(a) Division 2.1 (flammable gas) materials may not be loaded, transported, or stored in a rail car equipped with any type of lighted heater or open-flame device, or in a rail car equipped with any apparatus or mechanism utilizing an internal combustion engine in its operation.
(b) Division 2.1 (flammable gas) materials may not be loaded in a truck body or trailer equipped with any type of lighted heater or any automatic heating or refrigerating apparatus when such truck bodies or trailers are loaded on flatcars except as provided in paragraph (c) of this section.
(c) Heating or refrigeration apparatus may be operated on a motor vehicle loaded on a flatcar when the motor vehicle is loaded with Division 2.1 (flammable gas) materials only if:
(1) The lading space is not equipped with any electrical apparatus that is not non-sparking or explosion-proof;
(2) There is no combustion apparatus in the lading space;
(3) There is no connection for the return of air from the lading space to any combustion apparatus; and
(4) The heating system conforms to Sec. 393.77 of this title and does not heat any part of the lading over 54 C (129 F). [Amdt. 174-26, 41 FR 16092, Apr. 15, 1976, as amended by Amdt. 174-68, 55 FR 52682, Dec. 21, 1990; 56 FR 66281, Dec. 20, 1991]