Section 101(3)(iii) in Delhi Motor Vehicles Rules, 1993
(iii)if the trailer is or trailers are being drawn by a locomotive, notwithstanding that the brake or the trailer can be operated by the driver or some other person on the locomotive, not less than one person on each 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 (bb) of clause (i).