Transit Traction Power Cables: Replacement Guidelines

The transit industry uses insulated cable for traction power supply and negative return cables between traction power substations, tie switches, and points of delivery to the vehicles, whether third (contact) rail or overhead contact system (OCS). In addition, third rail systems use jumper cables to provide continuity of power around third rail gaps and expansion joints. The conductor insulation system used for traction power cables as well as for lower voltage power distribution and signal/communication systems typically has a specified life of 30 years. Many of the transit systems in the United States are that age or older with original cables still in service. Many cables within transit tunnels have had failures because of the water penetration through and around the cable insulation, causing damage to the insulation and corrosion of the copper conductor. In some subway tunnels, the conduits themselves have degraded to the point where they cannot be cleaned out and reused for their original purpose. Transit systems have experienced cable fires and system-wide closures due to the degradation of traction power cable insulation. In recent years, major storms affecting the United States have inundated transit tunnels with fresh and contaminated water and exacerbated cable lifecycle concerns. Research is needed to answer key questions and to determine end of life and replacement criteria for transit traction power cables. The objective of this research is to develop guidelines for determining when to replace transit system cables. The research will include a study of current practices for (1) assessing insulation aging and (2) replacement of cables before failure, including (a) approaches used in transit systems for which there are no monitoring programs and/or testing systems, (b) factors affecting life of cable, and (c) effective practices from transit agencies.


  • English


  • Status: Completed
  • Funding: $250000
  • Contract Numbers:

    Project C-24

  • Sponsor Organizations:

    Transit Cooperative Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC    20001

    Federal Transit Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Project Managers:

    Parker, Stephan

  • Performing Organizations:

    Eastern Michigan University

    Ypsilanti, MI  United States 
  • Principal Investigators:

    Korkmaz, Kasim

  • Start Date: 20190415
  • Expected Completion Date: 20220131
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01622195
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project C-24
  • Files: TRB, RIP
  • Created Date: Jan 7 2017 1:15PM