Track Relay and Circuit Maintenance

Track Relay Specifications

• Standard track relay types (QT, etc.) listed with associated technical specifications.

Track Feed

• Approved secondary cells needed for track circuits.
• Battery chargers/solar panels are required.
• Separate feed for each track circuit is a necessity.

DC Track Circuit Maintenance

• Power feed and track connections need continuous maintenance to ensure they remain connected to their respective track circuits.
• Relay and track connections and rail bonds need consistent joining.
• Ballast resistance must maintain a high value, and not fall below the prescribed minimum values.
• The limiting resistance of the circuit must be as high as possible.
• Insulating joints' resistance must be high.
• Rail surfaces should be clean and free of foreign matter including dust and sand.
• Proper electrical energy feeding during wet and dry conditions is important, not to over or under energize the system( minimum 0.5 ohms or no overenergizing).
• Track sleepers (concrete or wooden) type do not require different circuit management.
• Proper relay-switching configuration to prevent long term magnetism.

DC Track Relays

• Pick-up/drop-away values must stay within manufacturer-specified limits.
• Regular visual inspection (quarterly) by technicians.
• Inspection should include: armature movement checks, contact carriage wiping, contact arcing/pitting/charring, dust assessment, electrode plating condition, corrosion/breakage/cracks evaluation, presence of fungus near contacts (specific for plug-in relays) and thorough correctness assessment of labels along with present seals.
• Defective relays should be promptly replaced, and the cause documented to supervisory staff.
• Proper maintenance schedule and replacement criteria (12 years of usage, or if warranted by condition).

Insulated Rail Joints Inspection

• Insulated rail joints (IRJs) upkeep procedure must be consistent with booklet guidelines.
• Necessary components for replacement should be prepared.
• Loosening rail fastening and pulling back rails for end-post replacement when there is no gap.
• At least three sleepers on either side of the insulated rail joint must be securely packed.

Fish Bolts and Rail Integrity

• Keep fish bolts tight, tightening nuts multiple times following installation or replacement.
• Clean metal flow around rail tables to prevent short circuiting possibilities by sharp burrs.
• Brush off dust and debris from brake block surfaces to prevent short circuits.
• Pandrol clips ('J' type) must be provided at insulated joints and avoid contact with fish plates.
• Applying insulating varnish/epoxy coating to insulated joints and glued joints is needed to prevent short circuits (due to dust).
• Detect insulated joint faults (by noting voltage changes across relay terminals when the adjacent track circuit is shunted/disconnected).

Stretcher Bars and Point Connections

• Check the insulation integrity of stretcher and point rodding connections regularly(inspections periodic and ensure replacing bad insulation.)

Bond Wires/Rope Wires

• Bonds must be regularly inspected, and painted if excessive corrosion is detected.

Jumper Connections

• Regularly inspect and maintain jumper connections.
• Long jumper connections must be properly secured.

Ballast Resistance

• Minimum ballast resistance must maintain at least 2 ohms/km (station yard) and 4 ohms/km (block section).

Drainage

• Proper track drainage during rain is important, defect reports to appropriate staff are needed.

Track Joint Inspection

• Regular joint inspections (semi annually) by signal and permanent way inspectors.

Train Shunt Testing

• Periodic train shunt testing (quarterly, and upon any track adjustments or modifications, parallel areas of tracks).

Track Circuit Test Cards

• Required track circuit test cards must be documented (at least six-monthly) by signal engineers.

Batteries and Feed Apparatus

• Track feed batteries/apparatu must be properly maintained.