What is "bahnschutzpolizei"

Bahnschutzpolizei (BSP) (Railway Protection Police) in Nazi Germany was made up of full-time and part-time police officers who were employees of the Reichsbahn (state railways). The Bahnschutzpolizei was tasked with railway safety and also with preventing espionage and sabotage of railway property. They were not subordinated to Hauptamt Ordnungspolizei, only the Deutsche Reichsbahn.