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:
• 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.)
• Types and causes of failures ( e.g. electrical. mechanical, operational)
• Rate of failures
• Impacts of failure to agencies’ operations (e.g. manpower, costs, retention of customers, etc.)
• Maintenance and failure mitigation methods
Information will be gathered by a literature review that synthesizes previous studies, FTA 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.
Transportation Research Board - Transit IDEA Project 36 - Cleaning Device for Electrified Third Rail Insulators
FTA SAFETY ADVISORY 16-2
Teleconference with Consultant:
Edward J. Abel, Jr., Southeastern Pennsylvania Transportation Authority
Muhammad N. Akhtar, WMATA
Michael Ford, RTD Denver
Joseph Gushue, Massachussetts Bay Transportation Authorithy
Ethan Kim, LTK Engineering Services
Daniel Tinsley, Chicago Transit Authority
Richard Watson, BART
Roy Wei Shun Chen, Federal Transit Administration-TRI
Stephen J. Andrle, Transportation Research Board