For the random off peak ones Ive just looked up on RTT the difference is 10 minutes, so 2 minutes per stop, which is about right for units, and going into SHF there's 4 mins of allowances, as you say.The service I use quite a lot from Retford to Sheffield has an enhanced service as part of the new timetable. I can't believe that the service that now only stops at Worksop before Sheffield is only 8 minutes quicker than the stopper that calls at 5 extra stops. Any thoughts as to why this is so slow, I know there's slack timetabling as the existing service quite often arrives early outside Sheffield and then sits in the tunnels for 5 minutes or so.
I notice that pass-to-pass averages are just under 60mph - is the line limit higher?