rather than a true hydraulic transmission in locomotive where the engine
drives a hydraulic pump which sends high pressure oil to turbines attached
to wheels - ie with no mechnical connection between engine and wheels.

None do this - choice between a powershifting conventional type gearbox as
in the Hymek, or multiple torque converters filled and unfilled with oil as
fitted to Westerns

Epicyclics only used with small engines.

Sprinter things AFAIK use choice of torque converter then lock up top.

Aghh electric transmission is easy in comparison only field diverts to worry
about.