(1) Whenever the Station Master on duty is unable to obtain or grant line clear, or take it to train on line position, or close the section through the instrument on account of failure of block instrument or Block Proving through Axle Counter or any other reason, the instrument shall be treated as failed. In such a case, line clear shall be obtained through other permitted means of Communication in accordance with the rule 90.
(2) If the failure of line clear instrument has taken place after departure of a train such that Station Master on duty is unable to take it to train on line position, or close the section through the instrument, the Station Master after confirming complete arrival of last train under exchange of private number with the Station Master of block station in advance shall normalise the instrument by resetting axle counters and take line clear for the subsequent train.
(3) When line clear is taken by means other than block instrument, an entry to this effect shall be made in Train Signal register, and the private number exchange by Station Master on duty of station in advance shall be mentioned in the line clear ticket granted to the Loco pilot.
(4) The line clear ticket shall always be prepared by Station Master on paper in accordance with sub- rule (2) of the rule 97 irrespective of the manner of its delivery to the Loco pilot as mentioned in clause (b) of sub- rule (1) of the rule 97.
(5) The Station Master on duty shall switch on the buzzer where provided to remind him of the abnormal condition, otherwise shall place a placard bearing words 'Block instrument failed'.
D - Temporary single line working on a double line section