Safety Regulations for OHE Operations

All accessible metallic parts must be grounded (earthed) after being de-energized.

Each team working on overhead equipment (OHE) needs at least two separate grounding points, one on either side of their work area.

If the distance between working areas is greater than 100 meters, additional grounding points must be placed to keep the distance between earths under 100 meters.

Specialized earthing poles are needed for temporary grounding of overhead equipment. These poles must have flexible cabling with sufficient cross-sectional area.

The earthing clamp should be placed on a mast, or a traction rail and at least one span away. Secure connections are essential.

The earthing clamps must be firmly attached to the mast or rail before being connected to the OHE conductor.

Obtaining a permit to work, ensuring power is off, and posting warning personnel for approaching trains are essential before work begins.

Connect the earthing cable to earth before connecting it to OHE.

Fix the earthing clamp first to the rail/structure, and then to the OHE.

Set up two temporary earths on the opposite sides near the work area on OHE.

Once temporary earth on both sides are in place, maintenance work can proceed.

Remove earthing cable hook from OHE, then the clamp from rail/structure, in the reverse order of installation.

Inspect the earthing cable every fortnight for strand breakage, and renew if more than 20% strands are broken. Inspect cable for fraying and breakages during any use.

Position the discharge/earthing pole during accidents involving OHE slewing, avoiding crane or track work interference.

When working on OHE or conductors without electrical bonding, earth both ends of conductors at two different spots after switching off supply to each part of the OHE.

Treat neutral sections as live equipment and earth separately at two points on either side of the work site.

This form is used by the Traction Power Controller to request a power block for electric traction purposes. It details the required duration, lines affected, and the location of the block.

This form is used by the Section Controller to inform the Traction Power Controller that the power block has been established. The form includes the serial number, date, and time of the block.

A message sent by the Traction Power Controller to the Section Controller requesting to block power to certain lines for electrical work. The message includes details like time, duration, and lines affected.

When a power block message is sent, the receiving party must acknowledge receipt. This is done by signing the carbon copy of the message form.

All communication about power block requests and acknowledgements should be followed up with the exchange of private numbers between the parties involved.

A minimum of 2 meters of electrical clearance must be maintained from live OHE to adjacent tracks or structures.

Isolators at the neutral section of OHE should be open during petroleum product loading/unloading to de-energize and earth the OHE.

The supervisor in charge of OHE maintenance in the field must submit a daily report to the ATFO.

Linesmen must record foot-patrol inspections in a register maintained by each Section Supervisor.

A dedicated register is used to record maintenance activities on cantilever assemblies.

Regular measurements of contact wire thickness are recorded in a dedicated register.

Records of clearance under over-line structures are maintained to ensure safe passage of trains.

Regular Earth resistance measurements are recorded to ensure proper grounding of OHE.

A register is used to track and record the results of current collection tests.

Each depot/sub-depot maintains a register for its regulating equipment, recording adjustments, catenary and contact wire cuts, etc.

When disconnecting a booster transformer (BT) from 25kV lines, power must be switched off to both sections it connects, the isolator opened to disconnect the BT from the OHE and to make the OHE through, the secondary winding disconnected from the return conductor, the return conductor earthed, and mid-point rail links opened.

After disconnecting the BT's secondary winding from the return conductor, the return conductor must be earthed at the point of disconnection.

When disconnecting a BT, the mid-point rail links on both sides of the BT should be opened to allow booster cells on either side to extend over a longer section.

After disconnecting a BT, the OHE and return conductors need to be made through before 25kV power supply can be restored.

A disconnected BT can increase interference in nearby communication circuits.

Isolating Switches on the 25kV system should only be opened or closed when no current is passing through them.

Specific measures are needed when working near petroleum sidings to prevent stray current risks and ensure safety.

An equipotential link, connected via a switch, is required between petroleum sidings installation earth and the track to equalize their electrical potential.

Neutral zones (insulating joints) are set up in the track and contact wire to prevent stray current propagation.

Petroleum sidings require longitudinal and transverse bonds on tracks and metallic structures to ensure proper electrical conductivity and safety.

All metallic parts within reach (either directly or through tools etc) shall be earthed, after they are made dead.

Each working party shall be protected by at least two independent earths, one on each side of a working party.

If the distance between the working parties exceeds 100 m intermediate earths shall be provided in such manner as to ensure that the distance between earths does not exceed 100m.

For providing temporary earth on the OHE or other equipment after it has been made dead, only discharge / earthing pole assembly specially designed for this purpose alone should be used.

The following sequence of operations shall be carried out while providing temporary earths on OHE: 1.Men shall be posted on both sides of the site of work to warn the working party of any approaching train on the same track and adjacent track(s). 2.The permit-to-work shall be obtained prior to commencing work to make sure that power supply has been switched off. 3.For providing temporary earth on the OHE or other equipment after it has been made dead, only discharge / earthing pole assembly specially designed for this purpose alone should be used.The cable shall be flexible and should have adequate cross-section (40 mm2) to be able to withstand short circuit currents. 4.Fix the earthing clamp securely to a mast at least one span away on one side of the work site after making sure that the mast to earth rail bond of this masts is intact.Alternatively, the clamp may be fixed to the bottom flange of one of the traction rails, taking the cable under the rails.In single-rail-track-circuited sections, the earthing clamp should be fixed to the traction rail i.e., non-track-circuit rail; on double-rail-track-circuited sections the earthing clamp should be fixed to the mast.The mast-end or rail-end clamp of the discharge / earthing pole assembly should be checked for tightness just before connecting the top clamp on to the OHE as the earthing clamp fixed to the rail or mast in advance could have worked loose. 5.Hook securely with a snap action the top clamp of discharge / earthing pole assembly to the OHE conductor close to the mast / structure and tie the earthing pole to the mast / structure.

Hook securely with a snap action the top clamp of discharge / earthing pole assembly to the OHE conductor close to the mast / structure and tie the earthing pole to the mast / structure.

When connecting an earthing cable, first connect the clamp to the traction rail/mast/structure, then connect the top clamp to the OHE. Reverse this order for disconnecting.

Inspect the earthing cable every two weeks for broken strands and fraying. Replace it if more than 20% of the strands are broken.

When working on OHE or conductors that are not electrically bonded, each end of the conductor must be earthed at two separate points after switching off the supply to both parts of the OHE.

Treat neutral sections as live equipment and earth them separately at two points on either side of the work site before starting work.

Connect the earthing cable to earth (rail, structure) BEFORE connecting it to the OHE.

After maintenance work is completed, the OHE needs to be made through (connected) before power can be restored.

When disconnecting a Booster Transformer (BT) from 25kV lines, follow these steps:

1. Switch off power to both sections connected to the BT.
2. Open the isolator to disconnect the BT from the Overhead Equipment (OHE) and make the OHE through.
3. Disconnect the secondary winding of the BT from the return conductor and make the return conductor through by jumpering.
4. Earth the return conductor at the disconnection point.
5. Open the mid-point rail links on both sides of the BT to extend booster cells temporarily.

After disconnecting the BT's secondary winding from the return conductor, the return conductor must be earthed at the point of disconnection to ensure safety and prevent stray currents.

Mid-point rail links connect sections of track. When disconnecting a BT, these links are opened to allow booster cells on either side of the BT to extend over a longer section, maintaining power supply.

After disconnecting a BT, the OHE and return conductors need to be made through before restoring the 25kV power supply. This ensures that both sections are electrically connected and safe.

A disconnected BT can increase interference in nearby communication circuits due to changes in electrical fields. This necessitates replacing the faulty BT as soon as possible.

Isolating switches on the 25kV system should only be opened or closed when no current is passing through them to prevent electrical accidents.

An equipotential link connects the petroleum sidings installation earth to the track, ensuring that both are at the same electrical potential to prevent stray currents.

Neutral zones (insulating joints) are placed in the track and contact wire near petroleum sidings to prevent the propagation of stray currents, ensuring electrical safety.

Petroleum sidings require longitudinal and transverse bonding on tracks and metallic structures to ensure proper electrical conductivity and safety, reducing resistance and preventing hazards.

A record maintained by depots and sub-depots that details patrolling and maintenance activities carried out on 25kV feeder lines.

A record that documents the annual check of implantation at crucial locations.

A register that keeps track of the height of contact wire and height gauges at level crossings.

Each depot or sub-depot keeps a detailed account of every OHE breakdown within its jurisdiction.

Standard forms used for communication between the Traction Power Controller (TPC) and other relevant personnel to establish or remove power blocks.