Yes, it is strictly illegal to go on train tracks in the United Kingdom, an act legally defined as "trespassing on the railway." Under the British Transport Police enforcement guidelines and the Railway Regulation Act, trespassing is a criminal offense that carries a maximum fine of £1,000 and can result in a permanent criminal record. Beyond the legal ramifications, the physical dangers are extreme; modern trains in the UK are incredibly quiet and can travel at speeds up to 125 mph, meaning they can reach a person before they are even heard. Additionally, many tracks in the South of England and the Merseyrail network are powered by a "third rail," which carries 750 volts of electricity—enough to be fatal instantly upon contact. The railway is considered private property, and Network Rail works closely with the police to use CCTV and motion sensors to catch and prosecute anyone who steps beyond the designated public platforms or authorized pedestrian level crossings.