RGIs and Points

[Deleted]

If a sectionalised gap happens to coincide with a facing junction, will the RGI's illumination circuit be linked with the point detection mechanism?

Case in point: Green Park Junction. If the traction current is off on the road to Charing Cross and the facing points are returned to normal, will the RGI illuminate?

[Tom]

Yes, RGI's reading over points are conditioned by which way the points are lying.

[Deleted]

How does that work? I have read stuff in the past which states that RGIs are activated by stonking great big relays with full traction voltage across some of their contacts; is there an additional connection via the point detection mechanism?

[Tom]

The current on the rails is used to operate the current on line relays, which are of various vintages. The COL R contacts are used in 100v signalling circuits to operate COL PR's which are repeaters. The COL PR contacts are the ones used in the RGI circuits themselves.

And contrary to popular opinion, COL R contacts aren't that massive.

[Deleted]

Interesting. What does that setup look like?

Connecting the actual RGI unit via two sets of relays sounds somewhat inefficient - is it an add-on to something else that can share part of the circuit?

[Deleted]

there is a box called a N16 box which some have 6 or 4 contacts in them this is connected to the switch which is usally reverse if there is a RGI involved then this contact is in the indication of the points so if you get a reverse indication the RGI will lit up

[Deleted]

They usually get reported for having no illumination by some idiot too.

[Colin]

tom said:

Yes, RGI's reading over points are conditioned by which way the points are lying.

Interesting....................

Take another example - Earls Court.

Say the current goes off on the Earls Court - Putney Bridge section. That will cause the Rail Gap Indicators (RGI's) to illuminate on both platforms 3 & 4. But trains can still run towards Olympia / West Kensington (obviously following clarification of which traction current section the RGI's are showing for).

[Deleted]

colin said:

Take another example - Earls Court.

Say the current goes off on the Earls Court - Putney Bridge section. That will cause the Rail Gap Indicators (RGI's) to illuminate on both platforms 3 & 4. But trains can still run towards Olympia / West Kensington (obviously following clarification of which traction current section the RGI's are showing for).

If thats the case, you shouldnt pass it, because the WRM states that a RGI should not be passed if it is illuminated

[Colin]

Well that's most of the District line drivers up on a DB then!

It may be a 'local' thing - but those RGI's will illuminate for either the Earls Court - Putney Bridge section or the Earls Court - Barons Court section. Signals can be cleared for the opposite route (and maybe even the route that the RGI's apply to ), so providing we assertain which route has no traction current and we have the signal for the opposite, we can continue. Whilst I've not personally been in that situation as a driver, I did observe it many times whilst on the station side.

Also, illumiated RGI's can be passed on the authority of the line controller if they are faulty.

[c5]

Also say a RGI indicator is provided at a station - and illuminated. The Service Controller can authorise a Train Operator to pass it if the route the train is going to does have traction current.

If the RGI is illuminated because of a defect and the Controller confirms with the Power Control Room that the section is live. The RGI can be "bagged over" or have a fuse removed - but Power Control must be advised that if Traction Current for that section is discharged so must the section in the rear.