Re: Beresfield Accident Findings

[wallaby@fl.net.au]

In article <EsD8Gy.FIB@transdata.co.nz>#1/1,
  chris@transdata.co.nz (Chris Grace) wrote:
> I'm pretty sure that the trainstops used in NSW are the same ones used on
the
> London Underground, they are pretty standard Westinghouse gear.

They're apparently not quite the same.  I heard that the London train stops
don't have any proving contacts,  they are just assumed to be working.


> It has consistently been stated that the trainstops as used on LUL and parts
of
> NSW railways are not considered usable at high speeds (In this case so far
as I
> know 'high speed' means over around 35mph). Previous posters have described
> tripping when passing speed control trainstops at too high a speed, then
> resetting the trip once the train has stopped. If the train was moving too

I've seen trains trip at signals going over 100km/h.  When the naughty
apprentice gets a litle over zealous, waiting to work on the train stop and
pulls the pins before,  rather than after the train goes past it. :\


> The other problem is that trainstops are electro-pneumatic. This isn't a
problem
> in London as the signalling and points are (or were) also electropneumatic
and
> consequently air supplies were available to operate them. I don't know if
the
> City Underground in Sydney is all electropneumatic or not, but even if it
isn't

Pretty well all of Sydney City to North Sydney, Homebush and Wolli Creek are
EP.  There are EP train stops also at Hornsby and Campbelltown(or at least
there were in 1985).  Where they're not EP,  they're mostly Westinghouse JAH
style now,  which is electro-hydraulic.  Slighty longer train stop so they can
fit the hydraulic motor in.  They draw about 4Amps to drive clear from memory.


> we're talking about a pretty restricted geographical area, and in any case
> traction current could presumably be used to drive compressors. I
> could imagine problems getting compressed air to every signal in
> non-electrified or country areas.

Air is supplied from 415v compressors at various places.  Mostly 65psi,
except ESR which is 75psi.


>
> And, of course, trainstops are another maintenance problem. I have no idea
how
> they would fare in the open air in the country - they would obviously be
subject
> to vandalism, and unlike a signal, this wouldn't be immediately obvious to
> drivers, so they'd have to be inspected frequently.

They're about the least vandalised thing on the tracks actually.  And highly
reliable.  Maintenance frequencies in the UK are apparently something like 6
months,  here they are presently about 6 weeks,  but that period is getting
longer.



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