Investigation and Mitigation of Insulated Joint Electrical Failure

Transit agencies use electrical traction (overhead catenary or third rail) for the propulsion of trains, which is typically designed using high AC or DC voltages. The running rails are used as part of the system to return negative power to substations. Insulated rail joints are track work components installed in the rails to provide a train control circuit and traction power segment separation between blocks. Insulated joints are implemented in the design of both freight and transit railroads, which operate in vastly different system environments. Freight railroads are typically designed to use low-voltage/low-amperage train control systems with diesel power while transit is typically designed to use train control systems that function in high voltage/high amperage (traction power negative return) systems. Some transit agencies have experienced significant failures of insulated joints related to arcing of the traction power negative return currents. With higher currents resulting from AC propulsion, insulated joint failures have become more problematic and more frequent across many transit systems. In some locations, the same insulated joints have failed multiple times in a short span of time. These failures result in unplanned delays to passengers; additional expenses related to repairs and damage to the track, train control systems, and traction power systems; and can contribute to stray currents that damage other infrastructure. Research is needed on insulated joint failures in high voltage/high current transit environments. Insulated joint failure of in-service designs needs to be investigated in order to develop new guidelines to locate and diagnose problematic insulated joints and recommendations leading to modified insulated joint practices, with possible recommendations for control of the heavy negative returns from AC propulsion rail cars. The objectives of this project are (1) to identify potential causes of insulated joint electrical failures, particularly those under high currents resulting from AC propulsion; (2) to identify and document the electrical conditions under which various types of joint failures occur; (3) to develop guidelines for maintenance personnel to diagnose insulated joint electrical failures and determine the best mitigation of the root causes; and (4) to recommend additional research needed to address root causes of insulated joint electrical failures.


  • English


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

    Project D-20

  • 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:

    Garcia-Colberg, Mariela

  • Performing Organizations:

    MxV Rail

    350 Keeler Parkway
    Pueblo, CO  United States  81001
  • Principal Investigators:

    Brown, Michael

  • Start Date: 20240528
  • Expected Completion Date: 0
  • Actual Completion Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 01758786
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project D-20
  • Files: TRB, RIP
  • Created Date: Nov 23 2020 3:58PM