Types of tractive units by source of power
Types of tractive units by source of power
- Electric tractive unit. Tractive unit with one or more electric motors, deriving current primarily from overhead wires, conductor rails or accumulators (battery) carried on locomotive.
A tractive unit that can derive current from both overhead wires and conductor rails or from accumulators (battery) is classed as ‘full electric’ (electric conductors and battery), within electric tractive units.
A tractive unit so equipped that also has an engine (diesel or other) to supply current to the electric motor when it cannot be obtained from an overhead wire or from a conductor rail is classed as a ‘dual mode’ vehicle within electric tractive units.
- Magnetic levitation (maglev). Tractive unit using magnets that control the train’s stability and speed for propulsion. It is a specific type of electric tractive unit.
- Diesel tractive unit. Tractive unit with a diesel engine as the main source of power, irrespective of the type of transmission installed.
- Diesel-electric tractive units (or multiple units) that are propelled by electric motors (battery) and derive energy from a diesel generator are classed as ‘hybrid’ vehicles within diesel tractive units (or multiple units). Bio-diesel is included in diesel.
- Alternative drive tractive unit. This notion groups the sources of power that differ, in terms of their energy type and energy efficiency, from the technologies commonly used on the market (electricity and diesel).
- Steam. Tractive unit, whether cylinder- or turbine-driven, in which the source of power is steam, irrespective of the type of fuel used.
- Hydrogen. Tractive unit (or multiple unit) powered primarily by hydrogen.
Hydrogen fuel cell tractive units are included.