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Questions and Answers
It is recommended to leave 25% or more conductors spare for cables carrying 5 or more pairs of conductors.
True
The desired cable route should be determined without physically examining the track.
False
Telecom cables should be laid at least 5 meters away from the nearest track.
False
Cable markers should be placed at intervals of 100 meters along the cable route.
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All trenches made for laying cables must be filled up and rammed properly before sunset on the same day.
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It is acceptable for telecom cables to be laid without consultation with P.Way staff if trenches are closer to the formation area of the track.
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The quad cable RCC route marker should be painted blue as specified in the drawing.
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It is preferable to chart the cable route on a plan that indicates existing routes of power cables.
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The distance between the cable and the OHE mast must be at least 1 meter when the cable trench is limited to 0.5 m due to local conditions.
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Cables must be laid with a minimum depth of 2 meters below the surface of the ground.
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In the vicinity of traction substations, cables should be laid at least five meters away from any metallic body fixed in the ground.
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When laying cables parallel to the track, the recommended burial depth is 1.5 meters.
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Cables laid near OHEs should maintain a distance of at least 3 meters from the nearest edge of the cable trench to the OHE mast when the trench depth exceeds 0.5 m.
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HT and LT power cables are permitted to be laid in the same trench as telecommunication cables.
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When laying signalling and telecommunication cables in the same trench, bricks should be placed at intervals of 1 meter.
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Cables laid across the track must be buried at a depth of one meter below the rail flanges.
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The bending radius for aluminum sheathed armoured cables must not be less than 50 times the diameter of the cable.
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OFC and quad cables are generally laid in separate trenches.
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Telecom cables should typically be laid within 2 meters inside the Railway boundary.
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Cable markers along the route should be provided at regular intervals of 50 meters.
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It is advisable to leave 10% or more conductors spare for cables carrying 5 or more pairs.
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Trenches in areas closer to the track should be made without consulting P.Way staff.
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Cable markers should be painted in green color as per the specified drawing.
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Important points like cable joints should not require additional markers.
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The actual route for laying cables should be decided by travelling or walking along the track.
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The desired cable route plan should indicate various road and track crossings.
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The distance between the cable and the OHE mast can be reduced to 0.5 m if the cable is laid in concrete pipes.
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Cables must be laid at a depth of at least 2 meters for safety purposes.
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Cables installed in areas close to traction substations should maintain a distance of at least 3 meters from any metallic body.
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When laying cables across the track, they must be one meter below the rail flanges.
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A distance of 10 meters should be maintained from the center of the nearest track when laying cables outside station limits.
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Telecommunication cables can be laid in the same trench as HT power cables without any restrictions.
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Cables should be subjected to sharp bends during laying to optimize the installation process.
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OFC and quad cables are typically laid in different trenches as per guidelines.
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The bending radius for aluminum sheathed armoured cables should not be less than 40 times the diameter of the cable.
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When cables are laid in the vicinity of OHE switching stations, a distance of at least 5 meters should be maintained from the station earthing.
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It is desirable to leave 25% or more conductors spare for all cables carrying 5 or more pairs of conductors.
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Cables should be laid at least 2 meters away from the nearest track.
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Cable markers should be provided at intervals of 100 meters along the route.
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The actual cable route must be decided without physically examining the track.
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Telecom cables should normally be laid within 1 meter inside the Railway boundary.
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Trenches in or nearer to the formation area of track can be made without consultation with P.Way staff.
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Cable markers should be painted red as specified in the drawing.
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The distance between the cable and the nearest electrical power cable is advised to be at least 1 meter.
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Cables must be laid at least 1 meter below the surface of the ground.
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The nearest edge of the cable trench must be at least 2 meters away from the OHE mast.
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Cables laid across the track must be buried one meter below the rail flanges.
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A minimum of 5 meters must be maintained between the cable and station earthing near OHE switching stations.
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Telecommunication cables can be laid in the same trench as HT and LT power cables.
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When cables are laid in the vicinity of traction sub-stations, they should be at least one meter away from any metallic body.
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Cables laid parallel to the track should be buried deeper than those laid across the track.
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Bricks should be placed every two meters to maintain a distance between signalling and telecommunication cables when laid in the same trench.
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Cables should not be subjected to any sharp bends during laying.
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The distance between the cable and any independent earth provided for an OHE structure can be reduced to 0.5 m.
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Study Notes
Cable Planning and Laying
- Cable Type and Quantity: Determine the number of conductors, size, and type of cable (quad/PIJF) required for the desired circuits. The Zonal Railway typically allocates quad on the 6Q, including BPAC/IBS.
- Spare Conductors: Include 25% or more spare conductors for future expansion in cables containing 5 or more pairs. This accounts for the long lifespan of these cables.
- Route Planning: Determine the best route by walking along the track and considering factors like alignment, road and track crossings, power cables, water and sewage mains, and other important features.
- Route Documentation: Document the chosen route on a route plan, outlining the track alignment, offsets from permanent structures, and other relevant features.
- Distribution Points: Choose convenient locations for distributing the main cable to smaller cables for subscriber installations (for exchanges) or emergency socket placements (for emergency communication).
- Cable Placement: Telecom cables should typically be laid within 1 meter of the railway boundary as designated by boundary pillars or, where these are absent, by railway P.Way/works officials. Maintain a minimum distance of 2 meters from the nearest track and beyond the embankment. Trenches near the track formation should only be dug with P.Way staff consent and be properly filled and rammed before sunset on the same day, especially during the monsoon season and humid soil.
- Cable Separation: Ensure a minimum separation of 1 meter between telecom cables and adjacent electrical power cables.
- Cable Markers: Install markers at 50-meter intervals along the route, with additional markers to indicate cable joints, water/sewage mains, power cables, crossings, bends, or curves. Quad cable route markers should adhere to Drawing no. RDSO/TCDO/COP-22(a) found in Chapter XIII. Color the markers red as specified in said drawing. Additionally, use yellow enamel paint on all sides of the RCC marker above ground to easily identify quad joints.
- Cable Depth: Bury the cable at least 1 meter below the ground surface. Ensure the trench is wide enough for smooth cleaning and cable laying.
- OHE Considerations: In yards or locations with limited trench depth (0.5 meters), cables should be maintained 1 meter away from OHE masts to prevent contact with high-tension conductors. Where this creates challenges, use concrete pipes for the cable, allowing a reduced distance of 0.5 meters.
- OHE Mast Depth: When trench depth exceeds 0.5 meters near OHE masts, the nearest edge of the trench should be at least 3 meters from the OHE mast.
- Joint Marker Placement: Mark cable joint locations by painting an approved legend on the nearest OHE mast.
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Traction Substations and OHE Switching Stations:
- Maintain a 1-meter distance between cables and any metallic grounding components within traction substations. Encase the cable in concrete pipes or brick channels within 300 meters on either side of the substation. Preferably locate the cable on the side of the track opposite the substation.
- Ensure a 1-meter distance between cables and metallic grounding components within OHE switching stations. Maintain a 5-meter distance from station earthing, which can be reduced to 1 meter if the cable is laid in concrete piles.
- For independent earthing provided for an OHE structure, keep the cables at least 1 meter away from the earthing.
- Standard Cable Distance: Outside station limits, cables are generally laid at a standard distance of 10 meters from the center of the nearest track.
- Signaling and Telecommunication Cables: When laying signaling and telecommunication cables in the same trench, maintain a 100-millimeter distance between them by placing bricks at 2-meter intervals.
- Power and Telecommunication Cable Separation: Do not lay HT and LT power cables in the same trench as telecommunication cables.
- Track Cable Depth: Cables parallel to tracks should be buried 1 meter below the ground surface, while cables crossing tracks must be 1 meter below the rail flanges.
- Cable Trench Separation: Keep telecommunication cable trenches as far away as possible from power cable trenches.
- Specific Cable Laying: Follow approved methods for laying cables along girder bridges, over culverts, through culvert beds, over rocky terrain, and other specialized locations.
- Cable Bending: Avoid sharp bends while laying. The bending radius for cables should never be less than 40 times the cable diameter for aluminum sheathed armored cables.
- OFC and Quad Cable Laying: Typically, OFC and quad cables are laid in the same trench. Chapter XIII provides relevant drawings and specifications for this.
Planning Cable Routing
- When planning cable routes, determine the number, size, and type of conductors first.
- Aim for 25% or more spare conductors for cables with 5+ pairs for future expansion.
- Walk the track route to determine the best alignment for cable placement.
- Create a route plan showing the alignment, offsets, and crossings with other utilities.
- Select convenient locations for cable distribution (main to smaller distribution cables).
- Telecommunication cables should be laid within 1 meter of the railway boundary.
- Lay the cables at least 2 meters away from the nearest track and beyond the embankment.
- Consult with P.Way staff before trenching in or near the track formation area.
- Ensure trenches are filled and rammed properly after cable installation before sunset.
- Use appropriate care during monsoon season and in alluvial soil.
- Separate telecom cables from electrical power cables by at least 1 meter.
Marking Cable Routes
- Use cable markers along the route at intervals of 50 meters.
- Provide additional markers for key points like joints, mains, crossings, and bends.
- Use Quad cable RCC route markers as per RDSO/TCDO/COP-22(a).
- Paint markers red as specified in the drawing.
- Mark Quad cable joints with yellow enamel paint on all sides of the marker.
Cable Depth and Spacing
- Bury cables at least 1 meter below the ground surface.
- Make trenches wide enough for cleaning and cable laying.
- Maintain a minimum distance of 1 meter between cables and overhead equipment (OHE) masts when limited to 0.5 meters depth (due to local conditions).
- Lay cables in concrete pipes to reduce the minimum distance to 0.5 meters in these specific cases.
- Ensure the nearest edge of the cable trench is at least 3 meters away from OHE masts when trench depth is greater than 0.5 meters.
Locations Near Power Sources
- Near traction sub-stations, lay cables at least 1 meter from any metallic body fixed in the ground.
- Keep a 1 meter distance from sub-station earthing.
- Enclose cables in concrete pipes or brick channels for 300 meters on each side of the sub-station.
- Prioritize laying cables on the side of the track opposite the sub-station.
- Near OHE switching stations, lay cables at least 1 meter from any metallic body fixed in the ground.
- Maintain a 5 meter distance from station earthing, reducing to 1 meter if cables are laid in concrete piles.
- Lay cables at least 1 meter away from any independent earthing provided for OHE structures.
General Cable Placement Rules
- Outside station limits, lay the cable a standard distance of 10 meters from the track center.
- Keep a 100 mm distance between signaling and telecommunication cables by placing bricks between them at intervals of two meters.
- Do not lay high and low tension power cables with telecommunication cables in the same trench.
- Bury cables parallel to the track at a depth of 1.0 meter.
- Bury cables crossing the track at a depth of 1 meter below the rail flanges.
- Keep the trenches for telecommunication cables as far away as possible from power cable trenches.
Special Cable Laying Scenarios
- Follow approved methods for specific locations like girder bridges, culverts, rocky terrain, etc.
- Avoid sharp bends. The minimum bending radius for aluminum sheathed armored cables is 40 times the cable diameter.
- OFC and quad cables are typically laid in the same trench. Refer to chapter XIII for relevant drawings.
Cable Planning and Routing
- Determine the number, size, and type of conductors required based on the circuit configuration.
- For cables carrying 5 or more conductor pairs, it's recommended to leave at least 25% of conductors spare for future expansion due to their long lifespan.
- Choose a route along the track, considering the best alignment and noting any crossings, water/sewage mains, and other important points.
- Document the chosen route on a plan including existing power cable routes.
- Identify convenient distribution points for smaller distribution cables in case of subscriber cabling or emergency sockets.
- Lay telecommunication cables within 1 meter of the railway boundary, 2 meters away from the nearest track and beyond the embankment.
- Ensure that the cable is separated by at least 1 meter from electrical power cables.
- Utilize cable markers every 50 meters, with additional markers for important points, such as cable joints, water and sewage mains, power cables, crossings, and bends.
- The quad cable RCC route marker should follow Drawing no. RDSO/TCDO/COP-22(a) and be painted red.
- Mark quad joints using yellow enamel paint on all sides of the RCC cable marker above ground.
- Typically bury cables at least 1 meter below ground level.
- In yards or areas with limited trench depth (0.5m), maintain a 1 meter distance between the cable and the OHE mast or other structures.
- When the cable trench depth exceeds 0.5 meters near OHE masts, ensure the nearest edge of the trench is at least 3 meters away from the mast.
- Note the position of cable joints on the nearest OHE mast using an approved legend.
Cable Laying Guidelines in Specific Locations
- In the vicinity of traction substations, lay cables at least 1 meter away from ground-fixed metallic bodies and substation earthing. Utilize concrete pipes or brick channels for a 300-meter length on either side of the substation.
- Near OHE switching stations, lay cables at least 1 meter away from any metallic bodies and at least 5 meters away from station earthing.
- When an independent earth is provided for an OHE structure, lay cables at least 1 meter away from such earthing.
- Outside station limits, lay cables at a standard distance of 10 meters from the center of the nearest track.
- When laying signalling and telecommunication cables in the same trench, maintain a distance of around 100 mm between them using bricks at 2-meter intervals.
- Separate HT and LT power cables from telecommunication cables; do not lay them in the same trench.
- Typically bury cables parallel to the track at 1 meter depth.
- Bury cables crossing the track at 1 meter below the rail flanges.
- Ensure the telecommunication cable trench is as far as possible from the power cable trench.
- Lay cables along girder bridges, culverts, rocky terrain, etc., according to approved methods for each location.
- Avoid sharp bends when laying cables, ensuring the bending radius is at least 40 times the cable diameter for aluminum sheathed armored cables.
- OFC and quad cables can typically be laid in the same trench.
### Cable Laying References
- Consult Chapter XIII of the Indian Railways Telecom Manual for drawing information on OFC/quad cable laying.
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Description
This quiz covers essential aspects of cable planning and laying, including cable type selection, route planning, and documentation. It emphasizes the importance of spare conductors and distribution points for effective communication infrastructures. Test your knowledge on these critical components of railway cable management.
