Re: "lost" trains

["Notagunzel" <notagunzel@bigfoot.com>]

Stuart Ellis <mpp@zipworld.com.au> wrote in message
3864A820.F1161C2C@zipworld.com.au">news:3864A820.F1161C2C@zipworld.com.au...

> In regards to the disappearance of the light engine NR at Sydneham.   The
track
> circuit involved has two devices, conventional frequency track circuits
and DPU
> devices fitted, which is a small box fitted inside the running rail. It's
purpose
> is to pick up the wheel as it passes, due to the fact the DPU is basically
a coil
> of wire, and when the wheel passes (metal) it is supposed to create a
magnetic
> field and trigger the electronic device attached.

G'day,

This DPU device, does NSW use many of these?  I have to admit I'd never
heard of them used in NSW up to now, a similar sort of device was used on
certain Track Circuits in Victoria in the height of the Sprinter panic, but
AFAIK they were removed once the Sprinters got Track Circuit Assistors
fitted.  The Victorian Device (Track Shunt Device?) was a primary battery
powered metal proximity detector which dumped a short across the rails for x
seconds after a wheel passed them.

--
Mr Notagunzel.
Rail Transportation Connoisseur
notagunzel@bigfoot.com
(Regrets to announce there will be no further moves at
http://www.geocities.com/nota_gunzel
until further notice is issued from this office)