The train
Motive power is provided by a separate locomotiveor individual motors in self-propelled multiple units. Although historically steampropulsion dominated, the most common modern forms are dieseland electric locomotives, the latter supplied by overhead wires or additional rails. Other energy sources include horses, rope or wire, gravity, pneumatics, batteries, and gas turbines.
Train tracks usually consists of two, three or four rails, with a limited number of monorailsand maglevguideways in the mix.
The word 'train' comes from the Old Frenchtrahiner, from the Latintrahere 'pull, draw'.
