Synthesis of Information Related to Transit Practices. Topic SD-05. Third Rail Insulator Failures- Current State of the Practice

Metro rail systems use an electrified third rail to obtain traction power for the rail cars. The third rail is installed on insulators that get covered with steel dust, rust particles, brake dust, carbon dust and other conducting particulates generated by operating trains. The particulates accumulate over time causing the insulators to fail resulting in leakage current, electric arcing, smoke and fire. Insulator failures can cause delays in one portion of the transit system and have cascading effects to an entire metro rail network. Thousands of passengers can be delayed and stranded, increasing costs for passengers, businesses, and metro rail systems alike. Further, failure incidents can cause passenger concerns and discourage people from using metro rail systems. The problem is exacerbated by incidents occurring in tunnels. This synthesis will document the current practice and lessons learned from the use of the insulator systems and how transit systems prevent insulator failure. The document will include: (1) Third rail infrastructure specification and characteristics by agency ( e.g. insulator materials, mounting configurations, type of contact rail, environmental factors, legacy vs. modern, newer systems, etc.); (2) Types and causes of failures ( e.g. electrical. mechanical, operational); (3) Rate of failures; (4) Impacts of failure to agencies’ operations (e.g. manpower, costs, retention of customers, etc.); and (5) Maintenance and failure mitigation methods. Information will be gathered by a literature review that synthesizes previous studies, Federal Transit Administration (FTA) Innovations Deserving Exploratory Analysis (IDEA) and SBIR reports and international sources (e.g. agency reports, peer reviewed journal articles) and questionnaires, with follow-up interviews as needed, of transit agencies that operate third rail. The report should include case examples from most of the transit agencies operating third rail (minimum of eight) that will gather information on the state-of-the-practice, emphasizing lessons learned, opportunities and challenges. The needs for future research and gaps of information should also be discussed. This synthesis will be useful to industry professionals and transit agencies.


  • English


  • Status: Active
  • Contract Numbers:

    Project J-07, Topic SD-05

  • 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

  • Principal Investigators:

    Vohra, Arun

  • Start Date: 20170929
  • Expected Completion Date: 0
  • Actual Completion Date: 0
  • Source Data: RiP Project 41623

Subject/Index Terms

Filing Info

  • Accession Number: 01634930
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project J-07, Topic SD-05
  • Files: TRB, RiP
  • Created Date: May 18 2017 1:01AM