Section 19(3) in The Delhi Metro Airport Express Line, General Rules, 2010
(3)Running Lines.- (i) the Signaling system on the running line shall be a full Automatic Train Protection system;(ii)if the speed which permits a train running on Automatic Train Protection to stop under normal braking within a limit of safety, is exceeded, an irrevocable emergency brake application is automatically made which ensures that the train does not proceed beyond the safe limit;(iii)normal operation of the train running on Automatic Train Protection is monitored from indication on the train operator's console and each main running line is duly signaled for operation;(iv)certain lines are equipped for automatic train operation with provision for the train operator to assume manual control of the train if required;(v)in the event of failure of the Automatic Train Operation equipment and on lines not so equipped, train operators shall control their train up to the speed indicated on the console;(vi)where no cab indication is available, train shall be automatically restricted to a maximum speed of twenty five kilometers per hour in "Restricted manual" mode;(vii)fixed signals are provided at approach to all points and crossings of the interlocking area.
