Railroads use flanged wheels rolling over fixed rails for human transportation; the vehicles on these rails are commonly called trains because they are usually composed of a train of cars linked together. Trains have distinct characteristics that have called for specialized legal and policy regulation, and to some extent for the application of ethical principles.

Prior to the development of steam locomotion, early horse-drawn trains ran on tracks serving mines, where the ground was otherwise too uneven for wheeled vehicles. The first horse-drawn trains began operating at English coal mines in the 1630s. In 1758, the British Parliament established the Middleton Railway in Leeds; it began to adopt steam locomotives in 1812. The Middleton Railway claims to be the oldest railway in the world; however, at this time it carried only freight, not passengers. The first public steam-operated passenger railway was the Stockton & Darlington in England, which began operations in...