Alstom Citadis

The most popular solution is Alstom's proprietary ground-level power supply (APS, first used in Bordeaux and subsequently in Angers, Reims, Orleans, Tours, Dubai, Rio, and Sydney), consisting of a type of third rail which is only powered while it is completely covered by a tram so that there is no risk of a person or animal coming into contact with a live rail.

On the networks in France and in Sydney, the trams switch to conventional overhead wires in outer areas,[9] but the Dubai vehicles are the first to employ APS for its entire passenger length (although they are still equipped with pantographs for use in the maintenance depot).

Another option is to use on-board batteries to store electrical power, allowing brief periods of catenary-free operation without the need to install special infrastructure.

The Citadis trams in Nice operate off a set of nickel metallic hydride batteries in two large open spaces where overhead wires would be an eyesore.

[10] This has since been superseded by a supercapacitor-based energy storage system (SRS)[11] which is in use in Rio de Janeiro (alongside APS), Kaohsiung, and along a new line in Nice.