Trackage

A typical track consists of two parallel steel (or in older networks, iron) rails, generally anchored perpendicular to members called crossties or sleepers of timber, concrete, or steel to maintain a consistent distance apart, or gauge. The rails and crossties (sleepers) are usually then placed on a foundation made of compressed earth on top of which is placed bed of ballast to distrubute the load from the crossties and to prevent the track from buckling (bending out of its original configuration) as the ground settles over time under the weight of the vehicles passing above.

The vehicles traveling on the rails are arranged in a train; a series of individual powered or unpowered linked vehicles, displaying markers. These vehicles (referred to, in general, as cars, carriages or wagons) move with much less friction than do vehicles riding on rubber tires on a paved road, and the locomotive that pulls the train tends to use energy far more efficiently as a result.[citation needed]Trackage, consisting of railroad ties (sleepers) and ties and rails, may be prefabricated or assembled in place. Rails may be segments welded or bolted, and may be of a length comparable to that of a railcar or two or may be many hundreds of feet long.On curves the outer rail may be at a higher level than the inner rail. This is called superelevation or cant. This reduces the forces tending to displace the track and makes for a more comfortable ride for standing livestock and standing or seated passengers. This will be effective at a limited range of speeds, however.