Transporting long timber is one of the most demanding transport tasks. Trees with trunk lengths of up to 22 metres have to be transported from the forest to storage areas or sawmills. As part of a research project, an electronic-hydraulic stability system is being developed in cooperation with an industrial partner and integrated into the trailer of a log transporter. This is a driver assistance system that supports the vehicle driver when manoeuvring by controlling the trailer steering and also stabilises the train in situations where the driving dynamics are critical.