Practices and Recommendations Concerning Determination of End-of-Life of Transit Traction Power Cables and Determination of Replacement Criteria

The transit industry utilizes jacketed insulated cable for traction power supply and negative return cables between traction power substations, tie switches, and point of delivery to the vehicles, whether third (contact) rail or overhead contact system (OCS). In addition, third rail systems have jumper cables to provide continuity of power around expansion joints in the third rail. The outer jacket as used for traction power cable as well as for lower voltage power distribution and signal/communication systems typically has a specified life of thirty (30) years. Many of the transit systems in the United States are that age or greater. In addition, major storms along the east coast of the U.S. have inundated transit tunnels with not just tons of fresh water, but sea water as well. A lot of the cables within the transit tunnels have had failures due to the water penetrating through the outer jacket and causing damage to the hygroscopic insulation and also causing corrosion of the copper conductor within the insulation. Many of the transit tunnels that connect Manhattan with the other boroughs of New York City were flooded during Hurricane Sandy, as well as other major storms. Transit agencies in the New York City region, including northern New Jersey, sustained major water damage during Hurricane Sandy. Inspections of traction power, signaling, and remote-operated track switch machines revealed cables with repeated damage from Hurricane Sandy as well as storms in years past. In subway tunnels from Manhattan to New Jersey, the conduits themselves have degraded to the point where they cannot be cleaned out and reused for their original purpose. In Washington, DC, cable fires have occurred due to the degradation of traction power cable sheathing and insulation. The objective of this research is to develop a set of guidelines for determining when to replace transit system cables. The research will include a study of current practice for measuring insulation aging and replacement and pro-active replacement of cables before failure. In addition, the research will include current practice concerning cable replacement in transit systems for which there is no monitoring system. Research into cable monitoring systems, such as monitors that measure cable shield to earth ground resistance trends should also be included.


  • English


  • Status: Proposed
  • 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

  • Start Date: 0
  • Expected Completion Date: 0
  • 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 1:00AM