All my calculations have assumed that all of Stockport-Stoke is double track, with no passing places, and, indeed, there are no scheduled overtaking manoeuvres. Whether a stopper could be sidelined at Macc in order to be overtaken by a late-running express, I don't know, I haven't checked it out. I know there is a third platform at Macc, but it doesn't appear to get a great deal of use, other than in respect of terminating trains. Oddly, the third platform is not acknowledged on the National Rail station plan.