German researchers are testing a unique form of public transportation that borrows the best from busses, electric cars, trains and trams without contributing emissions. The vehicle, named AutoTram, is fully electric, but instead of running on a single charge, it charges when it stops, gaining enough power in 30 seconds to move another mile.
The project comes from the Fraunhofer Institute for Transportation and Infrastructure Systems IVI in Dresden and aims to offer the convenience, routing flexibility and affordability of a bus, minus the noise and exhaust. It also addresses the problem of lengthy battery charging cycles. While most cars are only in use for a few hours per day, public transportation vehicles can be in action around the clock, offering nearly no battery charging opportunities.
The streetcar is partly inspired by light rail systems, but doesn’t require rails or overhead lines, making it less expensive to implement. Instead, AutoTram’s tires follow white lines painted on the road and a multi-axle steering system gives it the maneuverability of a regular bus.
AutoTram stops would jolt supercapacitors in the vehicle with 700 volts during its brief stops. The team decided against using lithium-ion batteries, which are heavier and require more time to charge. A diesel generator also rides on board to serve as a back-up in case the next charging station is too far.
According to the team, AutoTram’s costs would be 30 to 50 times less than those of light rail systems, although still pricier than diesel-powered busses. The project is supported by 34.5 million euros from the German Government’s Economic Policy Program.