Re: Indian Pacific Crash

[John Duncan McCallum <mccallum@melbpc.org.au>]

Notagunzel wrote:

> > > In article <7qfcbv$2ktn$1@otis.netspace.net.au> "Exnarc"
> > <gwrly@netspace.net.au> writes:
 
> > > >Source has reported that IP prang was caused by crew member on ground
> > > >opening switch in path of IP, diverting it onto the goods.

> > > >Route was set correctly but he was standing alongside the switch stand
> > and read the wrong face, in a panic without looking at the blades he
> though the points.

Much snipped


> > Switch Stands, aren't all mainline points on the TAR fitted with them?

> >  As for the crew member being at the points, the old rules for CR T.O.
> > working required that a member of the other crew admit the second train to
> > the cross by showing a green flag or light from the points, not sure how
> > they do it, now that radio has become the main form of safeworking in TO
> > Territory.
 
more snipped

> I have got a small piece (including pictures) on the TAR loops on my site:
> http://www.geocities.com/CapeCanaveral/Cockpit/9412/tar_loop.html

> Just to summarise, the points between the main & loop are power operated by
> dual control point machines, the points also are fitted with switchstand
> indicators, and the position of the points are also repeated by
> searchlights mounted on the roof of the equipment hut.
 
> The points are self restoring, and to provide the logic to state when the
> train has passed over the points, there is a crude system resembling an
> axle counter.  This uses commercial proximity detectors & a PLC to count
> the axles.  BUT...  this 'section' is only between the fouling point of the
> loop, and the toe of the turnout, so if the poor soul pushed the reverse
> button just as the train approached, the points would have motored across
> in front of the IP, admitting it into the loop, and on to the goods.  There
> is therefore, AFAIK, no approach locking.
 
> Doesn't seem very safe, does it?  ARTC must be thinking along similar
> lines, as Westinghouse has got a contract for the resignalling of all the
> loops, AFAIK the latest edition of Track & Signal has details.  However, at
> this point, I'm only aware of Tent Hill, the first loop out of Port Augusta
> having being completed.  (They may have done more now, but I haven't heard
> anything.)

To my knowledge, the above arrangement is/was only installed at loops
between
Port Augusta and Tarcoola. West of the latter location, all loops were
fully
manual.


John McCallum