Train
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 Train facts

• Motive power is provided by a separate locomotive or individual motors in self-propelled multiple units
• Although historically steam propulsion dominated, the most common modern forms are diesel and electric locomotives, the latter supplied by overhead wires or additional rails
• Other energy sources include horses, engine or water-driven rope or wire winch, gravity, pneumatics, batteries, and gas turbines
• Train tracks usually consist of two running rails, sometimes supplemented by additional rails such as electric conducting rails and rack rails, with a limited number of monorails and maglev guideways in the mix
• The word 'train' comes from the Old French trahiner, from the Latin trahere 'pull, draw'
• There are various types of trains that are designed for particular purposes
• A train may consist of a combination of one or more locomotives and attached railroad cars, or a self-propelled multiple unit (or occasionally a single or articulated powered coach, called a railcar)
• The first trains were rope-hauled, gravity powered or pulled by horses
• From the early 19th century almost all were powered by steam locomotives
• From the 1910s onwards the steam locomotives began to be replaced by less labor-intensive and cleaner (but more complex and expensive) diesel locomotives and electric locomotives, while at about the same time self-propelled multiple unit vehicles of either power system became much more common in passenger service