Abstract: A tractor unit (10) and a trailer unit (14) are connected by a connecting pin (33) on one unit (12, 14) which is in use received in an opening (21) in a connecting surface of the other unit, the connecting pin (33) including a sensor device (70) to sense loads imposed on the connecting pin (33) as the trailer unit (14) tends to decelerate or accelerate relative to the tractor unit (12), there being a control system, including a controller (65) which receives signals from the sensor device (70) representative of loads imposed on the connecting pin (33), and at least one electrical motive machine (50) is controlled, the machine (50) being capable of being electrically driven by power from an electrical storage device to provide drive to drive at least one ground engaging wheel (45a, 45b) and of generating electrical power for storage by an electrical storage device (58), such as to minimize the loads imposed on the connecting pin (33).

Abstract: A tractor unit (10) and a trailer unit (14) are connected by a connecting pin (33) on one unit (12, 14) which is in use received in an opening (21) in a connecting surface of the other unit, the connecting pin (33) including a sensor device (70) to sense loads imposed on the connecting pin (33) as the trailer unit (14) tends to decelerate or accelerate relative to the tractor unit (12), there being a control system, including a controller (65) which receives signals from the sensor device (70) representative of loads imposed on the connecting pin (33), and at least one electrical motive machine (50) is controlled, the machine (50) being capable of being electrically driven by power from an electrical storage device to provide drive to drive at least one ground engaging wheel (45a, 45b) and of generating electrical power for storage by an electrical storage device (58), such as to minimise the loads imposed on the connecting pin (33).