Section 223(1)(A) in The Dedicated Freight Corridor Railway General Rules, 2018
(A)on a double line section where trains on the adjacent line run in the opposite direction,-(i)if it is obvious that the adjacent line is obstructed the Loco pilot shall depute his Assistant Pilot to get down and show flashing red danger signal to any train approaching from the front; and(ii)if in doubt whether the adjacent line is obstructed or not,-