Diesel locomotives

A diesel locomotive carries its own power plant and can run on any line, electrified or not. In most cases the diesel engine drives a generator or alternator that feeds electric traction motors (diesel-electric transmission). Smaller locomotives and shunters often use hydraulic or mechanical transmissions instead.

Diesel locomotives replaced steam on most of the world's railways between the 1940s and the 1970s. They remain the backbone of freight traffic in North America, Russia, Australia and Africa, where builders such as EMD, GE (now Wabtec), Kolomna or Luhansk produced thousands of units.

Useful figures to compare are the prime mover (engine model), the power output, the tractive effort, the weight and axle load, and the top speed. This category also includes a few gas-diesel and gasoline locomotives.