WAdvanced Civil Speed Enforcement System
WALSN
WAutomatic train control
WAutomatic train protection
WAutomatische treinbeïnvloeding
WBalise
WCommunications-based train control
WContinuous Automatic Warning System
WContrôle de vitesse par balises
WCrocodile (train protection system)
WDefect detector
WEBICAB
WEmergency brake (train)
WEurobalise
WEuropean Train Control System
WGeschwindigkeitsüberwachung Neigetechnik
WIntegra-Signum
WKLUB (train control system)
WLinienzugbeeinflussung
WLS 90
WSignaling of the New York City Subway
WPositive train control
WPulse code cab signaling
WPunktförmige Zugbeeinflussung
WSistema Supporto Condotta
WTrain automatic stopping controller
WTrain stop
WTransmission Voie-Machine
WZUB 1xx