Re: Train Accident in Blue Mountains

["Dave Proctor" <daproc@sd5.mailbank.com>]

Bill Bolton wrote in message <248o4s8iog8goige7qjn2ebj8p1jiq0a6s@4ax.com>...
>"Dave Proctor" <daproc@spambait.umpires.com> wrote:
>
>> are no train stops. Train stops improve safety (if they don't, wy are
they
>> all ovewr Sydney and Melbourne)
>
>Trains stop will prevent certain types of accidents, specifically
>those related to inadevertant passing of signals at danger where
>traffic levels are high.  In that sense they enhance safety as far as
>accidents which might arise from SPAD events.
>
>They have no effect at all on other types of accidents, i.e.
>derailments, track obstructions, washaways etc etc and so do not
>"improve" safety for those types of accident.

And this was clearly either a SPAD or a faulty signal.

>> Having a level of safety that is less than what is possible makes it
unsafe.
>
><sigh>
>
>Centuries of saftey engineering practice says otherwise.

So you are saying that it is not the case that reducing the level of safety
from what is possible makes for an unsafe system? If a level of safety is
possible, anything less than that is unacceptable.

>> Tripping through a signal *might* have served to slow the train down
>
>If you are indeed as experienced with "tripping through" a syou cliam,
>you will know how it is done. If the driver has come to rest in front
>of the signal, the distance needed to trip through is perhaps 20
>metres and after the brakes have reset he is technically free to drive
>at whatever speed he wishes.

And your point?

>> particularly since the train had stopped at Glenbrook station, and would
>> have (presumably - notice, a presumption here) have received authority to
>> pass the signal before leaving the station. Tripping through the signal
>> *might* have meant that it would take extra time for the driver to reach
the
>> speed that the train was at at the time of collision
>
>The signal is 30 metres past the station.

So you made the point above that the train would travle about 20 metres.
Tripping through would have stopped the train 50 metres from the station.
Given the time for the brakes to reset, it is highly possible that the train
would have been going *much* slower when the driver saw the IP, and might
have been able to stop in time, since he would have been starting from 50m
closer to it.


>> - thus, the speed that the train was at when the driver spotted the I-P
>> would have been lower, and the impact *could* have been avoided or the
>> impact reduced.
>
>This is just silly.  You are building a "fairy castle" argument to
>support a position that clearly would have no bearing on the speed of
>the train at the point of the collision.

So let me get this straight. A train that trips through a signal 30 m from
the end of the platform, and travels 5 to 10 metres after tripping through,
therefore coming to a complete stand 35 to 40 metres from the end of the
platform, will be travelling at the same speed a few hundred metres further
down the track as a train that was constantly accelerating from the time it
left the platform. Yeah, right......

Dave