One size fits all

researchers have developed the Autotram, a modular street vehicle that can be operated as a normal bus or have an additional articulated section fitted for more capacity.

Fraunhofer worked with Hübner to devise the vehicle, which can operate in uni-directional or bi-directional mode without the need for rails or overhead lines. The articulated train trundles through the streets on tyres like a bus.

The Fraunhofer Institute for Transportation and Infrastructure Systems IVI in Dresden presented a prototype of this transportation system to industry specialists a year ago. In collaboration with Hübner, the scientists have now taken the concept further.

An active multiple-axle steering system with integrated guidance ensures a safe journey. Based on video and differential GPS, the system assists the driver of the AutoTram and enables him or her to steer the vehicle accurately, even round sharp bends.

The 24m bi-directional vehicle consists of two low-floor modules, joined back-to-back by a symmetrical articulated coupling made by Hübner. On routes with a low passenger volume, the two modules are separated and used as single buses. If a particularly large number of passengers are expected, an additional module can be inserted, extending the AutoTram into a high-capacity vehicle 36m long.

Autotram uses a hybrid drive, drawing its power from a 180kW diesel engine and a flywheel energy storage system (4kWh/200kW). The storage system absorbs part of the braking energy, enabling the AutoTram to travel up to 2km without noise or emissions.

According to Fraunhofer, Autotram is sparking interest among public transport operators. The system is between 30 and 50 per cent cheaper than conventional railway systems.