Page 424 - IRSEM_Main Book

(g) A Signal Post Telephone (SPT) or any approved type communication shall
be provided at the IBS post for communication with the station in the rear.

(h) IBS system needs distant and inner distant signal where applicable for pre
warning of IBS.

(i) IBS works like Class C station & IB Distant signals are to be provided to
match with the section signaling.

(j) IBS block overlap of 400 m shall be separately monitored.

(k) Where axle counters are provided, resetting arrangements are also to be
provided.
(l) Provision must be there to indicate that a train has passed IBS at “On”
Position/blank.

(m) IBS system needs panel with various indications and push buttons at each
block station pertaining to direction of traffic.

(n) IB Signal shall be provided with a marker consisting of a white coloured
disc with letter 'IB' in black.

(o) Control of IBS lies with the SM of station in rear.

18.12.2 Resetting Operations: There are two types of resetting operations which
requires co-operation of the other end Station Master.

(a) When a train passes IBS at “On” position/blank.

(b) When Axle Counter fails.

18.12.3 IBS system will permit only one train in the entire block section, when a train
passes IBS at “On” position or axle counter is not clear even after the passage
of the train beyond the axle counter section.

Procedure to be followed by the Loco Pilot to pass IBS at “On” position/blank
as per GR 3.75:

(a) When phone communication is available between IBS and rear station, the
loco pilot shall stop his train in rear of the IBS and contact the SM of block
station in rear on SPT, then pass the defective IBS, if authorized by SM.

(b) When phone communication is not available between IBS and the rear
station, the loco pilot after waiting for 5 minutes can go beyond IBS at a
speed not more than 15 kmph which should be reduced to 8 kmph in case
of inadequate visibility like fog, night conditions etc. The loco pilot should
proceed at restricted speed till he reaches advance station.

Monitoring is required through indication for IBS blank.

Chapter 18: Block Instruments, BPAC & IBS Working Page 372 of 535