S-3.3, r. 2 - Regulation respecting rail safety
51. The supervisor must remove from service, until it is repaired, a car that shows one of the following defects:
(1) a wheel rim, flange, plate or hub has a crack or is broken;
(2) an axle has a crack or is bent or broken;
(3) a roller bearing has damaged external parts that are cracked, broken or bent;
(4) a roller bearing adapter is missing, cracked or broken; or
(5) a truck bolster or side frame is broken.