Section 50(1)(ii) in The Delhi Metro Airport Express Line, General Rules, 2010
(ii)the Traffic Controller shall, if possible, instruct the train operator of the following train to drive as close to the stalled train as possible under Coded Manual mode and at the limit of authority under cab signaling, the Traffic Controller shall instruct the train operator of the assisting train to change to Restricted Manual mode, and to proceed at reduced speed and stop about ten meters short of the stalled train;