Section 219(1)(c) in The Bihar Motor Vehicles Rules, 1992
(c)if the trailer is or trailers are being drawn by a locomotive, notwithstanding the brakes of the trailer or trailers can be operated by the driver of some other person on the locomotive, not less than one person on such trailer and not less than two persons on the last trailer in train, one of whom shall be the person required by the provisions of sub-clause (ii) of clause (a).