IRSE Exam Forum

Is it required to lamp proving a GPL signal (Independent Shunt) if it is not having any signalled moments up to that signal?
Is it required to lamp prove route indicator for GPL?

(27-10-2016, 09:34 AM)mohansaikuppili Wrote: Is it required to lamp proving a GPL signal (Independent Shunt) if it is not having any signalled moments up to that signal?
Is it required to lamp prove route indicator for GPL?

To UK practice:
Not required
Not normally

(27-10-2016, 02:38 PM)PJW Wrote:

(27-10-2016, 09:34 AM)mohansaikuppili Wrote: Is it required to lamp proving a GPL signal (Independent Shunt) if it is not having any signalled moments up to that signal?
Is it required to lamp prove route indicator for GPL?

To UK practice:
Not required
Not normally

To expand slightly (again current UK practice):
There are some cases where it is required to prove a GPL such as where it is a LOS, but otherwise it is not a requirement - the case of having no signalled moves up to it is a good example. Never the less I would expect a full re-signalling scheme to provide lamp proving on all signals.

For route indicators associated with GPLs - no indication is required if the routes are all similar and none lead to a Limit of shunt or other hazard. If a Route Indication is provided, it must be proved for routes to a limit of shunt, but proving is not required where there is only one route or the routes are all similar and do not lead to a significant hazard.

Yes by necessity I was having to be brief and intended to go back to expand, but Dorothy beat me too it.
It does however depend on what you actuallly mean by "lamp proving"- whether it means "proved in the signal in rear" or merely indicated to the soignaller / alarmed to the technician.

I read the question specifically as applying to a GPL with no moves up to it, which rather rules out LOS or a GPL limiting moves on a running line not signalled further in that direction (which are the cases which are particularly worthy for proving).  I do find it rather ironic that current standards do require much more lamp proving than was done historically, given that the chances of an LED GPL being out are very small compared to the one ON lamp failing in a traditional GPL (used to be a very regular occurrence) and that there are nowadays typically far fewer shunting moves than used to be made on a layout.

Thank you very much Mr. Dorothy & PJW for the clarification.........
I got another doubt. Please clear it.
Incase the signal lamp proving is not required, how come the signaller knows about the indication?

(28-10-2016, 09:20 AM)mohansaikuppili Wrote: Thank you very much Mr. Dorothy & PJW for the clarification.........
I got another doubt. Please clear it.
Incase the signal lamp proving is not required, how come the signaller knows about the indication?

If the signal lamp is not proved at all (e.g. For SSI the lamp is not wired into a current proved input) then the signaller will only find out that it is not illluminated is if a driver, technician or some other trackside worker notices and reports it to them)