Podcast
Questions and Answers
The number of conductors and sizes should be determined depending upon the type of ______ desired.
circuits
It is generally desirable to leave 25% or more conductors ______ for future expansions.
spare
The actual route for taking the cables should be decided upon by ______ along the track.
travelling
The desired route should be shown clearly on a ______ plan.
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The telecom cables should normally be laid within 1 meter inside the Railway ______.
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Cable markers shall be provided at a nominal interval of ______ m.
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The Quad cable RCC route marker shall be as per Drawing no. ______.
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The cable should be laid at least ______ m away from the nearest track.
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The cable shall be at least ______ m below the surface of the ground.
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In exceptional cases, a minimum distance of one meter shall be maintained between the cable and the ______ mast.
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The position of cable joints shall be marked on the nearest OHE mast by painting of an approved ______.
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Cables should be laid in ______ pipes or enclosed brick channels for a length of 300 m on either side of the sub-station.
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In the vicinity of traction sub-stations, the cable shall be laid at least ______ meter away from any metallic body.
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When signalling and telecommunication cables are laid in the same trench, a distance of about ______ mm is to be maintained between them.
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The cable laid parallel to the track shall normally be buried at the depth of ______ m.
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When cables are to be laid along the girder bridges, they shall be laid as per the approved ______ for each such location.
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The trench for telecommunication cables shall be kept as far away as possible from the trench for the ______ cables.
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The bending radius for the cable shall in no case be less than ______ times the diameter of the cable.
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The cable shall be laid at least ______ m below the surface of the ground.
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In exceptional cases, a minimum distance of one meter shall be maintained between the cable and the ______ mast.
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Position of cable joints shall be marked on the nearest OHE mast by painting of an approved ______.
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In the vicinity of traction sub-stations, the cable shall be laid at least one meter away from any ______ body fixed in the ground.
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Cables should be laid in ______ pipes or enclosed brick channels for a length of 300 m on either side of the sub-station.
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When cables are laid in the same trench, a distance of about ______ mm is to be maintained between them.
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The trench for telecommunication cables shall be kept as far away as possible from the trench for the ______ cables.
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The cable laid parallel to the track shall normally be buried at a depth of ______ m.
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When cables are to be laid along girder bridges, the laying shall be done as per the approved ______ for each such location.
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The nearest edge of the cable trench must be at least ______ m away from the OHE mast.
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The cable route should indicate various road and track ______.
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After deciding on the route, convenient points for ______ should be chosen.
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Cable markers shall be provided at a nominal ______ of 50 m.
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The desired route should be charted on a route plan showing the actual ______ of the track.
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The telecom cables should be laid at least 2 m away from the nearest ______.
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Trenches in or nearer to the formation area of track shall be made only after consultation with ______ staff.
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In rainy seasons, special care shall be ensured during the ______ season.
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The cable should be laid at least 1 m away from the nearest electrical ______ cable.
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Allocation of quad may be issued by the Zonal Railway on the _____.
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The cable route should be shown on a route plan indicating the actual alignment of the _____.
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Convenient points for distribution should be chosen after deciding on the _____.
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The telecom cables should be laid within 1 meter inside the Railway _____.
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Cable markers shall be provided at a nominal interval of _____ m.
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It is preferable to chart the route on a route plan where existing routes of power ____ are shown.
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Special care must be ensured during the _____ season.
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It shall also be ensured that the cable is separated by at least 1 m from the nearest electrical power _____.
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The cable shall be at least ______ m below the surface of the ground.
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In exceptional cases, a minimum distance of one meter shall be maintained between the cable and the ______ mast.
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When the depth of the cable trench is limited to 0.5 m, the distance can be brought down to ______ m.
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The position of cable joints shall be marked on the nearest OHE mast by painting of an approved ______.
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Cables should be laid in concrete ______ or enclosed brick channels for a length of 300 m on either side of the sub-station.
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In the vicinity of traction sub-stations, the cable shall be laid at least one meter away from any metallic ______ of the sub-station.
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When signalling and telecommunication cables are laid in the same trench, a distance of about ______ mm is to be maintained between them.
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The trench for the telecommunication cable shall be kept as far away as possible from the trench for the ______ cables.
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The bending radius for the cable shall in no case be less than ______ times the diameter of the cable.
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The cable laid parallel to the track shall normally be buried at the depth of ______ m.
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Study Notes
Planning for Cable Laying on Railway Routes
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Cable Types and Conductor Requirements:
- Determine the number, size, and type (quad, PIJF) of conductors needed based on the desired circuit types.
- The Zonal Railway may allocate quad cables, including BPAC/IBS.
- Leave at least 25% spare conductors for future expansion in cables with 5 or more pairs.
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Route Planning:
- Choose the cable route by physically walking the track and identifying the most suitable alignment.
- Create a route plan showing the alignment, offsets from permanent structures, and crossings (road, track, power cables, water/sewage mains).
- Ideally, overlay the plan with existing power cable routes.
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Distribution Points:
- Decide on locations for cable distribution points (e.g., main to smaller cables for subscriber connections, emergency socket locations).
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Cable Location and Depth:
- Lay telecom cables within 1 meter of the railway boundary, referencing boundary pillars or seeking assistance from P.Way officials.
- Maintain a 2-meter distance from the track and beyond the embankment.
- Trenches in or near the track formation require P.Way consultation and must be filled and rammed the same day before sunset, especially during monsoon or in alluvial soil.
- Keep cables at least 1 meter away from electrical power cables.
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Cable Markers:
- Install markers at 50-meter intervals and at key locations (joints, crossings, bends, water/sewage mains, power cable).
- Use Quad cable RCC route markers as per Drawing no. RDSO/TCDO/COP-22(a) (Chapter XIII).
- Paint markers red and add yellow enamel to Quad joints for easy identification.
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Cable Trench Width and Depth:
- Bury cables at least 1 meter below ground.
- Ensure sufficient trench width for easy cleaning and cable laying.
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Safety Precautions Near Overhead Electrical Equipment (OHE):
- Maintain a minimum 1-meter distance between cables and OHE masts.
- If this is not possible, lay cables in concrete pipes, reducing the distance to 0.5 meters.
- When the cable trench depth exceeds 0.5 meters, maintain a 3-meter distance between the trench edge and the OHE mast.
- Mark cable joint locations on the nearest OHE mast with an approved legend.
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Laying Cable Near Traction Substations and OHE Switching Stations:
- Lay cables at least 1 meter from metallic bodies of substations and substation earthing.
- Enclose cables in concrete pipes or brick channels for 300 meters on either side of the substation.
- Ideally, lay cables on the track side opposite the substation.
- For OHE switching stations, maintain 1 meter from metallic bodies and 5 meters from station earthing, or use concrete piles to reduce this distance to 1 meter.
- Lay cables at least 1 meter away from any independent earth provided for OHE structures.
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General Cable Layout Practices:
- Outside station limits, lay cables at a standard distance of 10 meters from the track center.
- When laying signalling and telecommunication cables in the same trench, maintain a 100 mm gap using bricks at 2-meter intervals.
- Never lay HT/LT power cables and telecommunication cables in the same trench.
- Bury cables parallel to the track at 1 meter deep, and 1 meter below rail flanges when crossing the track.
- Keep power and telecommunication cable trenches as far apart as possible.
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Special Cable Laying Scenarios:
- Lay cables along girder bridges, culverts, rocky terrain, etc., according to specific approved methods for each location.
- Avoid sharp bends in cables, ensuring a bending radius of at least 40 times the cable diameter for aluminum sheathed armored cables.
- Normally lay OFC and quad cables in the same trench. Refer to Chapter XIII for specific drawings.
Planning Cable Routes
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Planning stage:
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Determine the number and types of conductors needed
- Consider the type of circuits required (e.g., quad/PIJF)
- Zonal Railway allocates quad cables
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Allow for future expansion:
- Plan for at least 25% spare conductors for cables carrying 5+ pairs
- Consider the long life expectancy of telecommunication cables
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Determine the number and types of conductors needed
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Route Selection:
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Walk the route:
- Identify the optimal alignment for the cable route
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Document the route:
- Produce a detailed route plan, including:
- The actual alignment of the track
- Offsets from permanent structures and track
- Locations of road/track crossings
- Crossings with power cables, water/sewage mains
- Other points of importance
- Existing routes of power and telecom cables
- Produce a detailed route plan, including:
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Walk the route:
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Distribution points:
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Locate convenient points for distribution:
- For subscriber cabling, use a main cable to connect to smaller distribution cables
- For emergency communication, consider the placement of emergency sockets
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Locate convenient points for distribution:
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Cable Placement:
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Telecom cables should be within 1 meter of the railway boundary:
- Use boundary pillars as reference points
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Minimum distances from railway infrastructure:
- At least 2 meters away from the nearest track
- Outside the track embankment
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Trenches near the track require P. Way consultation:
- Fill and compact the trench on the same day before sunset
- Take extra precaution during the monsoon and alluvial soil
- Maintain a 1-meter separation from electrical power cables
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Cable Markers:
- Install markers at 50-meter intervals
- Use additional markers for:
- Cable joints
- Water and sewage mains
- Power cables
- Crossings
- Alignment bends/curves
- Use Drawing no. RDSO/TCDO/COP-22(a) for the Quad cable RCC route marker
- Paint the marker red as per the specified drawing
- Paint the Quad joint with yellow enamel on all sides
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Depth of Cable:
- Standard depth: 1 meter below the surface
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Exceptional cases:
- Yards and limited trench depth (0.5 meters)
- Minimum 1-meter distance from OHE mast and other potential contact points
- Lay the cable in concrete pipes to reduce the minimum distance to 0.5 meters
- Trench depth exceeding 0.5 meters near OHE masts
- The nearest edge of the trench must be at least 3 meters away from the OHE mast
- Yards and limited trench depth (0.5 meters)
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OHE Mast Marking:
- Mark the location of cable joints on the nearest OHE mast using an approved legend
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Vicinity of Traction Substations, OHE Switching Stations, and Earthing Systems:
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Substations:
- At least 1 meter from the metallic body of the substation fixed in the ground
- At least 1 meter away from the substation earthing
- Lay cables in concrete pipes or brick channels for 300 meters on either side of the substation
- Preferably on the track side opposite the substation
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OHE Switching Stations:
- At least 1 meter from the metallic body fixed in the ground
- At least 5 meters away from the station earthing
- Can reduce the distance to 1 meter if the cables are laid in concrete piles
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Independent Earthing for OHE Structures:
- At least 1 meter from the earthing
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Substations:
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Outside Station Limits:
- Standard distance of 10 meters away from the center of the nearest track
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Signalling and Telecommunication Cables in the Same Trench:
- Maintain a 100 mm distance between cables by placing bricks every 2 meters
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HT and LT Power Cables and Telecommunication Cables:
- Do not lay in the same trench
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Depth of Cable Relative to Track:
- Cables running parallel to the track should be at least 1 meter below the ground
- Cables crossing the track should be at least 1 meter below the rail flanges
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Spacing Between Power and Telecommunication Cable Trenches:
- Maximum separation between the trenches
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Laying Cables Over Bridges, Culverts, Rocky Terrain:
- Lay cables according to approved methods for each location
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Avoiding Sharp Bends:
- The bending radius must be at least 40 times the cable diameter for aluminium sheathed armoured cables
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Laying OFC and Quad Cables:
- Normally laid together in the same trench
- Refer to Chapter XIII for drawings and specifications
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Telecom cables should be within 1 meter of the railway boundary:
Cable Planning and Laying
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Initial Considerations: Begin by determining the number and sizes of conductors, as well as the type of cable required (quad/PIJF), based on the desired circuit types.
-
Spare Conductors: Generally, allocate 25% or more spare conductors for cables with 5 or more pairs to accommodate future expansions. This is important due to the long service life of these cables.
-
Route Selection:
- Choose the optimal cable route by physically traversing the track area.
- Clearly depict the chosen route on a plan, showing the track alignment, offsets from permanent structures, and crossings (roads, tracks, power cables, utilities).
- Utilize existing plans that show locations of other cables.
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Distribution Points:
- Identify convenient locations for distributing main cables to smaller cables (e.g., subscriber cabling, emergency sockets) to optimize network connectivity.
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Cable Placement:
- Typically, telecom cables are laid within 1 meter of the railway boundary, referencing boundary pillars.
- Place cables at least 2 meters away from the nearest track and beyond the embankment.
- Trenches within or near the track formation should only be made after consulting with P.Way staff.
- Fill and compact trenches after laying cables before sunset, especially during monsoon season or in alluvial soil.
- Maintain at least 1 meter separation from electrical power cables.
-
Cable Marking:
- Install markers along the entire route at 50-meter intervals.
- Provide additional markers for key locations like cable joints, utilities, crossings, bends, and curves.
- Use approved markers (e.g., Drawing no. RDSO/TCDO/COP-22(a)) and paint them as specified.
- Mark quad cable joints with yellow enamel paint on the markers above ground.
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Cable Depth:
- Bury cables at least 1 meter below the ground surface.
- Trench width should allow for smooth cleaning and cable laying.
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Special Considerations:
- In limited depth situations (e.g., yards, 0.5 meter depth), maintain at least 1 meter separation between cables and overhead line (OHE) masts or other structures.
- Lay cables in concrete pipes when the 1-meter separation is difficult to maintain.
- When trench depth exceeds 0.5 meter near OHE masts, keep the nearest edge of the trench at least 3 meters away from the mast.
- Mark the position of cable joints on the nearby OHE mast with an approved legend.
-
Substations and Switching Stations:
- Near traction substations:
- Lay cables at least 1 meter away from grounded metallic substation components and substation earthing.
- Place cables in concrete pipes or brick channels for 300 meters on either side of the substation.
- Route cables on the side of the track opposite the substation.
- Near OHE switching stations (feeding posts, sectioning posts):
- Maintain at least 1 meter distance from grounded metallic station components and at least 5 meters away from station earthing.
- Distance from station earthing can be reduced to 1 meter if cables are laid in concrete piles.
- Near OHE structures with independent earth:
- Lay cables at least 1 meter away from such earthing.
- Near traction substations:
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Outside Station Limits:
- Generally lay cables at a standard distance of 10 meters from the nearest track center.
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Signalling and Telecom Cables:
- When laying these cables in the same trench, maintain a 100-millimeter separation using bricks at 2-meter intervals.
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Power and Telecom Cables:
- Do not lay high tension (HT) or low tension (LT) power cables in the same trench as telecommunication cables.
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Cable Depth and Position:
- Bury cables parallel to the track at 1 meter depth.
- Bury cables crossing the track 1 meter below the rail flanges.
- Keep the telecom cable trench as far from the power cable trench as possible.
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Special Locations:
- Lay cables along girder bridges, over culverts, through culvert beds, over rocky terrain, and other similar locations using approved methods for each specific location.
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Cable Bending:
- Avoid sharp bends during cable laying.
- The bending radius should not be less than 40 times the cable diameter for aluminum sheathed armored cables.
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OFC and Quad Cables:
- Generally lay optical fiber cables (OFC) and quad cables in the same trench.
- Consult dedicated drawings for laying OFC/quad (chapter XIII).
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Description
This quiz covers the essential planning considerations for laying cables along railway routes. It includes topics such as cable types, conductor requirements, route planning, and distribution points, ensuring future expansion is accounted for. It provides a comprehensive understanding of the necessary steps to achieve effective cable installation in railway infrastructure.
