49 C.F.R. § 215.129
Defective cushioning device
A railroad may not place or continue in service a car if it has a cushioning device that is—
(a) Broken;
(b) Inoperative; or
(c) Missing a part—
A railroad may not place or continue in service a car if it has a cushioning device that is—
(a) Broken;
(b) Inoperative; or
(c) Missing a part—