Page 412 - IRSEM_Main Book

18.1.6 Non-Co-operative type Instruments

The requirements indicated in para 18.1.5 will apply to these instruments. In
addition, the following shall be provided in these instruments.

(a) Automatic "Train On Line": Means to ensure the instruments are set to
"Train On Line" position automatically by the entry of the train into the block
section and maintained in that position until the train has passed the Home
Signal at the receiving station and the instrument set to "Line Closed"
condition.
(b) Audible Indicator: Audible Indicator to warn the receiving station when the
train enters the block section at the sending station.

(c) Shunting Keys: Two Shunting keys, one for each line, suitably interlocked
with the block instruments for use as an authority for shunting in the block
section.

Train Detection for Proving Block Section to be Clear: On sections where
use of track circuits/Axle counters for proving the block section to be clear is to
be introduced, the following equipment shall be provided:

(a) Track circuits or Axle Counters extending from the Last Stop Signal of the
block station at one end of the block section to the other end First Stop
Signal of the block section.

(b) An indicator in each block station to show whether the block section is
occupied or not.

(c) A control to ensure that the Last Stop Signal of the block station in rear is
automatically replaced to 'ON' by the passage of a train and maintained in
that position until the train has cleared the block section.

(d) A control to ensure that the First Stop Signal is automatically replaced to
'ON' by the passage of the train.

(e) On single line, a control to ensure that the opposing Last Stop Signals of
the Block section can not be taken 'OFF' at one and the same time.

Section 2: Special Requirements of Block Working in RE Area

18.2.1 In 25 KV electrified line only following type of block instrument shall be used:

(a) Single Line:
(i) Single Line Token instrument (Neal's)

(ii) Single Line Token less Block Instrument Handle type (Daido)

(iii) Block working with Axle Counter
(iv) Block Proving by Axle Counter

(v) Block working directly from EI

Note: (i) Neal's Token instrument shall be progressively phased out.
(ii) Push button type block instrument may be used on non-electrified section taking
off from electrified section, if length of parallelism does not exceed 1.5 km.

Chapter 18: Block Instruments, BPAC & IBS Working Page 360 of 535