Abstract: In a railway wheel braking unit, a braking flange carrying a friction pad for engaging the wheel tread is detachably mounted on the main brake shoe by a rod structure that projects with a snug fit into an arch on the main shoe, a retaining pin passing through aligned openings in the arch side walls and the rod structure.

Abstract: A slack adjuster to be used in association with the actuating cam of an internal expanding shoe type brake comprises a body member embodying a brake-actuating arm movable around the axis of the cam shaft, a worm rotatably mounted in the body member and meshing with a worm wheel keyed to the cam shaft, a member oscillatably mounted on the body member and co-operating with a non-rotatable member to impart motion to the worm through a sprag clutch when a pre-determined angular movement of the brake-actuating arm is exceeded, and a friction clutch also in the drive from the oscillatable member to the worm and operable to dis-engage the drive if attempt is made to rotate the worm while it is still under braking load.