What Is A Western?

How a Western works

All Western Class 52 locomotives were fitted with two engines driving two transmissions. The equipment associated with these was duplicated in each end.

When running the Maybach MD655 engine (13) rotates the Engine to Transmission cardan shaft coupled to the transmission. Using internal gears, two smaller cardan shafts mounted on top of the transmission rotate the dynostarter and hydrostatic oil pump for the cooling fans (1). The dynostarter provides 110 volts for the electrical systems operating on the locomotive and acts as the starter motor for the diesel engine. The hydrostatic oil pump works constantly and a small electrically operated valve diverts oil to the fans to turn them as required. For clarity these two items are not shown on the diagram below.

When the driver selects the direction for movement the transmission (9) convertor 1^st stage (gear) fills with oil and the diesel engine now begins to rotate this oil, rather like a ships propeller in water. Face to face with this 'propeller' is another similar 'propeller' which begins to rotate too and this is coupled to another cardan shaft leading to the bogie mounted Intermediate gearbox (7). In this gearbox a combination of bevel and wheel gears transmit the drive downwards. From there cardan shafts (8) transmit the drive to the axle mounted final drive gearboxes (5).

As the locomotive moves forward gaining speed the converters change (1^st to 2^nd; 2^nd to 3^rd), each convertor decreasing in physical size until the 3^rd convertor is used. This, the smallest of the three converters, then drives the train forward in the speed range between 63 and 90 mph.