Abstract: A "snow brake" control system for a railway vehicle in which an electronic timing circuit is operative in response to the operator's brake valve device being moved to its brake release position to provide an output signal that acts through a relay switch to deenergize a magnet valve that normally interrupts communication of "snow brake" control pressure to the system relay valve in order to withhold "snow brake" operation for a predetermined period of time sufficient to allow the vehicle brake units to release the brakes and thereby effect operation of the brake unit slack adjuster mechanism. When the time period expires, the timing circuit output signal disappears and the magnet valve becomes energized to reestablish "snow brake" control pressure during the remainder of the brake release period to maintain a light brake application in effect.