Re: John Brew (a blast from the past)

["Ben Staples" <BenKim@bigpond.com>]

Michael Edge wrote in message <35601BE3.24471D74@sia.net.au>...
>While his commentery is probably politically motivated, the origin of
>his sudden appearance is a report by Speno Rail Maintanace (contraced by
>the Rail Access Corporation to do regular reports on NSW metals). This
>was reported on p3 of todays (18/5/98) Sydney Morning Herald.
>
>Maybe the faults in question don't affect ride quality much, since in my
>experience (west of Clyde at least) the Western line is one of the
>better ones in Sydney (Clyde to Flemington is shocking).
>
>Without wanting to reproduce the entire SMH story, the Speno report
>detailed 62 locations that were Laser Spot Checked and found every one
>of those locations had one or more of the following faults: excessive
>curve wear, gauge corner damage and corrugation.
>
>Can anyone with experience in rail maintainance comment on the relative
>significance of these faults.  The story semms to be trying to suggest
>that a derailment is imminant and we all know how readily politicians
>and the media beat up stories for their own gain.


Curve rail wear is caused by the passage of wheels around a corner slowely
grinding away the head width of the rail. Why is this bad??? As the head
width decreases, the gauge between the two faces of rail increases. If the
wear gets to a certain point, then with some other factors, rail back
canting (tilting), rail fastener wear, a derailment can occur. With the
width of the wheels used in trains, rail wear alone will never cause a
derailment (Rail is condemned at a certain head width, and the road must be
closed when rail is condemned). Another problem is that the head wear moves
the point load of the wheel away from the centre of the rail web and places
a moment (turning force) on the web. This can lead to rail web failure.
Literally the rail bends over.

Corrugations in rail, from what I know, do not reduce the structural
properties of the rail. Ofcourse, just like a corrugated road, there is alot
more wear on equipment using the rail (rough ride), and the extra pounding
on the rail by vehicles going up and down increases rail defects.

I don't really know what they mean by gauge corner damage, but I suspect
they are talking about the running face of the rail pitting or having metal
gouged from the rail surface. I'll have to look this one up.


>Someone from the Rail Access Corporation was actually playing UP the
>significance of the report.  I suppose the state budget is just around
>the corner...


Ben Staples
Graduate Engineer
Railway Services Authority