edwin_m
Veteran Member
I believe freights are "looped" on the middle tracks for passenger trains to overtake.Also on the GWR, Oxford had, and still has, platforms on loops with through lines, although very few if any regular passenger trains have not been booked to stop there.
Loops for stopping passenger trains aren't generally very helpful. Depending on signalling, the stopping train may have to wait 5min or more to ensure the non-stop gets a clear run through. That might have been acceptable in the days of steam but it doesn't really represent a good service today, and there are very few places where a stopping train is overtaken by a non-stop train in loops that are only just as long as the platform.
At Durham, and probably other places, the through line is basically there because the alignment of the platform would slow a non-stopping train down too much. Ely and Nottingham are examples where a platform that was formerly on a loop has been built out for trains to call on what used to be the through line.