49 C.F.R. § 229.131 Sanders.
Title 49 - Transportation
Except for MU locomotives, each locomotive shall be equipped with operable sanders that deposit sand on each rail in front of the first power operated wheel set in the direction of movement.
Title 49: Transportation
PART 229—RAILROAD LOCOMOTIVE SAFETY STANDARDS
Subpart C—Safety Requirements
Cabs and Cab Equipment
§ 229.131 Sanders.

