World's Largest Collection of Trains.

In rail transport, a train consists of rail vehicles that move along guides to transport freight or passengers from one place to another. The guide way (permanent way) usually consists of conventional rail tracks, but might also be monorail or maglev. Propulsion for the train is provided by a separate locomotive, or from individual motors in self-propelled multiple units. Most trains are powered by diesel engines or by electricity supplied by trackside systems. Historically the steam engine was the dominant form of locomotive power through the mid-20th century, but other sources of power (such as horses, rope (or wire), gravity, pneumatics, or gas turbines) are possible.

Special kinds of trains running on corresponding special 'railways' are atmospheric railways, monorails, high-speed railways, Dinky Trains, maglev, rubber-tired underground, funicular and cog railways.

A passenger train may consist of one or several locomotives, and one or more coaches. Alternatively, a train may consist entirely of passenger carrying coaches, some or all of which are powered as a "multiple unit". In many parts of the world, particularly Japan and Europe, high-speed rail is utilized extensively for passenger travel.

Freight trains comprise wagons or trucks rather than carriages, though some parcel and mail trains (especially Traveling Post Offices) are outwardly more like passenger trains.
Trains can also be mixed, hauling both passengers and freight, see e.g. Transportation in Mauritania. Such mixed trains became rare in many countries, but were commonplace on the first 19th-century railroads.

Special trains are also used for Track Maintenance; in some places, this is called maintenance of way.

A single uncoupled rail vehicle is not technically a train, but is usually referred to as such for signaling reasons.

Passenger trains have Passenger cars. Passenger trains travel between stations; the distance between stations may vary from under 1 mile to much more. Long-distance trains, sometimes crossing several countries, may have a dining car or restaurant car; they may also have sleeping cars, but not in the case of high-speed rail; these arrive at their destination before the night falls and are in competition with airplanes in speed. Very long distance trains such as those on the Trans-Siberian railway are usually not high-speed.