The diesel engine was invented by Rudolf Diesel in 1892 and experiments with diesel locomotives started soon after. The first great success was the Flying Hamburger which ran from Berlin to Hamburg in the 1930s at speeds of 125 km/h. Diesel took over from steam in the 1950s and 1960s.
Diesel locomotives are really electric locomotives that carry their own power plant. The wheels are driven by an electric motor which is supplied with electricity by the locomotive’s diesel engine.
The power output of a diesel engine is limited, so high-speed trains are electric. However diesels can supply their own electricity so need no trackside cables.
There are two other kinds of diesel apart from diesel-electrics: diesel-hydraulic and diesel mechanical.
In diesel-hydraulics, t he power from the diesel engine is connected to the wheels via a torque converter, which is a turbine driven round by fluid.
In diesel mechanicals, the power is transmitted from the diesel engine to the wheels via gears and shafts. This only works for small locomotives.
Diesel locomotives are made up from one or more separate units.
This is a typical British diesel-electric locomotive An A unit holds the driver’s cab and from the 1960s. It has a cab at both ends so that it leads the train. A B unit simply bold,. can be operated in either direction. This is one of the older generation of diesel-electrics that use DC (Direct an engine. Current) generators.
A typical diesel locomotive for that flows in only one direction. Most newer engines fast, heavy trains may consist of one take advantage of rectifiers to use the current from an A unit and six B units. AC (Alternating Current) generator. An AC generator gives a current that swaps direction many times.
The usual maximum power second. The rectifiers convert this into a direct current. output from a single diesel AC generators are far more powerful and efficient.