49 CFR § 230.101
Steam locomotive driving journal boxes
November 18, 2020
(a) Driving journal boxes. Driving journal boxes shall be maintained in a safe and suitable condition for service. Not more than one shim may be used between the box and bearing.
(b) Broken bearings. Broken bearings shall be renewed.
(c) Loose bearings. Loose bearings shall be repaired or renewed.