Meaning it would have needed to be a Yorkshire crew route conducted by Carlisle to/from Dumfries? Unless the Yorkshire guys signed to Dumfries (can't think they would)? What time of day I wonder, because that would be a challenge especially first thing in the morning.
Interesting question. There was one Carlisle driver who had previously been at Skipton....but I'm fairly certain that he transferred back to Carlisle before the 150s arrived for their second stint in Yorkshire. When I was at Skipton, I took a 150 to Carlisle on at least two occasions....one of which was a Lancashire DalesRail service from Blackpool - coupled to a 156 - which I relieved at Hellifield and worked back Southwards in the afternoon.
IIRC, the only two S&C turns which had long enough breaks at Carlisle to traction conduct to Dumfries and back would have been on Saturdays. One was a Leeds job which worked the 08 47 from Leeds, arriving Carlisle at
11 28; returning with the semi-fast at 15 03, back into Leeds at about 17 30. The other was a Skipton job which relieved the 10 47 from Leeds at Skipton at 11 28, arriving Carlisle at 13 28; then returning from Carlisle at 16 18, arriving Skipton at 18 22.
However, you have to remember that a Leeds or Skipton crew traction conducting to Dumfries and back would still require a minimum 30 minutes break at Carlisle....plus 5 minutes walking time each way to and from the mess room on platform 1.