I would stop, for the same reasons the school bus drivers stop.
§ 392.10: Railroad grade crossings; stopping required.
(b) A stop need not be made at:
(1) A streetcar crossing, or railroad tracks used exclusively for industrial switching purposes, within a business district, as defined in § 390.5 of this chapter.
(2) A railroad grade crossing when a police officer or crossing flagman directs traffic to proceed,
(3) A railroad grade crossing controlled by a functioning highway traffic signal transmitting a green indication which, under local law, permits the commercial motor vehicle to proceed across the railroad tracks without slowing or stopping.
(4) An abandoned railroad grade crossing which is marked with a sign indicating that the rail line is abandoned,
(5) An industrial or spur line railroad grade
crossing marked with a sign reading “Exempt.” Such “Exempt” signs shall be erected only by or with the consent of the appropriate State or local authority.