Are they cranked by a self starter? Is there such an immensely powerful self starter that runs off batteries and can start such a big engine?Or are they started by some gasoline powered motor?
A diesel engine is started (like an automobile) by turning over the crankshaft until the cylinders fire or begin combustion. The starting can be done electrically or pneumatically. Pneumatic starting was used for some engines. Compressed air was pumped into the cylinders of the engine until it gained sufficient speed to allow ignition, then fuel was applied to fire the engine. The compressed air was supplied by a smallauxiliary engine or by high pressure air cylinders carried by the locomotive. Electric starting is now standard. It works the same way as for an automobile, with batteries providing the power to turn a starter motor which turns over the main engine. In older locomotives fitted with DC generators instead of AC alternators, the generator was used as a starter motor by applying battery power to it.
