Rail transport is a type of land transport in which locomotives pull train cars on two parallel tracks. The traditional way is steel wheel travel, but the broad definition of railway transport includes maglev train, cable car, ropeway and other non-steel wheel travel, or rail transport. Rails provide an extremely smooth and hard medium for the wheels of the train to roll on with minimal friction, making it more comfortable for the people on them, and it also saves energy. If properly configured, rail transport can use 50 to 70 percent less energy than road transport to carry the same weight. Moreover, the rail can evenly distribute the weight of the train, so that the load capacity of the train is greatly increased.

Railway sometimes refers to a railway "line" such as Beijing-Guangzhou railway, sometimes refers to the collection of railway lines including old lines, new lines or first and second lines, such as a new railway under the name of a railway expansion or belongs to a railway system.

The railway grade in the era of high-speed railway is very complicated, including road network grade, speed grade, passenger and cargo grade and so on. The high-speed rail class is higher than the national railway Class Ⅰ, which is either fast or ordinary.

Standard track is relative to meter track and wide track. In the third division of the speed scale, regular rail is compared to express rail and high speed rail, and dichotomous rail is compared to rapid rail and rapid rail.