Electronics Installation and Safety Standards
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Questions and Answers

What is the required resistance of the earthing system for instruments?

  • Less than 5 ohms
  • Less than 10 ohms (correct)
  • Less than 20 ohms
  • Less than 15 ohms

What is the minimum diameter required for the earth wire?

  • 4 mm (correct)
  • 6 mm
  • 2 mm
  • 8 mm

How far must a separate earth for an instrument be buried below ground?

  • 2.5 meters
  • 1 meter
  • 2 meters
  • 1.5 meters (correct)

What is a key condition for the installation of Token instruments?

<p>The token from one section cannot be placed in another instrument at that station (A)</p> Signup and view all the answers

Which type of instrument does not require a separate earth?

<p>Block instruments with metallic return (B)</p> Signup and view all the answers

What must be ensured about the movement of mechanical parts in instruments after installation?

<p>They must be free to move without undue friction (D)</p> Signup and view all the answers

What must not be present in the earth wire during installation?

<p>Sharp bends or spirals (A)</p> Signup and view all the answers

What configurations should consecutive block sections be provided with?

<p>A, B &amp; C (B)</p> Signup and view all the answers

What is the minimum total pick up time for relays used in block instruments?

<p>300 msec (A)</p> Signup and view all the answers

Which condition must be satisfied for the shunting key to be removed?

<p>In 'Line Closed' or 'Train Going To' condition (D)</p> Signup and view all the answers

What prevents the Last Stop Signal from being taken 'OFF'?

<p>When the commutator is in any position other than 'Line Clear' (B)</p> Signup and view all the answers

When is the Last Stop Signal automatically replaced to 'ON'?

<p>When the train enters the block section (D)</p> Signup and view all the answers

What type of relay should not be used for stick circuits of the block instrument?

<p>Quick acting relays (A)</p> Signup and view all the answers

What is the minimum insulation resistance value required between individual insulated circuits and Earth for block instruments?

<p>10 mega ohms (A)</p> Signup and view all the answers

What must be checked before the 'Train on Line' indication appears?

<p>The commutator handle must be locked (D)</p> Signup and view all the answers

Which of the following is NOT a requirement for the installation of single line tokenless block instruments?

<p>Must have complex access for maintenance (B)</p> Signup and view all the answers

What condition must be met for the Last Stop Signal at the sending station to be taken 'OFF'?

<p>The receiving station instrument should be set to 'Train Coming From' condition. (A), The sending station instrument must be set to 'Train Going To' condition. (D)</p> Signup and view all the answers

Which of the following is NOT recorded in the register of block instruments maintained by the Senior Section Engineer?

<p>Operational issues encountered (D)</p> Signup and view all the answers

What operation is required for block release in the system?

<p>Operation of two track circuits sequentially (D)</p> Signup and view all the answers

Which of these checks should be conducted during the installation of block instruments?

<p>All nuts and bolts should be secure and complete. (C)</p> Signup and view all the answers

How is block release achieved in a single line tokenless block instrument?

<p>By the operation of two track circuits sequentially. (B)</p> Signup and view all the answers

What will happen to the Last Stop Signal when a train enters the block section?

<p>It will be maintained in the 'ON' position until conditions return to safe. (C)</p> Signup and view all the answers

Which observation is required for the Front Panel of Push Button type instruments during installation?

<p>It should be free from splitting, twisting, or warping. (D)</p> Signup and view all the answers

What should be done before measuring insulation resistance to block instruments?

<p>Remove all external connections to the block instrument. (B)</p> Signup and view all the answers

What document must technicians use to keep track of token balances?

<p>Token Balance Book (A)</p> Signup and view all the answers

Which personnel are required to sign the Token Balance Book when tokens are extracted?

<p>Both Station Masters involved (B)</p> Signup and view all the answers

Under what condition can tokens be extracted or replenished in the instruments?

<p>When the instruments are in the 'Line Closed' position (C)</p> Signup and view all the answers

What is the minimum token balance that triggers a warning message to the technician?

<p>Six tokens (B)</p> Signup and view all the answers

What must each sectional JE/SSE (Signal) do regarding the census of tokens?

<p>Take a census of tokens at least once in six months. (C)</p> Signup and view all the answers

Who is responsible for the safe operation of the token instruments?

<p>The Technician operating the instruments (A)</p> Signup and view all the answers

What is required from the Traffic Department regarding token pouches?

<p>Damaged pouches should not be used (A)</p> Signup and view all the answers

What action should be taken for damaged tokens?

<p>They should be removed, broken up, and returned to Stores. (A)</p> Signup and view all the answers

What is recorded on Card No. S&T/TL regarding lost tokens?

<p>Particulars of lost tokens. (C)</p> Signup and view all the answers

What must technicians do to ensure the locks on instruments are secure?

<p>Conduct fortnightly inspections (B)</p> Signup and view all the answers

What happens when a token is lost and not found after a thorough search?

<p>A joint certificate is issued and a circular is sent out. (A)</p> Signup and view all the answers

Which of the following statements is true regarding bell signals in operations?

<p>Authorized code of bell signals is still necessary (B)</p> Signup and view all the answers

When a lost token is replaced, what should be considered?

<p>The new token should be the next higher number in the series. (C)</p> Signup and view all the answers

What should be done with the found lost token after it has been replaced?

<p>It should be broken and returned to stores. (C)</p> Signup and view all the answers

How often should the record of tokens be updated in the Signal History Book?

<p>Every six months. (C)</p> Signup and view all the answers

What must supervisors do when a token is lost?

<p>Prepare a joint certificate for higher authorities. (B)</p> Signup and view all the answers

Flashcards

Earthing for instruments

Each instrument needs a separate, buried earth connection. This connection, no less than 1.5 meters deep and 2.5 meters from any other earth, must have a resistance of no more than 10 ohms.

Earth wire size

The earth wire must be at least as thick as the line wire and not less than 4 mm in diameter.

Earth wire construction

The earth wire should be straight and protected from damage, with all connections soldered firmly.

Token instrument installation

Install token instruments so that a token from one section cannot be placed into another instrument at the same station. Ideally, if a token is incorrectly moved, it cannot be placed into the next station's instrument.

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Block section tokens

Consecutive block sections have tokens with configurations A, B, and C. Following sections use the same order. Junction or new crossing stations require special tokens (D and E).

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Block instrument mounting

Block instruments must be mounted level to prevent token issues and tilting.

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Instrument polarity check

After installation, check that the correct polarities are connected to the instruments at both ends before commissioning.

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Mechanical part check

Examine all mechanical components for smooth movement and no jamming.

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Single Line Tokenless Block Instrument Installation

Installation procedures for a block instrument system that doesn't use physical tokens to control train movement.

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Instrument Mounting

Instruments must be mounted level, with easy access and maintenance space.

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Pre-installation Instrument Checks

Checks for mechanical damage, corrosion, panel integrity, and seal integrity prior to installation.

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External Electrical Connections

Measuring insulation resistance between each insulated circuit and Earth in block instruments.

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Block Release Criteria

Block release in a single line tokenless system is achieved by sequentially operating two track circuits.

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Last Stop Signal Operation

The sending station's Last Stop signal cannot be turned off unless receiving station is ready and sending station is ready for train going.

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Line Clear Conditions

To grant a "Line Clear", both reception signals and the Last Stop Signal must be 'ON'.

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Last Stop Signal Maintenance

The Last Stop Signal turns 'ON' when a train enters the block section and remains 'ON' until the train clears, which returns the system to 'Line Closed'.

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Block instrument installation tests

Checks conducted on block instruments during installation to ensure proper functioning.

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Quick acting relays for stick circuits

Not to be used in block instrument stick circuits. Only specific types of relays are allowed (Immunized plug-in 'Q' series, slow AC immunized relays).

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Block release operation

Block release is activated by the sequential operation of two track circuits.

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Commutator handle lock

The commutator handle must be locked before the "Train on Line" indication appears.

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Block Clearance Relay activation

The Block Clearance Relay should activate only after the commutator is in the "Train on Line" position.

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Last Stop Signal, 'OFF' restriction

The Last Stop Signal cannot be taken 'OFF' when the commutator is not in the "Line Clear" position.

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Last Stop Signal automatic 'ON'

Last Stop Signal automatically turns 'ON' when a train enters the block and stays 'ON' until the train reaches the next station and system is cleared.

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Commutator return

The commutator must be freely returnable to 'Line Closed' when turned to 'Train On Line' position.

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Token Census

A periodic review of tokens in block sections, conducted at least every six months, recording all active tokens and any losses or replacements.

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Damaged Tokens

Tokens that are cracked, deformed, or worn below standard size and are thus unsafe to use in the equipment, requiring their removal and replacement.

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Lost Tokens

Tokens that cannot be found after a thorough search, requiring a formal report to the responsible signal engineer, followed by a cancellation notice to all relevant parties.

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Token Replacement (lost)

In cases of a missing token that remains lost for six months, a token with the next higher number in the series will be used instead. The lost original token if found, will be broken and stored.

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Token Register

Official records are kept of all tokens used, those removed, lost or replaced, to accurately track the system's components.

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Joint Certificate

A formal agreement signed by different departments (Signals & Operations) noting a token's loss, ensuring accountability and proper procedures.

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Sectional JE/SSE duties

Signal engineers/supervisors assigned to specific block sections must complete a census of tokens within those areas. This includes keeping and updating record of all tokens, especially regarding those removed or added for replacement.

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Railway Gazette

Formal announcement regarding lost tokens, this ensures all involved personnel are made aware of the missing equipment and any consequences.

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Token Balance Book

A form used to record the transfer of tokens between block instruments. It's filled out by technicians and signed by station masters to verify the exchange.

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Token Instrument Balance

The number of tokens held within a block instrument. When the balance falls below six, the station master must alert the technician by wire or control message.

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Token Instrument Replenishment

The process of adding tokens back into an instrument. This is done when the instrument is in the 'Line Closed' position, meaning the track is clear.

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Token Pouch

A container used to hold tokens, kept in proper repair by the Traffic Department. Damaged pouches are not allowed to be used.

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Bell Signals Importance

Bell signals are still essential even with the presence of telephones. They provide a vital communication backup to ensure safe operation.

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Technician's Fortnightly Check

Every two weeks, the technician must check that electrical & mechanical locks are in good condition and not easily forced.

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Operating Staff Responsibility

The staff operating the block instruments is responsible for their safe working by correctly using the code of bell signals and operating the instruments in the right sequence.

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Token Instrument Installation Rule

Token instruments should be installed in a way that a token from one section cannot be accidentally placed into another instrument at the same station.

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Study Notes

Earthing

  • Separate earth provided for each instrument
  • Earth buried at least 1.5 meters deep
  • Earth at least 2.5 meters from other earths
  • Earth resistance not more than 10 ohms
  • Separate earth for equipment using earth return
  • Earth wire length as short as possible
  • Earth wire diameter at least 4mm
  • Earth wire protected from damage
  • Connections well soldered

Installation of Single Line Token Instruments

  • Token placement prevents one section token from use in another instrument at a station
  • Ideal installation prevents token from being placed in a subsequent station in the event of an overrun
  • Consecutive sections use configurations A, B, and C, followed by repeating those configurations
  • Junction or new crossing stations use configurations D and E
  • Instruments mounted level (using spirit level, if needed)
  • Prevent tokens from tilting or entering incorrect races (specifically for ball and tablet forms of token instruments)

Tests After Installation and Before Commissioning

  • Check connections at both ends
  • Check all moving parts for friction or jamming
  • Ensure commutator changes only when token engages corresponding tracks (for ball and tablet instruments)
  • Check insulation and absence of instrument body/earth leakage on wiring and components

Installation of Single Line Tokenless Block Instruments

  • Instruments mounted level for easy maintenance access
  • Thorough pre-installation check for mechanical damage, corrosion, and secure components (nuts and bolts)
  • Ensure that the front panel (Push Button type instruments, specifically) is free from damage (splitting, warping, etc.)
  • Check that relays and counters are intact, sealed properly
  • Measure insulation resistance between each circuit and earth; minimum 10 mega-ohms
  • Block release sequence controlled by two track circuits

Testing Single Line Tokenless Block Instruments

  • Last Stop Signal at sending station prevents being turned 'OFF' until receiving station is set for "Train Coming From" and sending station set for "Train Going To" situations
  • Line Clear granted only when signals and Last Stop Signal show 'ON'
  • Last Stop Signal remains 'ON' until train clears the block section, then returns to 'Line Closed' and a new 'Line Clear' is issued
  • Opposing signals can't both be turned 'OFF' at the same time
  • Train arrival confirmation is directional
  • Shunting key operation only allowed in "Line Closed" or "Train Going To" conditions

Installation of Double Line Block Instruments

  • Quick acting relays not used in stick circuits (specific type of Q relays required, with minimum 300-msec pick-up time)
  • DC 3-position polarized relays, approved type, used for line circuits in block working
  • Block release sequential, using two track circuits

Installation Tests for Double Line Instruments

  • Commutator needs to be locked, "Train on Line" indication should appear during the commutator movement from "Line Clear" to "Traon on Line"
  • Block Clearance Relay should activate only after commutator changeover.
  • Last Stop signal 'turn OFF' function restricted if commutator not on "Line Clear"
  • Last Stop signal automatically turns 'ON' for trains passing through a block section, remaining 'ON' until "Line Clear" condition achieved.
  • Commutator movement from "Line Closed" to "Train On Line" allows a return to "Line Closed"

Token Instrument Maintenance - General

  • Senior Section Engineer maintains a register of instruments with type, serial number, location, and manufacturer details.
  • Register includes installation and last overhaul dates
  • Record of tokens in or out of service, including lost or damaged devices
  • Sectional JE/SSE performs a census of tokens every 6 months, recording their status and location for safety and proper management.

Damaged Tokens

  • Damaged tokens are replaced by tokens of the same number, and maintenance personnel must be informed
  • Cracked or deformed tokens, as well as those smaller than standard size, must be removed from service and sent to the Stores
  • Maintain records of removed tokens

Lost Tokens

  • Senior staff issues a joint certificate if a token is lost for thorough search, initiating procedures, canceling the lost token, and advising staff in the case that a token has gone missing.
  • Missing tokens remain inactive
  • Six months without finding loss token, create a replacement
  • Lost tokens, even when located later, are broken and stored

Balancing of Tokens

  • Technicians transfer tokens between instruments (when necessary)
  • Token Balance Book (form S&T/TB) used to record these transgers
  • This form is checked by senior personnel
  • Confirmation of the token balance transfer with relevant staff (station master) at both ends for verification and consistency.

Responsibility of Operating Staff

  • Staff responsible for safe equipment operation utilizing the correct signal codes.
  • Proper sequence and use of signals imperative.
  • Bell signals still important, even if other forms of communication exist.

Block Instruments and Ancillary Maintenance

  • Fortnightly inspections ensure proper component function (locks, indicators, contacts, springs, armatures, wiring, terminal screws)
  • Circuits and associated wiring, as well as electrical components, should be routinely inspected for proper function.
  • Indicators and contacts need to be free from pitting and must be operational when triggered.

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Related Documents

Chapter 18: Block Instruments, Section 5-8 (PDF)

Description

This quiz covers essential standards for earthing separate to each instrument, including specifications for earth depth, resistance, and wire regulations. Additionally, it addresses the installation protocols for single line token instruments, focusing on token placement and configuration requirements. Test your knowledge on these critical safety and installation practices.

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