Section 147(4)(a) in The Dedicated Freight Corridor Railway General Rules, 2018
(a)a minimum of six wagons at each end, in a load of upto sixty vehicles, shall be secured by either applying hand brakes by assistant Loco pilot or secured with at least two safety chains one at either end fastened to the rail and padlocked by the Station Master. Further at least four sprags or wooden wedges be used, two each below the outermost pair of wheels. In case the load exceeds sixty vehicles it shall be treated as two separate loads;