Tractors (haulers) are usually electrically powered vehicles and are used (often in internal operations) where transportation is regularly required over long distances and to changing destinations. For low carrying and towing loads (up to approx. 8.5 kN tractive force), tractors are generally three-wheeled with a non-driven and steered front wheel. In the case of coupled wagon trains (S. with several trailers), the wheel guidance of the trailers is decisive for the required track width. Trailers with only one steered axle have a constricting cornering behavior, which requires large track widths as the number of trailers increases. In contrast, four-wheel steering systems with coupled axles are required to maintain the track of the towing vehicle.

Source: logipedia / Fraunhofer IML