Thankyou . And presumably vice versa - the loco that did the ECS into Glasgow central then trundles over to Edinburgh to take the Highlander south?
It does indeed, usually running as 0C16 2342 Glasgow Central to Edinburgh.
For example, last night:
https://www.realtimetrains.co.uk/service/gb-nr:C04522/2026-09-14/detailed
The exception tends to be when the Fort William lounge plus seated coach require rotating through Polmadie, at which point the loco in question returns to Polmadie and takes the new coaches across to Edinburgh before working the southbound Highlander, with the northbound Highlander 92 taking the two old coaches back to Polmadie before running to Glasgow Central light to retrieve the northbound Glasgow ECS.
The southbound Edinburgh Lowlander portion 92 usually spends the night at Carstairs before working the northbound Edinburgh Lowlander.
Sum total of 6 92s used most nights.
Now you mention it, wasn't there a problem last week when an early morning Avanti had to be cancelled because the platfom it would have used at Glasgow was still occupied by the sleeper stock, waiting for the loco to release it to come across from Edinburgh, the loco having been delayed whilst working the northbound Highlander?
Yes - Twice last week the ECS was late out of Glasgow because the locomotive was held up with the Highlander. One of those days resulted in a Pendo running ECS, might have been as far as Preston.