Traction Systems Bonding and Earthing

An electrical connection between non-current-carrying metallic parts of traction masts, structures, or supports and rails.

A bond (electrical connection) between two rails on one or adjacent tracks.

A conductor on traction masts/structures/supports, connected to the metallic parts and earth.

Connection to the earth's conductive mass via an electrode.

A metal piece (plate/pipe) connected to the earth's mass.

A bond providing low impedance for traction current, high impedance for track circuits.

Electrical connection across a rail joint.

Continuous rail section, with or without welded joints, but no fish plates.

A bond connecting non-current-carrying metallic parts of a traction mast or structure to the traction rail.

An electrical connection across a rail joint, provided by Signalling & Telecommunication, to facilitate track circuit current flow.

A connection for electrical continuity, kept as short as possible with minimal bends.

A non-track-circuited rail in a wired track, not needed for signalling, and potentially earthed.

A bond made of copper conductors with metal ferrules pressed on and bent as needed.

A track system with a 25 kV AC 50 Hz single-phase overhead equipment.

Not essential like in DC traction; provides return current path near substations to reduce rail-earth voltage and spread current in earth.

Connecting rails to ensure low voltage for safety and reduce voltage drop for track circuits.

Bonding of traction rails to lower ac voltage drop for track relays and provide low resistance for traction/signalling currents.

Track circuits with one rail bonded to ensure low voltage and low resistance paths for both traction and signalling currents.

Track circuits with both rails bonded to make a low resistance path and distribute traction return current evenly in both rails.

Bonds placed at insulated joints to create a continuous path for traction return current.

Bonds on track-circuited rails, for low resistance connection for signal currents.

Connecting non-current carrying metal parts of structures to the traction rail or earth wire for safety.

Bonding only one leg of a portal structure to the nearest traction rail.

Bonding each mast of a head span to the nearest traction rail.

A bond at structure bond location connecting to an adjacent rail when the structure is near a platform.

Electrical connection of tracks to provide a complete electrical path for traction current, preventing unwanted electric signals in track circuits.

50 meters beyond the last traction mast in unwired tracks, to complete the electrical circuit.

Mild steel with a cross-sectional area of at least 200 mm² used for bonds.

Connects traction rail and mast/structure metals directly using galvanised steel fasteners.

Connects traction rails and track-circuited rails using galvanised steel fasteners, avoiding insulated rail joints.

Electric/gas welding used when traditional rail bonds are not feasible.

Connects two traction rails or non-track-circuited rails of different tracks.

Buried rail connection for return current using GI nuts, bolts, and spring washers.

Copper equivalent of at least 50 mm² for bonding traction masts/structures/supports in tunnels.

Sections where only one rail is used for track circuits, requiring complete rail bonding.

If a track circuited rail is 350 meters or less, a cross bond must be installed between the rails immediately outside the track-circuited section's ends.

In single-line sections, even if future doubling is planned, the non-track circuited rail needs rail bonds along its entire length plus 50 meters on both ends. These rails must also have earth connections spaced no more than 100 meters apart, using two separate steel strips/flats each with a minimum cross-section of 200 mm².

In double-rail track-circuited sections, both rails require rail bonds. At insulated joints, an impedance bond is needed. Since no traction rail is available, an earth wire is required on the structure or support. If the wire is longer than 1000 meters, it must be electrically broken with insulators at intervals not exceeding 1000 meters, each section grounded at traction masts no farther apart than 500 meters.

Starting across from a traction sub-station/feeding post, all traction rails need bonds for a 1000-meter radius on either side. Additional cross-bonds are also needed at 300, 500, 700 and 1000 meters from the traction station

A wired track on wooden or concrete sleepers is considered if there are not more than six metallic sleepers in any 350-meter length of track.

An electrical connection between non-current-carrying metallic parts of traction masts, structures, supports, and rails.

A bond between two rails (either on the same or adjacent tracks).

A wire running along traction masts, connected to their metal parts and to earth.

Connection to the general mass of the earth, usually via an electrode.

A metal plate or pipe connected to the earth's mass.

A bond providing a low impedance path for traction current and a high impedance path for track circuits.

An electrical connection across a rail joint.

A continuous rail section, potentially with welds, but no fish plates.

Electrical connections ensuring a complete path for traction current in a track section.

50 meters beyond the last traction mast in unwired track sections.

Mild steel with a minimum cross-sectional area of 200 mm².

Connects traction rail to mast/structure metals using galvanized steel fasteners.

Connects traction rails across fish plate joints, avoiding insulated joints.

Electric/gas welding used when traditional rail bonds aren't suitable.

Connects two traction rails of the same or adjacent tracks.

Connections of return current to traction rails through buried rails using GI parts.

Copper equivalent of at least 50 mm² for bonding traction masts/structures/supports in tunnels.

Sections using only one rail for track circuits, requiring full rail bonding.

Connecting traction rails to lower AC voltage drops for safety, improve track circuit performance, and provide a low resistance path for traction and signaling currents.

Track circuits utilizing one rail for signaling, necessitating bonding to maintain low voltage and low resistance paths.

Track circuits with two rails used for signaling, requiring bonding of both rails to achieve a low resistance path and even current distribution.

Bonds placed at insulated joints to create a continuous low resistance path for traction return current while maintaining high resistance for track circuits.

Bonds provided on track-circuited rails, ensuring a low resistance connection to facilitate signaling current flow.

Connecting non-current-carrying metallic parts of traction masts, structures, or supports to the nearest traction rail or earth wire for safety.

Bonding only one leg of portal structures to the nearest traction rail for safety.

Bonding each mast of a head span to the closest traction rail for safety.

Bonding at the location of a structure bond to connect to the adjacent traction rail when the structure is near a platform.

Bonding traction rails within a 1000-meter radius of traction substations/feeding posts, with additional cross-bonds at regular intervals (300, 500, 700, and 1000 meters).

If a track-circuited rail is 350 meters or less, a cross bond must be installed between the rails immediately outside the track-circuited section's ends.

In single-line sections, even if future doubling is planned, the non-track-circuited rail needs rail bonds along its entire length plus 50 meters on both ends. These rails must also have earth connections spaced no more than 100 meters apart, using two separate steel strips/flats each with a minimum cross-section of 200 mm².

In double-rail track-circuited sections, both rails require rail bonds. At insulated joints, an impedance bond is needed. Since no traction rail is available, an earth wire is required on the structure or support. If the wire is longer than 1000 meters, it must be electrically broken with insulators at intervals not exceeding 1000 meters, each section grounded at traction masts no farther apart than 500 meters.

Starting across from a traction sub-station/feeding post, all traction rails need bonds for a 1000-meter radius on either side. Additional cross-bonds are also needed at 300, 500, 700 and 1000 meters from the traction station

A wired track on wooden or concrete sleepers is considered if there are not more than six metallic sleepers in any 350-meter length of track.

An area in railway tracks and overhead equipment designed to isolate the main railway network during loading/unloading operations to prevent stray current propagation.

Electrical connections along the length of a siding or secondary loop line rails.

Electrical connections across rails of a siding or secondary loop line, spaced no further than 30 meters.

Connections to ground at both ends of the siding or secondary loop line, immediately outside the neutral zone.

A connection that maintains electrical continuity between petroleum installations and the siding rails during loading/unloading.

Electrical connections between non-current-carrying metallic parts of traction masts, structures, and supports, and the rails.

Steel structures within girder bridges are connected to the traction rail or earth using steel strips/flats.

Bonds connecting traction rails on a bridge, at intervals not exceeding 100 meters.

In a single-rail track section, the non-track-circuited traction rail needs rail bonds and grounding at both ends of the bridge.