Re: Crossing loop design (r.e. Southern Aurora crash)

["Roderick Smith" <rodsmith@werple.net.au>]

I suspect that the reason for not providing catchpoints in high-speed
crossing loops is that the number of single-train significant accidents
which would ensue would give a total damage per time greater than the
number of head-on collisions which their use would prevent.  This is called
risk management in modern parlance.

NZ uses catchpoints on its short crossing loops on the Johnsonville line
(running into sand traps).  The speed is not so great.  This allows
simultaneous entry of two trains, and even the crossing of one overlength
train per peak.  The system works very well.
-- 
Regards
Roderick Smith
Rail News Victoria Editor

Craig Haber <albatross@harnessnet.com.au> wrote in article 
> In Victoria, at Lara and Laverton (and probably some other places), loop
> roads have 'slips' installed which are rodded to the points.  If the
> points are set for the main, the slip is open, train cannot exit loop
> road onto the main - it is derailed.  If the points are set for the
> loop, slip closes, train can safely exit loop road.
> It appeared on my travels that loops throughout NSW are set up the same,
> and talking to the train controllers at Junee suggested that this is
> indeed the standard set up.  He also suggested we were mad not to do so
> here.
> This begs the question - why is this not standard practice elsewhere?
> Didn't the Aurora go through no. 2 road?  Had Violet Town been equipped
> with an NSW (or Lara and Laverton) style loop, when the Aurora passed
> the stick with the road set for the main (and hence the slip open), it
> would been derailed - rather than proceding head on into the oncoming
> goods.
> Yes I concede there is the possiblity of something of a 'pile up' with a
> pass train being derailed at 115km/h, hence fouling the main line and
> being struck anyway, but wouldn't "some risk of collision" be preferable
> to "guaranteed collision"?  And given the push for driver only for long
> shifts on bigger and harder to stop freight trains, is it inevitable
> that more trains will overshoot loops and such collisions be more
> likely?