balise

300px|thumb|A Eurobalise pair for ETCS/TBL+ along with a conventional TBL balise and the original Crocodile (train protection system)|Croco train stop at a signal in Belgium

A balise ( ) is an electronic beacon or transponder placed between the rails of a railway as part of an automatic train protection (ATP) system. The French word balise is used to distinguish these beacons from other kinds of beacons.