The air quality of inner cities is an important issue – it is harmed in no small measure by the emissions of local public transit systems. In Germany there are currently 23,000 diesel-powered buses, but fewer than 200 electric buses, and of those, just over 100 trolley buses in operation. So why aren’t there more electric buses in urban transit systems, even though they’ve been available for over 100 years? They may be low-cost, energy-efficient, and locally emission-free, but due to their connection to overhead wires, they’ve always been considered inflexible. This is why we’ve designed a trolleybus with a modern technology that’s less dependent on overhead wires, to help solve the power supply issue for electric buses.

For greater flexibility we’ve developed a solution for automatically connecting and disconnecting trolleybus poles to and from their overhead wires. The contact wires can be used to recharge batteries or supercapacitors – even during uphill climbs. In addition, the electric bus can flexibly travel some stretches off-wire. The need for costly overhead wire constructions such as overhead switches simply falls away. A set of overhead wires can serve doubly for trolleys using them to travel the same route in opposite directions. Outlying districts without overhead wires can be included in service areas. The need for massive battery capacity (such as in fully battery-powered buses) can be reduced.

LibroDuct employs a stereo camera system along with a high-performance embedded pc with computer vision to detect the position of the overhead wires. Current collectors with precise positioning motors can contact the overhead wires at any desired point within the network. This can be conveniently operated from the bus driver’s seat. It’s no longer necessary to exit the bus or maneuver it precisely to a particular point to reconnect the poles to the overhead wires. There is an interface system for integrating LibroDuct into existing systems in the trolley. Existing trolleybuses can be retrofitted.