Train surfing (also known as train hopping or train hitching) is typically a reckless, dangerous, and illegal act of riding on the outside of a moving train, tram, or other forms of 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 extremely dangerous and even life-threatening, because there is a risk of death or serious injury due to falling off a moving train, electrocution by the power supply (overhead catenary wire, third rail, current collectors, resistors, etc.), colliding with railway infrastructure such as bridges, tunnels, station platforms, trackside buildings, railway signals or other trains, while riding outside of structure gauge on the side or on the roof of a train, or unsuccessful attempts to jump onto a moving train or off it. Today, the practice is illegal by statutes on many railroads in the world. Despite this, it is still practiced, especially on those railroads where the trains are overcrowded.