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What is the minimum safe distance a person is allowed to approach live parts of the O.H.E under normal conditions?
What is the minimum safe distance a person is allowed to approach live parts of the O.H.E under normal conditions?
What protective measure should be adopted if a part of a signal post falls within 2 meters of a 25 KV live conductor?
What protective measure should be adopted if a part of a signal post falls within 2 meters of a 25 KV live conductor?
What should be provided if it is impracticable to install protective iron screening near a live conductor?
What should be provided if it is impracticable to install protective iron screening near a live conductor?
Where should signals normally be located in relation to the track?
Where should signals normally be located in relation to the track?
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What is the minimum distance required between the traction mast and the signal post if the mast is located in front of the signal?
What is the minimum distance required between the traction mast and the signal post if the mast is located in front of the signal?
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If using offset brackets for signals, what should not be affected?
If using offset brackets for signals, what should not be affected?
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Who is responsible for explaining and ensuring compliance with safety instructions to the signal staff?
Who is responsible for explaining and ensuring compliance with safety instructions to the signal staff?
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What should be done to achieve adequate visibility of signals in exceptional cases?
What should be done to achieve adequate visibility of signals in exceptional cases?
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What is the maximum distance allowed between two consecutive insulators on the same rod?
What is the maximum distance allowed between two consecutive insulators on the same rod?
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What is the minimum clearance required between the top of the rod crossing the track and the bottom of the rail?
What is the minimum clearance required between the top of the rod crossing the track and the bottom of the rail?
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Which element must be electrically isolated from the track?
Which element must be electrically isolated from the track?
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What distance must be maintained between the operating rod and the O.H.E mast?
What distance must be maintained between the operating rod and the O.H.E mast?
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Why should additional insulators be provided when the distance between two insulators exceeds 300 meters?
Why should additional insulators be provided when the distance between two insulators exceeds 300 meters?
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What must be done when the Engineering department provides the point lever or point box?
What must be done when the Engineering department provides the point lever or point box?
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Which of the following is NOT a precaution for staff working on Signal & Telecommunication equipment?
Which of the following is NOT a precaution for staff working on Signal & Telecommunication equipment?
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When sections are provided with 25 KV A.C traction, which condition poses a risk to railway personnel?
When sections are provided with 25 KV A.C traction, which condition poses a risk to railway personnel?
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What is the maximum permissible induced voltage for human safety in DC Circuits on Line Relays using unscreened cable?
What is the maximum permissible induced voltage for human safety in DC Circuits on Line Relays using unscreened cable?
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What is the maximum permitted length of direct feed for a single track using unscreened cable?
What is the maximum permitted length of direct feed for a single track using unscreened cable?
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If a signal is located further than the prescribed limits, what method should be used to feed the signal?
If a signal is located further than the prescribed limits, what method should be used to feed the signal?
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What factors must be considered when ensuring the circuit's voltage is inadequate to illuminate the lamps?
What factors must be considered when ensuring the circuit's voltage is inadequate to illuminate the lamps?
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How does the maximum allowed distance for double track compare to that for single track using unscreened cable?
How does the maximum allowed distance for double track compare to that for single track using unscreened cable?
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What type of signal feed system is prescribed?
What type of signal feed system is prescribed?
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What should be done if the signal cannot be fed directly within the prescribed distance?
What should be done if the signal cannot be fed directly within the prescribed distance?
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What color are the cable terminals that indicate danger to maintenance staff?
What color are the cable terminals that indicate danger to maintenance staff?
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What is the factor of safety considered for human safety in these circuits?
What is the factor of safety considered for human safety in these circuits?
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Which of the following safety precautions should staff take before working on Signalling/Telecommunication cables?
Which of the following safety precautions should staff take before working on Signalling/Telecommunication cables?
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What type of tools should staff be equipped with when working on electrical circuits?
What type of tools should staff be equipped with when working on electrical circuits?
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What is one method for treating electric shock victims that should be familiar to the staff?
What is one method for treating electric shock victims that should be familiar to the staff?
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What should staff do if they receive news of a break in the catenary/contact wire?
What should staff do if they receive news of a break in the catenary/contact wire?
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Which of the following is NOT a protective item recommended for staff working on electrical circuits?
Which of the following is NOT a protective item recommended for staff working on electrical circuits?
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What is the purpose of establishing a low resistance electrical connection before cutting cables?
What is the purpose of establishing a low resistance electrical connection before cutting cables?
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What action should be taken if any abnormal working of the signalling equipment is noticed?
What action should be taken if any abnormal working of the signalling equipment is noticed?
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What should be displayed in SSEs/JEs (Signal) offices for staff awareness?
What should be displayed in SSEs/JEs (Signal) offices for staff awareness?
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Who is responsible for submitting the Certificate that everything is working correctly after an abnormality?
Who is responsible for submitting the Certificate that everything is working correctly after an abnormality?
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What is one of the key components to be checked before the issue of a certificate for 2.2 KV charging?
What is one of the key components to be checked before the issue of a certificate for 2.2 KV charging?
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What is the minimum distance that signal posts or fittings must be from the live conductor?
What is the minimum distance that signal posts or fittings must be from the live conductor?
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What is required in addition to the replacement of existing relays before issuing a certificate for 2.2 KV charging?
What is required in addition to the replacement of existing relays before issuing a certificate for 2.2 KV charging?
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What must be done to overhead track crossings of BSNL and Railway concerning 2.2 KV anti-theft energisation?
What must be done to overhead track crossings of BSNL and Railway concerning 2.2 KV anti-theft energisation?
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Who is responsible for ensuring compliance with the issued checklist before the OHE is charged at 25 KV?
Who is responsible for ensuring compliance with the issued checklist before the OHE is charged at 25 KV?
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What type of tools should be supplied to maintenance staff as part of the 2.2 KV charging preparations?
What type of tools should be supplied to maintenance staff as part of the 2.2 KV charging preparations?
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What is the minimum setting of masts for colour light signals without route indicators located up to 80 m from the signal?
What is the minimum setting of masts for colour light signals without route indicators located up to 80 m from the signal?
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For colour light signals with horizontal route indicators, what is the minimum height of masts for distances beyond and up to 125 m?
For colour light signals with horizontal route indicators, what is the minimum height of masts for distances beyond and up to 125 m?
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Which of the following is a requirement for masts near signals without route indicators?
Which of the following is a requirement for masts near signals without route indicators?
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What is the minimum height for masts at a distance beyond and up to 210 m for colour light signals with other than horizontal route indicators?
What is the minimum height for masts at a distance beyond and up to 210 m for colour light signals with other than horizontal route indicators?
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What settings should be observed for masts before colour light signals with route indicators?
What settings should be observed for masts before colour light signals with route indicators?
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Which of the following is NOT a requirement for signals without route indicators?
Which of the following is NOT a requirement for signals without route indicators?
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What height is required for masts at a distance beyond and up to 170 m for colour light signals with horizontal route indicators?
What height is required for masts at a distance beyond and up to 170 m for colour light signals with horizontal route indicators?
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What is the minimum height for masts before colour light signals located outside all tracks, provided no approach signal is present?
What is the minimum height for masts before colour light signals located outside all tracks, provided no approach signal is present?
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Study Notes
Requirements of Signalling in 25 KV AC Electrified Area
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Objectives: Ensure signalling equipment functions normally in the presence of traction current, avoid interference from the traction system imperilling train operation, and safeguard equipment/personnel from electric shock.
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Factors Affecting Signalling: Visibility of signals due to overhead line equipment (OHE) structures, electrical clearances of signals in proximity to live OHE, traction return current, and electrostatic/electromagnetic induction.
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Visibility of Signals: Proper OHE implantation during design is crucial. Protective wire-mesh screens should be provided where clearance is <2 meters from live OHE conductors. Approved layout plans for OHE are essential.
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OHE Bonds: Electrical department should install OHE structural, longitudinal, and cross bonds for proper field equipment functioning, especially where needed for sections of track, masts and rails under positive rail track circuits.
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Electrostatic Induction: Eliminate this issue by connecting the signalling circuit to underground cables with a metal sheath.
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Electromagnetic Induction: Causes currents and voltages to occur in parallel conductors (rails, return conductors, and signalling/communications circuits), creating potential differences. Factors like length of parallel conductors, soil conductivity, and shielding affect induced voltage.
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Signal Structure in Electrified Areas: Colour light signals are recommended. Signals must maintain minimum clearance from live OHE parts.
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Broad Gauge Signal Clearances: Illustrations and diagrams (e.g., Drg. No. 22-D1, 22-D2) dictate signal placement to maximize visibility, considering tangent tracks and tracks with varied super elevation.
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Safety Considerations: No personnel should approach closer than 2 meters from live OHE parts. Protective measures like iron screening or caution boards on signal posts (3m above rail) are needed where physical barriers can't be implemented.
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Signal Height and Location: Contact wire is typically 5.60 meters high; catenary height is 7.05 meters. Tunnels/bridges may necessitate lower clearances. Signal placement should consider obstructions. Drawings (e.g., 22-D4, 22-D5) provide specific location details and height constraints where relevant. Masts near signals necessitate specific guidelines to avoid obstructions and poor visibility.
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Signal Circuits: Aerial circuits should generally be avoided within electrified areas. Block instrument circuits are an exception, and their design must be properly protected. Using a separate, protected battery system in the location/cabin is required for equipment requiring it. This includes luminous indicators, telephone relays, electrical locks, door coils, and other components.
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Location of Neutral Sections: Neutral sections should be on tangent tracks and well away from stop signals, ensuring sufficient distance for safe train speed after stopping.
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Outdoor Signalling Circuits: Circuit length must be limited to ensure that induced voltages don't exceed 400V. Wiring must be appropriately sectionalized.
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Signal Feeding Distance: Should not exceed prescribed distance limits. Local/remote feeding options may be used where the distance exceeds the limit.
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Point Operation and Detection: Point operation can be electric or mechanical (with restrictions). Maintenance staff safety must be considered, and the correct procedures should be adhered to.
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Rod Runs and Insulation: Point rods in AC areas require insulated components between sections (e.g., insulated rod joints) because of induced voltage potential.
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Protection of Staff: Rules are provided for personnel working on signalling and telecommunication equipment in electrified areas, especially concerning proximity to, or contact with energized conductors, circuits, and equipment.
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Description
This quiz focuses on the requirements and factors affecting signalling in 25 KV AC electrified areas. It covers objectives such as ensuring the functionality of signalling equipment, avoiding interference, and providing visibility despite overhead line equipment. Participants will learn about protective measures and the role of electrical bonds.
