ATC has developed the Railway level crossing Active Advanced Warning Sign (AWSC4) to provide motorists approaching a level crossing with advanced warning of an approaching train.  They are typically installed in remote, rural roads with high approach speeds. The Active Advance Warning Sign Controller system consists of static warning signs enhanced with flashing yellow lights located up to 200m from the railway crossing. 

The Active Advance Warning Sign devices are there to aid motorists in being alerted well ahead of reaching the railway crossing. This is especially so where visibility on approach is limited due to geographical or weather conditions. The Active Advance Warning Sign controller activates the flashing yellow lights upon receipt of an appropriate input signal from the railway level crossing protection system. The flashing yellow lights are de-activated upon receipt of an appropriate input from the railway crossing control system when a train has cleared the level crossing.


The AWSC4 Advanced Warning Sign Controller is designed to communicate critical status changes back to a central monitoring system using the latest generation high speed 3G mobile telephony network (UMTS). Conversely, service personnel can dial into the AWSC4 to interrogate the unit for real time status information including the state of the UPS and Mains AC. The AWSC4 Advanced Warning Sign Controller software has been designed in a modular fashion to allow it to communicate using industry standard protocols.

UPS Backup

One of the main features of the product is the built-in Uninterruptible Power Supply (UPS) that provides greater than 6 hours autonomy should the Mains AC supply be cutoff. The UPS also has the option of being connected to an Auto Transfer Switch (Bypass) that allows for the Mains AC to bypass the UPS Charger and feed the load directly. One of the key features of the AWSC4 is that the internal flasher unit is activated directly by the rail call interface and will drive the warning signs irrespective of the state of the Logic Rack. ATC have designed this product with fail-safe features that ensure motorists get the correct lanterns lighting should there be an internal malfunction.

LED Lanterns

The AWSC4 Advanced Warning Sign Controller is designed to detect and drive up to 4 Warning Signs with 2 Yellow LED Lanterns each. ATC have chosen to use Type Approved low power LED Lanterns that are AS2144 compliant running on Extra Low Voltage of 42V AC. This feature represents the latest in safety design. In the event of a vehicle accident, the risk of the public coming into contact with lethal voltages is minimized.