Autonomy and energy efficiency are important criteria in urban transport. With continued focus on ensuring the proper architectural integration of trams into city centers, Alstom expanded its range of catenary-free solutions with SRS, a breakthrough ground-based power charging system for all types of tramways, including the non-Alstom built. SRS allows vehicles to run autonomously between stops without the use of catenary, offering the best adapted response to preserve the cityscape. It is also designed to address the road market by supplying power to electrical buses through ground-based charging slots at stations. It can be used by a large range of electrical buses.

SRS is based on the technology and safety principles of the proven Alstom APS solution used by Citadis trams. Whereas APS supplies power to the tram while it is still running, SRS store energy recharged during tram stations stops in less than 20 seconds. Electrical power comes from compact power supply cabinets that are smoothly and easily integrated into stations. Collector shoes (contact blocks), fitted under the tram, make contact with the conductor rail, providing electric traction power to the tram. Supercapacitors installed on the roof of the tram store energy via a ground-based conductive rail which provides traction power to the vehicle through the collector shoes.

Alstom is the only manufacturer with the broadest and most reliable range of catenary-free solutions including APS, on-board batteries, supercapacitors and SRS, to ensure the proper architectural integration of trams into city centers, according to a company press release. For improved efficiency, these different technologies can be combined, as will be the case for the Citadis tram system of Rio, Brazil, which will run 80% on APS and 20% on supercapacitor.