A trackside device used in NSW to trip the brakes of any train which passes a signal at STOP. A train which is tripped by this device will come to an Emergency Stop. It is used in the metropolitan areas to allow close running of suburban trains. Under some circumstance, drivers are permitted to trip through a signal during an extended delay. This implementation relies on Trainz activating the brakes when an AI driver passes a red signal. It does not activate the brakes of user controlled trains.