Section 26(3) in The Delhi Metro Airport Express Line, General Rules, 2010
(3)In Coded Manual mode, the train operator shall regulate the speed of trains according to the cab signals, the maximum permissible speed shall not be exceeded and the speed of the train shall be such that it can be stopped within the distance indicated, as being the limit of safety and the failure to do so shall result in irrevocable application of emergency brakes.
