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A locomotive is the part of a train that makes the train move. Normally, it is the first part of the train, and has an engine.

Types of locomotives[change | edit source]

Diesel locomotive[change | edit source]

Three diesel locomotives, coupled together to power a long, heavy train

A diesel locomotive is a powered by a diesel engine. The diesel engine may drive the locomotive's wheels directly via a gearbox, shaft or chain (called mechanical transmission); by generating electricity which is in turn used to power the wheels (called diesel-electric); or by using a hydraulic transmission system (diesel-hydraulic). Diesel locomotives are extremely popular worldwide, due to their ease of use and reliability. They are more powerful than steam locomotives and do not need an expensive power grid like electric locomotives.

Steam locomotive[change | edit source]

A steam locomotive

A steam locomotive uses wood, coal or oil (but mostly coal) to heat water in a boiler, which turns into steam which is used in pistons to power the train. Steam locomotives are not widely used any more due to their operational costs, especially the fuel costs; steam locomotives are now mostly only used on tourist railroads.

Walschaerts valve gear in a steam locomotive. In this animation, the red colour represents live steam entering the cylinder, blue represents expanded (spent) steam being exhausted from the cylinder. Note that the cylinder receives two steam injections during each full rotation; the same occurs in the cylinder on the other side of the engine.

Electric locomotive[change | edit source]

A GG1 electric locomotive

An electric locomotive is a locomotive that runs on electricity as the name suggests. Electric locomotives cost the least to operate, but it costs the most to build the track and provide electricity, making it only the second next used type, behind diesel locomotives.