Failures of third rail insulators, which often impose problems that affect the serviceability of transit systems, rarely have been investigated. This study examines various aspects of third rail systems, identifies causes of insulator failures, and develops and categorizes preventive strategies. To accomplish the goals, the existing literature was reviewed and analyzed to identify various characteristics of third rails and insulators. Then, five transit case studies were analyzed to determine the characteristics of third rails, identify the causes of insulator failures, and evaluate the preventive strategies adopted by transit agencies. The results revealed that local environmental conditions cause degradation of insulators, with dirt build-up being the biggest contributor to failure. Performing maintenance and inspections of insulators at predetermined intervals was also shown to be very effective for preventing failure. The preventive strategies were classified into three categories: regular inspections; preventive maintenance programs; and regulation and safety, with regular inspections being the most frequently adopted. Findings of this study will serve as an appropriate source of information for practitioners who work with third rail systems and will help them adopt effective strategies.

第三轨绝缘子的故障通常会带来影响运输系统可维护性的问题，很少对此进行研究。这项研究检查了第三条铁路系统的各个方面，确定了绝缘子故障的原因，并对预防策略进行了分类。为了实现这些目标，对现有文献进行了回顾和分析，以确定第三条导轨和绝缘子的各种特性。然后，对五个运输案例进行了分析，以确定第三条导轨的特性，确定绝缘子故障的原因，并评估运输机构采取的预防策略。结果表明，当地环境条件导致绝缘子性能下降，灰尘堆积是导致故障的最大原因。还显示了以预定间隔进行绝缘子的维护和检查对于防止故障非常有效。预防策略分为三类：定期检查；预防措施。预防性维护计划；以及法规和安全性，最常用的是定期检查。这项研究的结果将为使用第三轨系统的从业人员提供适当的信息来源，并将帮助他们采取有效的策略。