I recall reading about turnarounds at the old (Wirral) Liverpool Central Low Level being a very slick operation utilizing crews waiting at the departure end of the platforms, and jumping on board as soon as the stock arrived.
Yes, it was indeed a slick bit of everyday working. I spent many moments in my younger years watching it on my way home, and there was a detailed thread about it here a while back.
It was designed and installed by Westinghouse in about 1905, with the conversion to electric operation, and the signal/point operation was completely automated. It lasted until around 1977 when the Loop Line replaced it. An island platform with a headshunt beyond, signals and points operated automatically and the rush hour turnround was 3 minutes from arrival to departure, with train frequency every 2.5 minutes. At moments there was a train each side of the island, with a third in the headshunt. The points were air-operated, and the HISS-BANG of them throwing was audible throughout the station.
The height of juvenile excitement was, inevitably, to slyly jump in on the arrival side after the porter had done the perfunctory throwing-out check, and ride into the headshunt and out again!