Section 19(7)(iv) in The Delhi Metro Airport Express Line, General Rules, 2010
(iv)if the on board Automatic Train Protection equipment is also defective, the train may be driven in High Speed Cut out Mode or Low Speed Cut out Mode of control as authorised by Traffic Controller and when authorised by the Traffic Controller, the train operator may open and operate a sealed switch and drive the train without Automatic Train Protection and in this mode the train operator shall limit the speed of the train at forty kilometers per hour in High Speed Cut Out Mode and twenty five kilometers per hour in Low Speed Cut Out Mode and be responsible for safe movement of the train.