Arbor lights lamp proving ?

[d7666]

Having waxed lyrical just now in a contemporary thread about a very technical subject I know something about, may I now pester the learned signals engineering people here about a somewhat simple point on conventional LU signalling ?

Am I right that LU does not lamp prove signals aspects (i.e. the reds the greens and the yellows) but does lamp prove the white lights ("arbor lights") in junction route indicators ? ISTR this information was transmitted to me in a classroom at Acton but unsure now, was a fair while ago, and not part of my day job to know this.

[Tom]

Most signal aspects are not lamp proved. Junction Indicators are, as well as red and some yellow aspects on the Metropolitan Line.

[class411]

What does 'Lamp prove' mean?

Is it some sort of feedback mechanism that tells the signalperson if the lamps fail?

[rincew1nd]

Yes.

"Lamp proving" is a part of the system that proves a signal to be lit before a train is allowed to approach it. If the lamp isn't proven as lit then the previous signal will be held at danger and there will be some kind of indication to the Signaller of why this is.

[Tom]

Dec 12, 2021 10:40:02 GMT rincew1nd said:

If the lamp isn't proven as lit then the previous signal will be held at danger and there will be some kind of indication to the Signaller of why this is.

On Network Rail there is generally a 'lamp failure' indication on the signaller's panel, though it's often one indication for several signals. London Underground doesn't do that, the failure is announced by other means - either by a track circuit failure in the case of a signal aspect or by the junction signal itself not clearing for the diverging route.

[d7666]

thanks

[Deleted]

You will get the junction lights lit but the signal stays at danger on LU anyways