Isolator Switches Operations

20600 Operation of Isolator Switches

• Isolator switches are used to section off overhead lines (OHE) for maintenance
• Operating handles must be kept locked open or closed
• Isolator switches are not designed to break current, only circuits with no current
• Opening a switch with current can cause severe arcing and operator danger
• Isolator switches on main lines can only be opened if the relevant sub-sector is dead, as per TPC instructions
• TPC must ensure the sub-sector is dead before opening an isolator switch
• Adjacent interruptors can be closed simultaneously

20601 Isolators in Yards and Sheds

• Isolator switches in yards/sheds can be opened if the entire section is clear (visible) and no locomotives with raised pantographs
• If conditions aren't met, follow procedures of 20600-4

20602 Maintenance Blocks

• Two types of blocks for maintenance work on electric traction installations:
  • Traffic Block: Used for major repairs; granted by Section Controller, with consulted TPC
  • Power Block: Used for smaller repairs that doesn't need a traffic block, granted by TPC and by Section Controller
• Three types of power blocks
  • Emergency Power Block: Used in case of system breakdown or injuries
  • Pre-arranged Power Block: Used for planned work after passage of scheduled trains
  • Locally Arranged Power Block: Used for siding, yard, or shed work.

20603 Power Blocks

• Power block types : Emergency, Pre-arranged, Locally arranged

20604 Emergency Power Blocks

• Power block is required in cases like OHE break down, injuries, or equipment falling down.

20605 Reporting Abnormalities in OHE

• All railway officials must report issues like malfunctions, damaged equipment, or safety issues, either directly to TPC or through Station Master or Section Controller.

20606 Request for Emergency Power Block

• The person reporting a breakdown must provide details like location of issue, nature of issue, and name of reporter.

20607 Action to be taken by TPC

• Upon receiving the report, TPC will de-energize affected section, advise Section Controller to switch off, and arrange for protection measures

20608 Precautions after Emergency Power Block is imposed

• No work on the affected lines will begin until authorized OHE personnel arrive
• Power must not be restored by TPC until authorized personnel has confirmed earthing at multiple points.

20609 Identification of the Sectors, Sub-Sectors, and Elementary Sections

• It's crucial that personnel identify areas correctly.
• Sectors are areas of overhead lines that can be powered by a feeder circuit breaker at a substation.
• Sub-sectors are identified by the names of the switching stations.
• Elementary sections are numbered according to direction of power supply, using two/three digits to describe the interrupter, and two-digits for the elementary section number.

20610 Telephone Messages

• All messages regarding shutdowns, restorations, permits-to-work etc must be confirmed by private number exchanges for clarity
• A private number book must be maintained for all telephone exchanges to ensure clear communication and accountability.

20611 Procedure for Obtaining Traffic or Power Blocks and Permits-to-work

• Urgent work needs immediate power blocks and permits-to-work.
• Maintenance statements for maintenance work must to be submitted by 10am on the first working day to the area Sr. DEE (TrD), containing the particulars of works, location, and trains involved, whether the track is for steam or diesel.
• A consolidated statement for weekly work must be submitted by 12 noon on Wednesday to the Senior Divisional Operating Manager

20612 Pre-arranged Power Block

• For pre-arranged power blocks, Section Controller confirmation for availability must be obtained two hours before the required time.
• Maintenance teams should be ready in time.
• Section Controller ensures protections are in place on neighboring sectors.
• TPC confirms availability and instructs staff to begin work.

20613 Restoration Of Supply After a Permit-to-work is Returned

• After work is complete, ensure all employees and materials are removed from the area
• All security measures should be ensured prior to reconnection
• TPC will inform the relevant personnel to restore power supply

20614 Work by other than Authorized Persons

• unauthorized personnel cannot work on electrical equipment without a written permit-to-work from an authorized person(Senior Linesman or above)
• An authorized person will earth the equipment and provide a permit- to-work card before handing over the work permit to the worker in-charge
• Once work is completed, permit-to-work is cancelled

20615 Local Cancellation of Permit-to-Work When Telephones are Interrupted

• If phone line is down, follow instructions listed in para 20615
• Local personnel must restore normal (Live) conditions (if possible) and ensure no other groups have a permit-to-work during the period.

20616 Multiple Working Parties

• For multiple parties working on the same sub-section, only one person can receive the permit-to-work in charge of the work.
• Other parties can only work in the designated area with permission from the authorized party.

20617 Entry in the Log Book

• Entries of permit-to-work issuances, equipment status, and timing for all equipment must be recorded.
• Log Book should record all specifics from the phone call (private number) between the personnel and the TPC.
• Maintenance works and changes are recorded in the log book immediately as per regulations.

20618 Work Inside Loco Shed or Car Shed

• Contact the Traction Foreman, Assistant Foreman, or Chargerman (RS) for work permits in such cases
• No need to report to TPC

20619 Local Blocks

• Local electrical blocks (not affecting main lines) require manual isolator control.
• The Station master and involved parties are responsible.
• TPC must be notified beforehand and afterwards.

20620 Protective Measures for Power Blocks

• Personnel working with energized equipment need a thorough understanding of safety precautions during power blocks.
• Protective measures are described in detail for working on sections with live electrical equipment.

20621 Longitudinal Protection

• Overhead lines are sectioned and insulated to prevent short circuits during power blocks.
• Sufficient distance between sections ensures safety of work-force.

20622 Transverse or Cross Protection

• Section insulators on crossovers prevent electrical connection between different sections.
• Section insulators prevent live OHE lines from connecting to dead section.

20623 Procedure for Arranging Longitudinal and Transverse Protection

• The Section Controller coordinates safety with Station Masters
• Working rules ensure protections are adequate before power block approval

20624 Station Working Rules for Longitudinal and Transverse Protection

• Clear station working rules should accompany safety procedures for power blocks.
• All personnel must ensure familiarity with procedures to ensure safe operation for power blocks.

20625 Protection of Dead Section

• Signaling systems and manual equipment lockouts are key in protecting dead sections
• The signaling devices are used to prevent any accidental contact with live equipment.
• Procedures and precautions are detailed with emphasis on safety procedures and equipment control.

20626 Shunting Movement Towards Dead Section

• Shunting movements for non-electric trains are permitted in dead zones under specific conditions (no electric train in the zone, etc)
• Personal inspection from Station Master to validate these conditions must be completed first.

20627 Movement of Other than Electric Trains

• Safe passage for non-electric rolling stock in sections with energized equipment, requires specific conditions
• Checking for presence of live OHE equipment, and verifying their proper isolation, is mandatory.
• Safety precautions are stressed to avoid accidents.

20628 Standard Forms for Power Block Messages

• Form ETR 1, ETR 2, ETR 3, ETR 4 are specific forms for power block messaging.
• Formal documentation is necessary for all power block communications to ensure clear communication
• Information on all forms must be correct and clear.