I have just got back from a fortnight in Fort William on the Jacobite support crew, am knackered!!!!
Anyway, while we where sat in Fort William allowing the punters onto the footplate the Caledonian sleeper service would arrive, at about 9:30am. I don't know when the stock returned, but it was still sat in the loop when we arrived back from Mallaig at 16:00.
It was an EWS 67 on the front, 67011 most of the time.
Here is a link for more info on it:
http://en.wikipedia.org/wiki/Caledonian_Sleeper#Route