IB Signal (G.R./S.R. 3.75, S.R. 14.13, 14.14)
Double Line / Single Line
Intermediate block signaling means an arrangement of signals on single line or double line or multiple line in which a long block section is split into two portions, each constituting a separate block section by providing an intermediate block post. A telephone is provided to contact the rear Station Master.
The intermediate block post is a ‗C‘ class station on a single line or double line or multiple line, remotely controlled from the block station in rear.
It is provided to increase section capacity, reduce detentions, reduce staff, and secure economy and efficiency in operations.
On double line, by providing IB post, a lengthy block section is divided into Axle Counter section and IB section. First section from LSS to 400 m beyond IB shall be termed as Axle Counter section and second section from 400 m beyond IB to FSS of the next block section shall be termed as IB section.
On single line, the first section shall be termed as ‗station controlled Intermediate block section‘ and the section between IB signal to FSS of block section ahead shall be termed as ‗block controlled Intermediate block section‘.
Axle counters section is controlled by axle counters. One set of axle counters is provided in advance of LSS and another set is provided 400 m in advance of IB Home signal.
LSS is interlocked with axle counter and IB signal is interlocked with block instrument.
8On SM panel, A/C indication, K1, K2, K3, K4 indications, and signal repeater indications are provided.
- K1
When train passes IB signal at ON.
- K2
When train passes LSS in OFF position.
- K3
When train passes IB signal at OFF position.
- K4
Power fails or when bulb is fused.
In addition to these indications, a buzzer is also provided.
9PB-1, PB-2, PB-3 (Analog), PB-I, Reset Buttons, PB-III (Digital) emergency release buttons are also provided.
- PB-1
To reset the axle counter when train passed IB signal at ON.
- PB-2I/Reset button
To reset the axle counter due to failure or improper counting.
- PB-3
To give co-operation to the station in rear.
For any above reasons to be reset, SM shall make an entry in concerned registers.
10Normal working (Double Line):
- a
Obtain line clear from advance station (two private numbers, one for LC and one for consent).
- b
Ensure axle counter section is free and take off LSS and IB signal.
- c
When train passes LSS, A/C indication shows occupied and K2 indication appears with buzzer and will be stopped when LSS knob or lever is normalized.
- d
When train passes IB signal (OFF), K3 indication appears with buzzer and it will be stopped when IB signal knob or lever is normalized and advance SM turns the handle of block instrument to TOL position of SGE B.I.
- e
In latest B.I UFSBI/SSBPAC, it automatically comes to TOL position with acknowledgement buttons along with buzzers.
- f
When train completely passes second axle counter (at 400 m from IB), section becomes free.
- g
Then obtain consent (1 private number) for second train and take off LSS.
- h
By the time second train reaches IB signal, first train may clear into advance station and SM will get Line clear (1 private number) to enter IB section.
- i
Rear SM can take off IB signal.
On single line (IB section), first the direction of traffic shall be established and then the line clear shall be obtained from the block section in advance as per the established direction of traffic. Only after establishing the direction of traffic, the train movement in the station controlled Intermediate block section shall be permitted.