MSNBC reported today that Bombardier had introduced its newest technological feat: a catenary-free, contact-less tram. The system provides a clue for the next generation of rail vehicles, and suggests a future in which trams operating in city streets all over the world will no longer have to rely on overhead catenary wires and the poles that hold them up, which can be a blot on a city’s landscape.
Bombardier’s system, called PRIMOVE, relies on electromagnetic fields released from buried circuits placed between and beneath the tracks. When passing overhead, streetcars convert the field to electricity used to power the train; in other words, the trains receive their power without contact through inductive power. This is major achievement. The charge is only activated when the circuit is completed covered by the vehicle, which ensures that pedestrians can never come into contact with electricity.
The PRIMOVE system has the added benefit of working in conjunction with another Bombardier technology, MITRAC. This system acts much like a hybrid motor in a car and recuperates power when the train brakes.
PRIMOVE will compete with technologies from rival Alstom, whose Citadis product line has been one of the industry’s top sellers in recent years. In Bordeaux in southwestern France, Alstom equipped part of the city’s light rail line with a ground-level power supply system (called APS) through 12 km of the historic core. Along the rest of the line, the trains use less expensive catenaries for power. This system allows the train to collect power from a third rail placed between the two tracks; power is only supplied when the train is travelling directly above. Unlike Bombardier’s design, though, APS is exposed to the elements – it is a visible third rail. In Bordeaux, there have been some problems with water logging, and as a result, it would be difficult to implement such a system in an area with heavy precipitation rates.
As a result, Bombardier’s technology has a major advantage over Alstom’s, in that it can work in all weather conditions. The fact that the power supply is buried underground ensures a higher degree of reliability and little need for future maintenance. This is a promising technology for future trams and will eliminate a common argument made against LRT or streetcar systems: that their associated catenaries desecrate the landscape.
Alstom has also developed a battery-powered tram for the southern French city of Nice. The trains travel through the central’s city square, and in order to avoid disrupting the architectural unity of the space, the system’s designers wanted to get rid of the overhead catenaries in this area. Alstom, then, equiped the trains with batteries that power them for 100 or so meters across the square. This is an interesting alternative for small distances, especially since it is probably cheaper to install, though Bombardier has yet to have its system ordered and put into active use, so we’ll see.
Image above: a depiction of PRIMOVE in use, from Bombardier