On 10 Nov 2004 09:09:38 -0800 someone who may be
(S.Byers) wrote this:-

1/ the rear power car, still under full power, caused much of the
crumpling and jack knifing, and

AFAIK it was not under full power.

Even if it was under full power the extra force that provided was
not enough to cause the damage. If it was then HSTs would be damaged
every time only the rear power car is working, which happens from
time to time. The forces the power cars produce are minor compared
to the forces involved in a crash.


--
David Hansen, Edinburgh | PGP email preferred-key number F566DA0E
I will always explain revoked keys, unless the UK government
prevents me by using the RIP Act 2000.

"David Hansen" wrote in message
news
Even if it was under full power the extra force that provided was
not enough to cause the damage. If it was then HSTs would be damaged
every time only the rear power car is working, which happens from
time to time. The forces the power cars produce are minor compared
to the forces involved in a crash.

Quite. The maximum tractive effort is about 8 tons, which I guess (I don't
have a power curve) would be only about a quarter of that at 100 mph.
Compared to the momentum of its 70-ton weight at 100 mph, plus that of the
other carriages at the rear, the effect of any power it could produce is
negligible.

Roger

Roger H. Bennett wrote:
"David Hansen" wrote in message
news
Even if it was under full power the extra force that provided was
not enough to cause the damage. If it was then HSTs would be damaged
every time only the rear power car is working, which happens from
time to time. The forces the power cars produce are minor compared
to the forces involved in a crash.

Quite. The maximum tractive effort is about 8 tons, which I guess (I
don't have a power curve) would be only about a quarter of that at
100 mph. Compared to the momentum of its 70-ton weight at 100 mph,
plus that of the other carriages at the rear, the effect of any power
it could produce is negligible.

Roger

Power was cut, full emergency brake was in and the power car at the rear
provided much additional braking effort to the rear five coaches, which
did not pile up onto the front three. The driver did everything right,
call it self preservation, instinct, skill whatever, it is a testament
to his last act and the construction of the train that so many survived.

In message , David Hansen
writes

Even if it was under full power the extra force that provided was not
enough to cause the damage. If it was then HSTs would be damaged every
time only the rear power car is working, which happens from time to
time. The forces the power cars produce are minor compared to the
forces involved in a crash.
I suspect the shape of the leading power car to have something to do
with gathering up the car instead of just shunting it to the side.
This is not a troll and unless you can add to the debate please don't
respond.
--
Clive.

On Wed, 10 Nov 2004 20:39:08 +0000 someone who may be Clive Coleman
wrote this:-

I suspect the shape of the leading power car to have something to do
with gathering up the car instead of just shunting it to the side.

As has been said before, the shape of the nose of the power car is
simply fibreglass. Behind that fibreglass is essentially what one
would find on the front of a locomotive, though without the buffers.


--
David Hansen, Edinburgh | PGP email preferred-key number F566DA0E
I will always explain revoked keys, unless the UK government
prevents me by using the RIP Act 2000.


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In article ,
David Hansen wrote:
On Wed, 10 Nov 2004 20:39:08 +0000 someone who may be Clive Coleman
wrote this:-

I suspect the shape of the leading power car to have something to do
with gathering up the car instead of just shunting it to the side.

As has been said before, the shape of the nose of the power car is
simply fibreglass. Behind that fibreglass is essentially what one
would find on the front of a locomotive, though without the buffers.


It does seem that most of the car wreckage was tossed aside very close to
the point of impact on the crossing. But I guess that something (the
engine perhaps ?) must have caught underneath and derailed the leading
wheelset.

David

On Wed, 10 Nov 2004 18:10:58 UTC, David Hansen
wrote:

: The forces the power cars produce are minor compared
: to the forces involved in a crash.

3000hp at 100mph is pretty close to 5 tons of thrust. As David says,
compared to the crash forces on half a train (4 * 35 ton coaches + 1 *
70 ton locomotive = 210 tons), that's trivial.

Ian

--

"Ian Johnston" wrote in message
...
3000hp at 100mph is pretty close to 5 tons of thrust. As David says,
compared to the crash forces on half a train (4 * 35 ton coaches + 1 *
70 ton locomotive = 210 tons), that's trivial.

Actually it's even more trivial than that, because the power car's engine
only produces 2250hp, of which (according to a general rule of thumb for
diesel locos) only about 80% would be available for traction even if not
providing ETS. So we are probably looking at 1600-1800hp available for
traction, depending on the ETS load, reducing the calculated thrust to
around 3 tons.

That's still higher than my guess yesterday (2 tons), but that was just a
guess which I thought afterwards might have been a bit on the low side.

Roger