Block Instrument Maintenance and Inspection

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Questions and Answers

What is the maximum interval for overhauling Single Line Token Block Instruments?

Twelve years

Five years

Ten years (correct)

Eight years

What is the required maintenance interval for block earth examinations by the Section Engineer (Signal)?

One month (correct)

Three months

Two months

Six months

What action should be taken if the resistance of block earths exceeds 10 ohms?

No action required

Reduce resistance by providing additional earths in parallel (correct)

Replace the block instrument

Increase the maintenance frequency

In AC electrified areas, how many different earths should be provided for Discharger and Block Earth?

Two Signup and view all the answers

Which type of block instruments does not require overhauling?

Push Button Token less Block Instruments Signup and view all the answers

What should be checked to ensure the efficiency of the filter using the four Terminal Condenser?

Connection of the DC circuit through the plate or foil Signup and view all the answers

What condition must the receiver diaphragms meet for proper function?

They must be at the correct distance from the pole pieces Signup and view all the answers

When a pair of block instruments falls in different contiguous Railway/Division, who maintains them?

One agency Signup and view all the answers

What should be ensured regarding Axle Counter track equipment and UFSBI?

They should be maintained as per OEM manuals. Signup and view all the answers

What is one requirement for the maintenance of Embedded type Block working?

Follow OEM maintenance manual schedules. Signup and view all the answers

What does Intermediate Block Signalling (IBS) achieve?

Increases section capacity by splitting long block sections. Signup and view all the answers

Where does the rear section of the station controlled intermediate block section start?

At the LSS of the rear station. Signup and view all the answers

What may the Railways prescribe at stations with heavy traffic?

More frequent inspections as necessary. Signup and view all the answers

What consideration must be taken into account when placing IBS?

Steeper gradients and signal visibility. Signup and view all the answers

What is the purpose of the 400 meters block overlap in the rear section?

To ensure safety in signal transitions. Signup and view all the answers

What can screw up the operation of Block Proving by Axle Counter?

Ignoring OEM manual instructions. Signup and view all the answers

What must be ensured regarding the safety catch near the spring clutch shaft of a single line token instrument?

It must be functional and free to move without friction. Signup and view all the answers

How often should the pin of the token indicator be oiled with axle oil?

Once a fortnight Signup and view all the answers

What shapes should notches in the rack of a token instrument be?

Square and correctly shaped Signup and view all the answers

What specific measurement is required for the locking Pawl of the instrument?

Correctly shaped and square ended with width of 9.5 mm Signup and view all the answers

Which part of the token instrument is specifically checked for being free to move about its fulcrum pin?

The locks rocker arm Signup and view all the answers

What is indicated by a red signal on the token indicator?

It should not be possible to take handle to 'Train Going To' position. Signup and view all the answers

What should be done regarding the locking assembly of double line block instruments during overhauling?

It should be replaced irrespective of its condition. Signup and view all the answers

In the case of Tablet instruments, what must be ensured about the tablet holding arm release lever?

It should work only after full rotation and handle release. Signup and view all the answers

What does the block controlled Intermediate Block section include?

The area between the IBS and home signal including block overlap Signup and view all the answers

Who controls train entry into the rear section known as the station controlled intermediate block section?

LSS of rear station Signup and view all the answers

Which system is responsible for providing indication that a train has passed IBS at 'On' position?

IBS system itself through its monitoring Signup and view all the answers

What color is the marker on the IB Signal and what does it signify?

White disc with letter 'IB' in black, indicating the IBS position Signup and view all the answers

What is required when two types of resetting operations occur at the IBS?

Co-operation of the other end Station Master Signup and view all the answers

What type of signals are needed for the IBS system for pre-warning?

IB Distant signals alongside inner distant signals Signup and view all the answers

How is train entry into the advance section controlled?

By the IBS in that direction Signup and view all the answers

What does the system permit concerning train movement in an entire block section?

Only one train is allowed when conditions are met Signup and view all the answers

Study Notes

Block Instrument Telephones

Flexible cords and condensers isolate block instrument circuits from other circuits
No direct current path between circuits
Receiver diaphragms must be correctly positioned and secured
Receiver earpiece must fit correctly and be securely fastened
Maintenance of different block instruments in different railway divisions handled by one agency

Overhauling of Block Instruments

Single Line Token Block Instruments: 10-year overhauling interval
Double Line Block Instruments: 7-year interval
Push Button Token less Block Instruments, UFSBI Block panel, and Embedded block working in Electronic Interlocking do not require overhauling
Associated polarized relay overhauled with block instrument

Block Earths

Section Engineer (Signal) inspects block earths every month
Senior Section Engineer (Signal) inspects every three months
Resistance testing every 12 months using Annexure: 19-A3
Resistance exceeding 10 ohms requires additional parallel earths
Separate earths for discharger and block in AC electrified areas
Four Terminal Condensers in filter connected to complete DC circuit through plates/foils; a break in foil or connection might disrupt filter efficiency

Single Line Token Instruments

Safety catch on spring clutch shaft must be in position and fully functional
Token indicator must be free-moving
Oil token indicator pin fortnightly with axle oil
Verify "No token" lock functionality
"Train Going To/From" locks' rocker arms must be free-moving, 1mm above rack; otherwise, replace
All wear-prone instrument parts replaced during overhauling
Locking pawl shaped correctly; square-ended and 9.5mm wide.
Tablet instrument arm lever releases correctly after full rotation
Rack notches need to be correctly shaped and square

Single Line Tokenless Instruments (Push Button Type)

Routine maintenance procedures in para 18.5.2
Double Line Block Instruments (SGE Type): Locking assemblies replaced during every overhauling.
Ensure all wear-prone parts replaced during overhauling

Block Proving by Axle Counter

Axle counter track equipment and UFSBI values maintained within OEM manual parameters
Electronic equipment signal levels within permissible limits

Block Working Built into Electronic Interlocking

Embedded block working maintained per Electronic Interlocking and VDU maintenance schedules
Related equipment operates per instructions

Intermediate Block Signalling (IBS)

IBS splits longer sections into rear and advance portions near bifurcations
Rear/Advance sections (station controlled & block controlled) monitored by axle counters or track circuits
Train entry into each section controlled by appropriate devices: LSS or IBS
Rear section controlled by LSS (Local Section Signal).
Advance section Controlled by IBS (Intermediate Block Signal)

Resetting Operations

Train passes IBS at "On" position/blank: requires cooperation with rear station master
Axle counter failure requires cooperation

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Description

This quiz covers the essential practices and schedules for maintaining block instruments used in railway communications. It includes topics such as the proper installation of receivers, overhauling intervals, and the inspection frequency for block earths. Test your understanding of these vital components in ensuring safe and effective railway operations.