(1) The running of every train shall, in its progress from one block station to another, be regulated by means of any one of or a combination of the following—
(a) electrical block instruments,
(b) track circuits,
(c) axle counters, or
(d) means of communication as in sub-rule (2) below.
(2) Means of communication for granting line clear between a block station to another shall be any one or a combination of the following, in that order—
(a) telephones attached to block instruments,
(b) station to station fixed telephones.
(c) fixed land line telephone,
(d) control telephone,
(e) any other secured means of communication approved in accordance with special instructions,
(3) (a) electrical block instruments, track circuit or axle counter where provided shall be used in preference to other means of communication for granting line clear;
192 THE GAZETTE OF INDIA : EXTRAORDINARY [PART II—SEC. 3(i)]
(b) Whenever the need for using any one of the means of communication arises it shall be used in order of preference as specified in sub-rule-2 above and Station Master on duty before obtaining or granting line clear shall establish the identity of the Station Master on duty at other end, in accordance with special instructions;
(c) Provided further that if only the telephone of block instrument has become defective but not the instrument itself, the Station Master on duty on both ends of the block section shall continue to obtain or grant line clear through the block instrument and shall communicate with each other using any of means of communication in that order. The condition under which the block instrument is treated as failed are described in rule 217;