Usually an illegal sport, train surfing involves riders climbing or "surfing" on the outside of a moving train or subway. The practice is a serious issue in South Africa, where many young people have been killed or injured. The 'sport' was made popular in the 1980s in Germany, where it was called "S-Bahn Surfing". The phenomenon was then forgotten, but in 2005 it was rediscovered by a gang from Frankfurt, Germany. The leader of the crew who called himself "The Trainrider" famously surfed the InterCityExpress, the fastest train in Germany.