In the loft I have a Graham Farish N gauge Class 158 Alpha train.
I think this ran from Paignton and went via Salisbury to somewhere along the south coast. I wonder if it was a later extension of the Exeter-Brighton service?
Alpha Line was primarily the replacement of the irregular loco plus coaches services on the Wales and West network with hourly
DMU▸ trains designed for their regional (as opposed to local or suburban) use. The main service was Portsmouth - Cardiff and (I need to check) Cardiff via Hereford, Shrewsbury and Crewe to Manchester. Class 158 trains; perhaps a different thread for the rise of Alphaline and what has happened from then on?
In competition with
GWR▸ and Wales and West, South West Trains ran some Waterloo - Salisbury - Exeter trains on to Paington, Plymouth and Penzance. Those were not Alpha Line branded though they were class 158/159 operated, and I'm not aware of (but there may well have been) and through services from south east of Salisbury (i.e. via Southampton) to south west of Exeter (i.e. via Newton Abbot)
I certainly travelled on the Waterloo to Plymouth/Paignton. A 159 of nine coaches (3 units) left Waterloo, dropped three coaches at Salisbury, split at Exeter St David's with three coaches going to Plymouth and Paignton respectively. One Saturday because of engineering works the train was diverted via Southampton and was so late it terminated at Newton Abbot.