At interconnected traffic signals, the controller assembly, consisting of the traffic signal controller and cabinet, shall provide the operation detailed below relative to the preemption functionality and operation.

The controller assembly shall be provided with all hardware, software and firmware necessary to provide the operation described herein. The designer, contractor and/or traffic signal technician should closely review the functional requirements of the railroad preemption operation to assure that the equipment is capable of performing the functions as specified. In many cases, the railroad circuits have been designed to provide and support the specific functionality. As a result, no exceptions will be permitted to these requirements.