A vertically sliding freight elevator landing door with a safety brake (31) that deploys when a chain (26) suspending the door breaks. The safety brake is adapted for use on both panels (11,12) that slide up to open or that slide down to open. The brake, which is simple in construction and installation, comprises, principally, a caliber block (3) fixed to the door and a roller cam (34) assembled in the block. A spring (36) biases the roller cam towards a wedge lock position while a cable normally holds the roller cam in an inactive position. The cable and, therefore, the roller cam are released when the associated door suspension chain breaks. The roller cam, operating between a tilted internal surface in the caliper block and a door guide rail (16) quickly frictionally brakes the door on the guard rail.