Canadian National Railways Rolling Stock Photographic Roster
Reporting Marks: CN
AAR Class:
NU: Sense and Braking Unit (SBU). A device mounted on the trailing coupler on the rear car of the train and coupled to the brake pipe. The SBU senses brake pipe pressure, and may sense motion and direction. This information is relayed by radio to the head end of the train to a RDU, CDU or a CLU/IDU combination. In addition, the SBU acts as a marker to indicate the rear of the train. The SBU is NOT equipped with an emergency braking feature
