Re: English Railway Accident

[Bill Bolton <billbolton@computer.org>]

"KaMaK" <mckinnon@interact.net.au> wrote:

> I have always had deal doubts about the legitimacy of higher speed push pull
> trains - such configurations are quite common but defy safety logic. The
> survivability of 'loco first' crashes is much higher than for a light weight
> driving trailers where the mass is pushing from the rear.

I can't see push-pull is any different from an EMU or DMU, where the
majority of the propelling force is behind the leading vehicles, as
various "Southern Region" incidents over the years show.

> The chances of a 70t loco (XP) being lifted or pushed off the rails in any
> impact is significantly lower than a 30+t driving trailer.

There doesn't seem to be a great deal of evidence to support this if
you look at the published information of major causes of UK railway
accidents over the years.

> Generally the retardation capabilities of carriages are superior to locos

Really?  Why do you think this is so?

> so in an emergency brake application with a trailing loco the loco is going to
> continue to push down on the train making the probability of it remaining in
> line and upright significantly reduced.

The weight of the following coaches is enough to do this in any cases
unless the train is very short.

> The British experienced the risks of push-pull in Scotland about 20 years
> ago when a push-pull hit a cow and derailed at high speed with several
> deaths.

The issue is speed, not what's at the front of the train, even a small
irregularity or obstruction can derail a train when its a high speed.

The degree of devastation at Selby was caused by the front of the
passenger train hitting the front of the freight train when both
trains were still in forward motion.  A look at the diagrams on the
BBC web site showing where things endedd up is quite instructive.

It seems to me unlikely the outcome would have been much, if any
different, if the loco had been leading on the passenger train.

Cheers,

Bill


Bill Bolton
Sydney, Australia