Section 218(1)(b) in The Dedicated Freight Corridor Railway General Rules, 2018
(b)(i)as a reminder of suspension of signals at either ends of the section where single line working is introduced and at all the intermediate stations signal buttons shall be covered with stop plugs, as also,(ii)as a reminder of suspension of block instruments, in case of Absolute Block System of working, the block instruments at either ends of the section where single line working is introduced and at all the intermediate stations shall be kept in train on line position and locked with keys kept in safe custody in Station through out the period of abnormal working; and-(iii)Buzzer alarm, if provided shall also be switched on as a reminder of abnormal working.