49 CFR § 229.131 - Sanders.
(a) Prior to departure from an initial terminal, each locomotive, except for MU locomotives, shall be equipped with operative sanders that deposit sand on each rail in front of the first power operated wheel set in the direction of movement or shall be handled in accordance with the requirements contained in § 229.9.
(b) A locomotive being used in road service with sanders that become inoperative after departure from an initial terminal shall be handled in accordance with the following:
(1) A lead locomotive being used in road service that experiences inoperative sanders after departure from an initial terminal may continue in service until the earliest of the following occurrences:
(i) Arrival at the next initial terminal;
(ii) Arrival at a location where it is placed in a facility with a sand delivery system;
(iii) The next periodic inspection under § 229.23; or
(iv) Fourteen calendar days from the date the sanders are first discovered to be inoperative; and
(2) A trailing locomotive being used in road service that experiences inoperative sanders after departure from an initial terminal may continue in service until the earliest of the following occurrence:
(i) Arrival at the next initial terminal;
(ii) Arrival at a location where it is placed in a facility with a sand delivery system; or
(iii) The next periodic inspection under § 229.23.
(c) A locomotive being used in switching service shall be equipped with operative sanders that deposit sand on each rail in front of the first power operated wheel set in the direction of movement. If the sanders become inoperative, the locomotive shall be handled in accordance with the following:
(1) A locomotive being used in switching service at a location not equipped with a sand delivery system may continue in service for seven calendar days from the date the sanders are first discovered inoperative or until its next periodic inspection under § 229.23, which ever occurs first; and
(2) A locomotive being used in switching service at locations equipped with a sand delivery system shall be handled in accordance with the requirements contained in § 229.9.
(d) A locomotive being handled under the provisions contained in paragraph (b) and (c)(1) of this section shall be tagged in accordance with § 229.9(a).