Gearcase lube is a heavy STP like product, comes in a plastic bag that you just throw into the gearcase. The gears just grind up the plastic bag. The old tarry "crater" is not used by the Class 1 railroads I'm familiar with.

The Milwaukee Bi-polar electrics were not geared, but had the armature wound around the axle. They had only two field coils, verticle on each side of the armature-axle. Unlike the standard traction motor of today that has 4 field coils. This allowed the bi-polars axles to move vertically to accomodate roadbed iregularities. I have heard or read that these engines were very quiet and smooth pullers

Todays traction motors are attached to the axle with two bearings. Amtraks are roller bearing and have a failure senseing system, some locomotives are still friction. A flexable connection between the traction motor frame and the truck frame transmit torqe and allows for roadbed iregularities.