Derailment at King's Cross

Ian G Batten said:

> > "On this tragic day, our deepest sympathies lie with the Jarvis
> > shareholders..."
>
> Quite. However, it's going to hole Jarvis' case over Potters
> Bar below the waterline, so it's a big news story.

Are the two connected?

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Chris Game <chrisgame@!yahoo!dotcodotuk>
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Chris Game wrote:
> Ian G Batten said:
>
>>> "On this tragic day, our deepest sympathies lie with the
>>> Jarvis shareholders..."
>>
>> Quite. However, it's going to hole Jarvis' case over
>> Potters Bar below the waterline, so it's a big news story.
>
> Are the two connected?

Only by a fairly lengthy diversionary route.

Clive D. W. Feather wrote:
> In article <VGeXi0KRWsZ$EwO1@romana.davros.org>, I wrote:
>
>> There has been a minor derailment at King's Cross this morning.
>
> [...]
>
> This morning there were trains trapped in platforms 1 and 5, as well as
> the derailed train and the 373 in platform 6.
>
> Writing at 14:30 (as the 14:21 to PBO pulls out), these trains are all
> still there. There is blue fencing separating the A/B/1-6 side of the
> throat from the C/D/7-11 side.
>
>> 91104 is stopped immediately outside Gasworks Tunnel. As best I can see,
>> it was leaving platform 4 (the rear of the train is just beyond the
>> footbridge) when the rear bogie of the first carriage derailed.
>
>
> Now that I got a closer look as we pulled out:
> - the front bogie of the loco is inside K2027 points (see diagram in
> other post) but, I think, on the rails;
> - the rear bogie and the front bogie of the first carriage are derailed;
> - the rear bogie of that carriage has one pair off and one pair on the
> rails.
>
>> Platforms 1 to 6 are completely out of use, as are A and B roads through
>> Gasworks Tunnel and, therefore, both fast roads south of Holloway. The
>> station is having to work through one pair of tracks and only 5 of the
>> 11 platforms (and GNER can only use 2 of those).
>
>
> And, I forgot to add, of those two, one of them (platform 7) can only be
> reached over C road.
>
>> My *guess* for the location of the derailed axle is the diamond labelled
>> 6/4,
>
>
> That's the route that the train was taking. To be precise:
> 2024B reversed (slip points set for non-slip)
> 2024C reversed (switch diamonds set for diagonal movement)
> 2025A reversed (switch diamonds set for diagonal movement)
> 2025B reversed (slip points set for non-slip)
> 2026B normal (slip points set for slip)
> 2024F reversed (slip points set for slip)
> 2027D normal (tunnel mouth points set for 4-9, not 1-5)
> 2019 normal (tunnel mouth points set for 1-6, not 7-9)
>
> The derailment must have been at 2026B or 2024F. Without a photo of the
> scene I can't do better.
>

Clive,

From the photo on the BBC site it looks as though the train has been
routed through the switch diamonds (the '6/4' set, on the diagram in
your other post) set 'obtuse' (i.e the route you would use the slip
connection for), this fits with the driver apparently spotting the
problem and trying to stop. Channel 4 news has just mentioned that
(paraphrasing) "part of the points was left out, presumably until
'later', and the engineers should have disconnected the signalling so
that the train could not be sent on that route".

Now, there doesn't appear to be anything missing, and there is the
reference on the BBC site to failing to 'reset' the points, so it
could be that the switch diamonds were clipped 'out of use' in the
position in which the train took them, when the usual procedure would
be to disconnect the relevant route(s) in the interlocking. However,
even if this were not done, the detection would not have been correct
for the route called, and a proceed aspect should not have been
possible. Curious.


Wobbly Bob

"Wobbly Bob" <never.read@> wrote in message
news:3F677CF1.40200@...
>
> IANAPWE

Brilliant!!!

Ian G Batten said:

> In article <MPG.19d1562730d91432989771@news.CIS.DFN.DE>,
> Chris Game <chrisgame@example.net> wrote:
> > Ian G Batten said:
> >
> > > > "On this tragic day, our deepest sympathies lie with the Jarvis
> > > > shareholders..."
> > >
> > > Quite. However, it's going to hole Jarvis' case over Potters
> > > Bar below the waterline, so it's a big news story.
> >
> > Are the two connected?
>
> If you're claiming that it can't have been you because your processes
> are sound, later problems rather undermine it.

If you're claiming that because J. were responsible for KC it must be
responsible for PB, that's like saying because someone was a thief
once, they must have taken every missing purse!

--
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Chris Game <chrisgame@!yahoo!dotcodotuk>
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In article <MPG.19d1a262ac1cca6c989772@news.CIS.DFN.DE>,
Chris Game <chrisgame@example.net> wrote:
> If you're claiming that because J. were responsible for KC it must be
> responsible for PB, that's like saying because someone was a thief
> once, they must have taken every missing purse!

I'm not saying that. Jarvis claim, amongst other things, that they have
a good quality system which means that the errors that some accuse them
of at Potters Bar couldn't have happened. Here's a case, under the same
quality regime, where the processes have failed. Correcting your
analogy, that's like saying because someone left their door open on
Tuesday, their claim to have been burgled by someone able to unlock
their front door on Monday is weakened.

ian

Clive D. W. Feather wrote:
> In article <3F6A34B3.5030004@>, Wobbly Bob
> <never.read@> writes
>
>> I have heard two explanations today, one mentioned "crossing", which
>> in a diamond/slip there are only two of, common crossings at each end.
>> The obtuse crossings associated with a 'fixed' slip are replaced by
>> the switch diamonds. The other said "wing rail", which could relate
>> to the angled stock rail portion of the switch diamonds,
>
>
> But it shouldn't be running on those bits of rail. I assumed it referred
> to the curved rail between the two straight rails; in this case (a train
> curving right) the left-hand rail between the point where the wheel
> crosses the right-hand rail from platform 5 and where it crosses the
> right-hand rail of the diagonal route to road C.
>
The angled rail is part of the running surface as it forms the stock
rail for the switch diamond.

If I understand your description of the "curved rail", referring to
your earlier diagram, this forms a double ended switch, and is
'paired' with the outermost 'stock' rail. As I have said elsewhere,
removing only one of the switches is not usual IMX, but it sounds as
though this is a common practice in this neck of the woods, as from
your post on the OOU crossover at Holloway it seems the same has been
done there.

The old DoT "Requirements" book required, for facing points in
passenger lines, "not less than two stretchers..." and "a third
stretcher locked by the FPL" - may not be the exact wording, but the
gist is there. Removing one of the switches effectively destroys the
"stretcher" function so, technically, the points fail the requirements
on both the above counts.

Also, removing the open switch takes away the point of attachment of
one of the detector rods. Leaving this lying on the floor is likely
to result in it moving out of position and failing the detection, so
you either have to fix it somehow, or strap out the detection in the
machine or the loc. Doing the latter whilst you still have a switch
present (albeit clipped) is asking for trouble, especially in vandal
areas. I have never seen points, still being run over, partially
dismantled in this manner, and I seriously doubt it would be accepted
in our area.


>> Both of the explanations are tending to this being similar to the
>> Aldwarke incident, which you suggested earlier.
>
>
> Not me, but I agree.
>
You're right, it was David H. Sorry about that (and to David as well).

>> When I last had involvement with this type of work,
>
> [...]
>
> Interesting. Thanks.
>
>> Information I have received today suggest that KX was done under SMTH
>> (Maintenance), which the outcome suggests may not have been
>> appropriate. This procedure is intended to cover renewal/replacement
>> of minor items (eg cable, signal head, point machine etc.) with an
>> identical item, or at least one that is 'operationally equivalent'.
>
>
> Even that can be risky. I am reminded of the Farley Junction collision.
> There a transformer/rectifier was being installed as a like-for-like
> replacement. Unfortunately, it wasn't the same design and had to be
> installed on the floor of the location cabinet instead of shelf where
> the last one was, and wires run from it to the terminals. The
> technicians crossed the wires.
>
> Normally this wouldn't matter, but unfortunately the facing crossover at
> the junction used polar relays in the loc cab for both points drive and
> points detection. So the box was calling the points normal, the loc
> cabinet commanded them reversed, they reversed, detected reversed, and
> the loc cab reported normal detection to Leeds box, allowing the route
> to clear with the expected fatal results.
>

SMTH procedures, properly applied, would have shown up the error, but
such procedures did not exist at the time, it was left to the tech's
knowledge, experience, and common sense to put back what was taken
out. I've been involved in similar failures myself, this regrettable
incident, in which (IIRC) both drivers died, serves as a warning that
even the simplest job can have grave consequences if not carried out
diligently.

Another contributary fact was that the busbar fed both ways as the
'cut section' wasn't to electrification standards. If it had been,
there would have been separate supplies (eg B50(N) & B50(S)), so with
only one of them the wrong way round, either the control OR the
detection would be crossed, but not both, so the error would have
shown up.


Wobbly Bob

"Wobbly Bob" <never.read@> wrote in message
news:3F6CB1A9.9050005@...

Are you ex-ScR (just guessing :-) ? Never got North
> of Gretna myself !
>
> Wobbly Bob

Correct...ex BR/Scotrail/BRIS/Railtrack/Halcrow, now Los Angeles MTA. Can't
accuse me of staying in the one place too long :-)