Re: "lost" trains

[pdwyer <pdwyerNOpdSPAM@ecn.net.au.invalid>]

> Stuart Ellis <mpp@zipworld.com.au> wrote in message
> news:3864ADD4.215A8EC4@zipworld.com.au...
> > I do believe that sand was a major factor, plus a few other
> things at the time.

In article <38709364@grissom>, "canetram59" <canetram59@hotmail.com>
wrote:

> I wouldn't have thought that any rust would have a chance to build
> up on a
> track as busy as Cowan Bank.
> canetram59

I've seen a railmotor disappear on a suburban line. Not much rust there
at all. The reason? Rail profile, or 'hollow wheels' as someone said.

The problem is, and is evidenced by the unbelieving trainspotters,
accidents are rarely caused by one outstanding feature.

Health and Safety people will tell you about this little pyramid which
starts with infractions, minor incidents and so on which lead to
accidents and fatalities.

In signalling, the object is to ensure distance separation of trains.
Accidents that occur must be investigated to see that the system has
operated according to its design, and that the design has not
contributed to the accident. Signalling has 'evolved' by accidents
finding loopholes in the system.

However, as the Cowan Bank shows, when your signalling system relies on
the correct operations of track circuits, you can find that sand is the
loophole, or rust. Rust can be dealt with, by the use of impulse track
circuits or stainless steel welds. Sand, however is harder to design
around.

Another thing people are rabbiting on about is what is occurring when
the signalling system is inoperable.

As I said before, signalling systems are designed to be fail safe. When
they fail, they restrict the movement of trains. An intermittent
failure can lead to a signal going back in the face of a driver or
'dancing'. The normal course is for drivers to report the incident for
further investigation by signalling staff.

However, when a signalling route has failed completely, the Rail
Operators must invoke procedures for the safe passage of trains. All
Rail Operators have these procedures, they've been around as long
signalling :-)

So people calling for trains to travel at 20 Km/h might find that
that's their rule :-)

You will find out if the procedures in NSW are sufficent after the
Glenbrook inquiry. What will probably be examined will be those
operating procedures, and whether they were strictly adhered to.

Unless you know the rules for each of the parties it is difficult to
offer a qualified opinion.



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