APS, power from the ground up
The principle:
APS is a system to power trams without overhead catenaries, allowing the tram to operate ? wire-free ? over journeys of any distance and hence to blend into the urban environment.
APS is an ALSTOM exclusivity. The Communaut? Urbaine de Bordeaux (Bordeaux Metropolitan Area) is the first city in the world to have opted for this completely new technology on 14 km of its 44 km long tram network. It has been operating since the end of 2003.
How does it work?
Power is supplied to the tram through a third rail embedded in the tracks. This third rail is made up of 8 metre-long conducting segments, which can be powered, and which are separated by 3 metre insulating joints. Power is supplied to the conducting segments by underground boxes every 22 metres. The electricity transmitted through this third rail is picked up by two friction contactors located in the mid-section of the tram. The delivery of power to the conducting segments is triggered by coded radio dialogue between the tram and the ground, and only occurs once the conducting segment has been covered by the tram, ensuring total safety for pedestrians.
The advantages:
* Preservation of the urban environment and historique heritage
* Performance levels equal to those of a conventional tram in terms of comfort and speed
* Total safety for pedestrians and road users
* Compatibility with all types of road surface
* Easy extension of the system if the line is prolonged