A passenger train includes passenger-carrying vehicles and can often be very long and fast. One notable and growing long-distance train category is high-speed rail. In order to achieve much faster operation at speeds of over 500 km/h (310 mph), innovative maglev technology has been the subject of research for many years.
A passenger train consists of one or more locomotives and (usually) several coaches. Alternatively, a train may consist entirely of passenger-carrying coaches, some or all of which are powered; this is known as a "multiple unit". In many parts of the world, particularly the Far East and Europe, high-speed rail is used extensively for passenger travel. Freight trains consist of wagons or trucks rather than carriages
In the United Kingdom, a train hauled using two locomotives is known as a "double-headed" train. In Canada and the United States it is quite common for a long freight train to be headed by three or more locomotives. A train with a locomotive attached at both ends is described as "top and tailed", this practice typically being used when there are no reversing facilities available. Where a second locomotive is attached temporarily to assist a train when ascending steep banks or gradients (or to provide braking power for a descent), this is referred to as banking in the UK. Many loaded trains in the United States are assembled using one or more locomotives in the middle or at the rear of the train, which are then operated remotely from the lead cab. This is referred to as "DP" or "Distributed Power."
