Even with diesel loco hauled, there was run round time at the least to add.
Did British Rail never use the practice from some other European countries of attaching the loco for the next journey on the back, uncoupling the previous loco, then pulling the carriages away and once clear, the now-light loco moves off to join the non-buffer end of its next train?
It depended a lot on what facilities were available at that point. For a reversal en route with no deport or crew based there, running round was almost inevitable. For example the last loco-hauled Cross-country trains reversing at Reading would do that, usually in P8/9 (as was). On the other hand, somewhere (and I can't recall where) I came across a timetable for steam-hauled District Railway trains reversing at Aldgate, and doing so quicker than you would do it today. Clearly that needs a replacement loco lurking at the end of the platform, and probably not following modern safety rules about multiple moving trains.
