One thing they could do is the following:
1tph - All stops
1tph - Semi-fast: Bellshill, Shotts, West Calder, Livingston South, Kirknewton, Curriehill, Slateford, Haymarket, Edinburgh.
1tph - Semi-fast: Uddingston, Shotts, West Calder, Livingston South, Curriehill, Wester Hailes, Kingsknowe...