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

[Tony Gatt <baulko@tig.com.au>]

BJ wrote:

> Mark is correct regarding the suggestion that what you saw were sidings.
> Devices such as slips, derails and scotch blocks are primarily designed to
> prevent runaway vehicles departing a siding and heading for the mainline
> after brake failure or similar. You may notice that the derailing device is
> always on the side furthest from the main line where possible to prevent a
> collision of a derailed runaway with a scheduled train.

How does this work at Sydney Central, where the derails are off the centre road
and either side are platform roads. (Plats 1 & 2 at Central, as well as 3&4).

The centre roads will hit a train either way, I wonder what method they used to
decide which one would do the least damage?

> Installation of these devices on crossing loops (which are classified as
> mainlines) really adds as many problems as it solves, (e.g. detection of
> slips being closed, etc.) especially as they are really meant for slow
> moving vehicles - not really applicable to situations like Violet Town etc.

but if the catch blade was on the straight rail, once the blade is closed, it
would permit reasonable speeds for the exit of the train. The design of the
catch blade is predominalty half a set of points, and with no "frog" to bounce
the train around on, loop speeds could more than likely still be obtained.

They use it in Sydney, theres no reason why it wouldn't work in Melbourne.

> Regards, BJ

--
Thanks, Tony.

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