49 CFR § 215.127 - Defective draft arrangement.
A railroad may not place or continue in service a car, if -
(a) The car has a draft gear that is inoperative;
(b) The car has a broken yoke;
(c) An end of car cushioning unit is -
(1) Leaking clearly formed droplets; or
(d) A vertical coupler pin retainer plate -
(1) Is missing (except by design); or
(2) Has a missing fastener;
(e) The car has a draft key, or draft key retainer, that is -
(1) Inoperative; or
(2) Missing; or
(f) The car has a missing or broken follower plate.