At the heart of the Fell gearbox is a set of differential gears the same as you’d find in the axle of a car, and in the locomotive they are used to combine the output of more than one engine.
The six-axle goods locomotive in question – with 7500 kW the most powerful of the DLoco series ... In China, these components are assembled with other parts made by Dalian into the Voith SET-553 final ...