Third-Rail Insulator Failure Causes and Mitigating Practices: A Comparative Study of Multiple Case Studies in the U.S.

Abstract

Rail transit systems are one of the most important and popular types of transit systems used daily in metropolitan areas all around the world. The third rail is one of the providers of traction power in electrified rail systems, but it faces several issues, such as insulator failures. The purpose of this study is to investigate the causes of insulator failures, which have not been comprehensively studied and presented in the literature. To accomplish this objective, eight transit systems with third rails were selected to (1) investigate the characteristics of third-rail systems, (2) determine the causes of insulator failures, (3) analyze the costs associated with insulator failures, and (4) determine mitigating practices to reduce the number and cost of insulator failures. After a thorough literature review, details of eight case studies were collected from different transit agencies, and their subject matter experts were asked to complete a survey and provide input. The results revealed that a build-up of dirt was the major cause of the 17 identified causes of insulator failures; carbon dust and dirt were identified as the most present particles in third-rail systems. It was noted that transit agencies often implement multiple mitigating practices such as cleaning the insulator, performing visual inspections, and conducting regular maintenance to reduce the number and cost of insulator failures. The findings of this study will help decision-makers for transit systems make timely decisions to prevent third-rail insulator failures and adopt appropriate practices that best fit their transit system.

A review of non-destructive methods for the detection tiny defects within organic insulating materials

“…The sheath made of silicone rubber is joined to the core rod made of glass fiber-reinforced plastic through the action of a couplant to create contact-type bonding and a composite insulator (Jeenjitkaew and Guild, 2017). Interfacial defects are one of the most prevalent failure forms of composite insulators, accelerating the aging of organic materials, reducing mechanical qualities and even causing insulator strings to fail, which poses a significant threat to the regular operation of the power grid (Rouhanizadeh and Kermanshachi, 2020).…”

Development of Strategies to Prevent Third Rail Insulator Failures in Transit Systems

“…Contact rail insulators are usually made of fast-drying, nonconducting materials such as porcelain, fiberglass, or composite materials, and are installed at each supporting bracket [18,19]. Rubber insulators are increasingly used for transmission lines and have several advantages over conventionally used insulators, as they are lightweight, have a slim design that is resistant to vandalism, and cause less pollution in the environment.…”

“…Protection boards cover the top of the railway's electric third rail and are settled on the contact rail to protect personnel from coming in contact with the rail [19,21]. These boards are typically made of fiberglass, plastic, and timber [15].…”