Re: Train Accident in Blue Mountains

[Dion Williams <onamission@start.com.au>]

Bill Bolton wrote:

> The IP was effectively still stopped on a downgrade, there would have
> been no "slack" in the couplings.

But neither was it at full tension. In any case it's not the couplings
that make the difference, it's the massive weight differential between
the trains. The tension in the couplings merely spread the force out
over a longer span, which doesn't mean a lot given the length and mass
of the IP compared to the IU. All I'm saying is that it appears from a
physics point of view that the impact speed was probably somewhere
between 20 and 50 km/h inclusive.
 
> > > Remember, not only did the driver have time to warn passengers, but
> > > another male passenger had time to start warning the upper deck
> > > passengers based on the drivers warning, so there were two sets of
> > > reaction times involved for the upper deck warning.  For this all to
> > > occur within 6 seconds would be a truly remarkable event.
> >
> > On the other hand it was a short enough period for the passengers in the
> > front middle deck area of the leading IU car to be unable to move from
> > their positions prior to the impact
> 
> How do you know that?  As far as I'm aware, they have been no reports
> as to the actual physical position of those passengers.

No but they were obviously still in the middle deck section at impact.

Dion