Re: Signaller causes SPAD

["Peter Dwyer" <peter.dwyer@qr.com.au>]

<antstig@my-deja.com> wrote in message 8q2fa7$dfq$1@nnrp1.deja.com">news:8q2fa7$dfq$1@nnrp1.deja.com...
> In article <8pmatk$5p51@inetbws1.citec.com.au>,
>   "Peter Dwyer" <peter.dwyer@qr.com.au> wrote:

> I can only speak for my company but in the vast majority of cases
> signals thrown (I prefer the word "thrown" to the cosy neutral
> "restored") back in the face of the driver are the signallers fault.
> Even they wouldn't have the nerve to concoct a story that the signal
> mysterioulsy went back on its own accord, of course that could happen
> as a signal is failing when a driver is approaching it thus causing him
> to hit it, but it is rare.

Hmm, well your company hasn't heard of relay interlockings then.

Signals in relay or electronic interlockings will restore if any of the
logic
used to clear the signal changes state.

That is, if there's a crossover in the route, and a train going in the other
direction breaks the detection, it will restore the signal for the other
driver.

If there's a faulty IRJ, which drops the track past the signal as he's
approaching
it, the signal will restore.

If any of the contacts in any of the logic circuit goes open circuit, the
signal
will restore.

Signallers in mechanical or panel interlockings do not restore signals as
easily as
controllers using mice, but it is more likely that the system will fail (in
large systems)
somewhere before a signaller will restore a signal (Real Life Experience).

Anyways, breath testing signallers is evident that your HR policies &
discipline
measures are shot. It's a cop out.

Seeya!