Train surfing (also known as train hopping or train hitching) is the act of riding on the outside of a moving train, tram or another rail transport. In a number of countries, the term train hopping is used synonymously with freight hopping, which means riding on the outside of a freight train, while train surfing can be practiced on any type of train. This type of travelling can be dangerous and even life-threatening, because there is a risk of death or serious injury from falling off a moving train, electrocution from power supply (overhead catenary wire, current collectors, resistors, etc.), colliding with railway infrastructure (bridges, tunnels, platforms, railway signals or other trains) while riding outside off structure gauge on the side or on the roof of a train, or unsuccessful attempts to jump on a moving train or off it. Today, the practice is forbidden by statutes on many railroads in the world. Despite this, it is still practiced, especially on those railroads where the trains are overcrowded.