Supposedly an extra unit is required to run these Fishguard services. However, here's the best guess I've managed to come up with (with help from posters on the First Great Western Coffee Shop fourm) for the diagrams, which seem to suggest to me that no extra units are required at all.
Diagram 1 - Class 175
Current Work
05:43 Carmarthen - Pembroke Dock
07:09 Pembroke Dock - Manchester (dep. Carmarthen 08:30, arr. Swansea 09:23, dep. 09:55)
From September
05:50 Carmarthen - Fishguard
06:53 Fishguard - Clarbeston Road
07:33 Clarbeston Road - Fishguard
08:06 Fishguard - Manchester (dep. Carmarthen 09:00, Swansea 09:55)
Diagram 2 - Sprinter
Current Work
06:42 Cardiff Central - Carmarthen (coupled to another unit, which continues to Pembroke Dock)
09:00 Carmarthen - Swansea
10:05 Swansea - Pembroke Dock (dep. Carmarthen at 10:56)
Continues on Pembroke Dock work
From September
06:42 Cardiff Central - Carmarthen (coupled to another unit, which continues to Pembroke Dock)
08:50 Carmarthen - Fishguard
09:55 Fishguard - Carmarthen
10:56 Carmarthen - Pembroke Dock (picking up the present diagram)
Continues on Pembroke Dock work
Diagram 3 - Sprinter
Current Work
09:00 Shrewsbury - Llandrindod Wells - Swansea - Cardiff Central
15:14 Cardiff Central - Swansea (Swanline)
17:10 Swansea - Cardiff Central (Swanline)
Retire to Canton Depot
From September
09:00 Shrewsbury - Llandrindod Wells - Swansea - Cardiff Central
15:30 Cardiff Central - Fishguard (Swanline) (17:10 Swansea - Cardiff Central Swanline expected to be covered by extending WAG Express 2 to start from Swansea)
18:49 Fishguard - Whitland
19:38 Whitland - Fishguard
20:16 Fishguard - Carmarthen
I think these diagrams leave just two questions unanswered:
- Does having a Sprinter stabled at Carmarthen which presently wouldn't be mean an extra unit is required the next morning for peak strengthening of a Valleys diagram?
- What happens to the 1st Pembroke, which lost the Manchester train
Well, the Sprinter diagram that now ends it's day in Carmarthen has nowhere to go in the morning other than that 1st Pembroke service, so that's all the services running without extra units. That just leaves the question of whether morning peak strengthening of a Valleys service would be affected by leaving an extra unit at Carmarthen overnight rather than in Canton. Either way, can anyone see any mistakes I've made here, or would that work? If it does work, that Sprinter is left at Swansea at 09:23 after running the 1st Pembroke service. It could easily run an extra Swanline service to Canton, get refueled and then run fast back to Fishguard and plug the 5hr gap in the proposed timetable.