Numerous technologies exist for providing electrical power to transit systems. Where overhead space is costly or where overhead structures may be deemed obtrusive, 3rd rail is a reliable and cost-effective way to provide considerable power to transit vehicles. Since the early years of railway electrification, 3rd rail conductors have evolved from steel to aluminum/steel composite to aluminum/stainless steel compositions. Aluminum stainless steel conductors are currently used in approximately 40% of the over 10,000km of 3rd rail systems worldwide. Adoption of this technology in the United States, however, stands at less than 5%.
This paper examines aluminum/stainless steel 3rd rail technology from technical and economic perspectives. The author makes a case for its adoption in new and existing 3rd rail systems in the United States.