Thanks for this well look at this 21:47 from Motherwell to Coatbridge Central then walking to Sunnyside and arriving Haymarket 23:04 verses 21:50 via Glasgow Central arriving 23:29. I also needed to be in Edinburgh at that time to catch the last Fife circle train. Out of interest why is there is no direct at night from Motherwell to Edinburgh!?
When it comes to ScotRail a main factor will be the drivers that do this route via both Carstairs and via Shotts to and via Motherwell are based at Motherwell and I believe it’s only one link - and probably the seniority link that are passed for these routes.
The Conductors that cover these two routes- again Via/to/from Motherwell to Edinburgh via Carstairs or Shotts are based at Glasgow Central.
No Edinburgh drivers or conductors are passed for via Motherwell and Carstairs. They are passed for Glasgow Central to Edinburgh via Shotts end to end only.
You could do it Motherwell to Bellshill and change there onto a via Shotts service to Edinburgh, but the problem is the evening service thins out dramatically in the evening on this route and i’m not sure if it’s a valid routing either.