Yardmasters are the traffic controllers of the yards and terminals in the railroad industry. Using computers and supervising switching equipment in the yard tower, they route trains and engines within the yard. The yardmaster reads switching orders and schedules to determine the time trains will arrive or depart, the sequence of movement and the routing of trains onto tracks. He or she receives and transmits switching orders to and from yard crews.

Yardmasters also supervise clerical staff in the yard offices.