Section 21(3) in The Delhi Metro Airport Express Line, General Rules, 2010
(3)The traffic controller shall verify as far as practicable from indications on his diagram that the problem is not caused by a track side fault or another train and if no cause is apparent, he shall instruct the train operator to select the Restricted Manual mode and try to move ahead exercising utmost vigilance so, that he may stop short of any obstruction.
