Running or facing Ground disk shunt signal operation

[Junctionmad]

Here's a question, I had always assumed that facing ground disks , ie those facing the running direction. , were ignored if the main running signal(s) elsewhere on the route were cleared. I have been told this is not the case and that any ground discs facing the train, would also have to be cleared before the main running signals should or could be cleared.

 

In single line working this would mean disks were pulled off for the passage of a train through the station ?..

[Junctionmad]

Here's a question, I had always assumed that facing ground disks , ie those facing the running direction. , were ignored if the main running signal(s) elsewhere on the route were cleared. I have been told this is not the case and that any ground discs facing the train, would also have to be cleared before the main running signals should or could be cleared.

 

In single line working this would mean disks were pulled off for the passage of a train through the station ?..

 

I've answered this myself and the issue is a divergence between UK and Ireland practice . In Ireland facing shunt signals remain On, while,main running signals are off. In the UK intermediate facing ground signals must be cleared ie off, if mail signals are to be cleared.

 

Interesting, the UK position is more logical. As a driver never process through a red light of any type. The Irish one is cheaper to implement !!

[Dhu Varren]

Interesting subject JM, something I had never considered before. It does seem though, that facing ground signals on running lines are avoided where possible, and any shunting moves in the running direction are controlled by subsidiary signals under the running signals, whether semaphore or colour light.

Interestingly, I have just watched the Belfast to Londonderry DVD, and there is only one instance of a facing ground signal on the whole journey, which controls entrance to the run round loop at Derry, and it is showing two white lights as the train approaches. NIR, of course would be subject to UK rules as opposed to Irish rules.

[jhb171achill]

Operational rules on NIR would actually be more in tune with the rest of Ireland, as railways in Ireland were in place over 90 years before the border was even thought of. UK practice is not dissimilar overall, of course, but the Irish railways standardised almost all practice years ago.

[Junctionmad]

Interesting subject JM, something I had never considered before. It does seem though, that facing ground signals on running lines are avoided where possible, and any shunting moves in the running direction are controlled by subsidiary signals under the running signals, whether semaphore or colour light.

Interestingly, I have just watched the Belfast to Londonderry DVD, and there is only one instance of a facing ground signal on the whole journey, which controls entrance to the run round loop at Derry, and it is showing two white lights as the train approaches. NIR, of course would be subject to UK rules as opposed to Irish rules.

 

Well in claremorris there are upwards of 5-6 facing disks depending on route setting and I no doubt think many complex single line stations would be similar.

 

The irish practice of ignoring ground disks , seems to stem from early pre grouping uk practice and may have been carried across at independence.

 

In later years post grouping in the uk , there is universal agreement that aside from a few unusual situations , facing discs would be cleared with main running signals to ensure drivers never passed a red light

 

( note this is all seperate to yellow discs )

 

I wonder what is the irish practice for colour light CTC. Controlled ground shunt signals , given the ease that they could be operated