Thanks everyone, will update as soon as I can get to my computer
Just noted this is “UK Rail Forums” yet we are missing an entire part of the UK here so here we go!
NIR have driver depots at Derry, Coleraine, Larne Harbour, Bangor, York Road, Adelaide and Portadown.
Funnily enough, I was talking to an NIR driver on Facebook only a few weeks ago. He explained the situation as thus:
Everyone signs the triangle of Larne - Bangor - Lisburn.
All depots except Derry & Coleraine add Lisburn - Portadown (the two Northwest depots seemingly used to go to Portadown as well but no longer have any booked work).
The Belfast depots, Derry and Coleraine add Belfast - Derry / Portrush.
The Belfast depots and Portadown add Portadown down to Dublin Connolly.
Everyone signs the CAF 3000 & 4000 DMUs, and the depots that go to Dublin also sign the Enterprise stock and 201 locos.
If you can confirm the above or amend as necessary I'll be happy to add them in?
(And before anyone points it out, readers may feel free to read "Derry" as "Londonderry" if it makes them feel better).