian Watson
writes


Just heard on BBC London this morning that service is still
suspended.

:-(

According to TfL this is now due to signalling problems affecting
the entire Northern line.


LU have been blaming the tripcock problem on the "signalling
system" from the start.

You seem to be implying this is in accurate.

Primarily I was correcting the misleading impression given by the word
"now".

I would say that the tripcock system is part of the signalling
system just as much as any set of lights, cables or signalboxes
(or whatever LU call them). Just because this part of the system
is train and not track mounted, doesn't make it any less part of
the signalling system.

I can almost agree with that. However, LU are now saying that the
suspension is in force "while work to modify safety equipment on
Northern line trains is carried out", which is much clearer.
--
Richard J.
(to e-mail me, swap uk and yon in address)

Neillw001 wrote:
Excuse my ignorance, but why in the 21st Century are saftey-critical
devices on one of the most heavily-used urban metro systems in the
World reliant on a bit of string?

If there was indeed a "bit of string" instead of a great thick rope, we
probably wouldn't have the current problem. We'd just have bits of
string breaking occasionally when drivers tried to reset the tripcock,
but that wouldn't affect safety.

--
Richard J.
(to e-mail me, swap uk and yon in address)

It's not a piece of string, it's quite a substantial piece of rope, which
adds to the resetting difficulty. The trains were originally part of a super
line upgrade so the tripcock reset cord was installed as a temporary measure
until ATP/ATO was introduced.
The cord itself goes through several tight bends from the loop that the
driver pulls in the offside cabinet down to the trip itself. The bends and
cord thickness have been a problem since we first tested train set 1 on the
test track at Washwood Heath.

Whilst conducting the conversion training for the drivers we used to tell
them to stick their J Door Key through the loop to get better leverage and
failing that, get out of the cab and attempt a reset pulling where the cord
is visible (about 6 inches from the trip).


"Neillw001" wrote in message
oups.com...
Excuse my ignorance, but why in the 21st Century are saftey-critical
devices on one of the most heavily-used urban metro systems in the
World reliant on a bit of string?

Neill

"Christine" wrote in message
news
On Thu, 13 Oct 2005 08:47:54 GMT, "Richard J."
wrote:

Paul Terry wrote:
In message , Brian Watson
writes

Just heard on BBC London this morning that service is still
suspended.

:-(

According to TfL this is now due to signalling problems affecting
the entire Northern line.

LU have been blaming the tripcock problem on the "signalling system"
from the start.

Another question: what, if any, differences are there between the
tripcock systems on the 1995 (Northern) and 1996 (Jubilee) trains, which
are generally of similar design from the same manufacturer?


I think it has to do with the company that maintain the Northern Line
stock, who are different from Jubilee Line stock maintainers.

Life without sex just isn't life.
Make love not war!
They are both maintained by (Tubelines) Alstrom. The diffrence is that ILRC
is the Northen line was a Alstrom design and build and the Jubliee line was
a LU design and Alstrom build. Therefore despite them only being a year
diffrent in age 95 Nor 96 Jub there are signifcant diffrences.

In article ,
(Bob Rodden) wrote:

It's not a piece of string, it's quite a substantial piece of rope,
which adds to the resetting difficulty. The trains were originally
part of a super line upgrade so the tripcock reset cord was installed
as a temporary measure until ATP/ATO was introduced.

The cord itself goes through several tight bends from the loop that the
driver pulls in the offside cabinet down to the trip itself. The bends
and cord thickness have been a problem since we first tested train set
1 on the test track at Washwood Heath.

That would explain the old-fashioned trip cock technology but not the
complexity of the rope arrangement. Ropes have been routed outside in
the past in modification programmes.

Whilst conducting the conversion training for the drivers we used to
tell them to stick their J Door Key through the loop to get better
leverage and failing that, get out of the cab and attempt a reset
pulling where the cord is visible (about 6 inches from the trip).

But why is the contemporary 96TS not subject to the same problems? It's
actually older as the 95TS came into service after the 96.

--
Colin Rosenstiel