Developments, challenges, and perspectives of railway inspection robots

Railway inspection robots have been developed and used to gradually replace human inspectors in recent years. This paper reviews the recent developments on railway inspection robots and identifies the critical barriers to their widespread acceptance and applications. The inspection sensors, methods, and platforms used in railway inspection are first introduced and inspection robots used for various subjects are reviewed, including inspection for tracks, bridges, tunnels, and catenaries. To further analyse the feasibility of railway inspection robots, a prototype of a typical track inspection robot is tested in a railway line and test results are presented. After that, the current limitations of railway inspection robots are discussed and future developments for railway inspection robots are provided.