Active Bogie Steering System from Liebherr for High-Performance Locomotive

All rail vehicles are ‘guided systems’, i.e. they must never leave their tracks during operation. When entering a curve (bend), the locomotive chassis is guided into the curve by the forced guidance, the rail. This results in transverse forces in excess of 60 kN acting on the rail. In addition, there is a loss of friction loss between the wheel and the rail, which is a strain on the material. A Liebherr hydraulic bogie steering system enables these undesirable effects to be significantly reduced.

Four electro-hydraulic actuators (EHA) support the deflection of the chassis during curve travel with a turning force of 30 kN per bogie.

Implementation is simple and retrofitting is also easy. For this purpose, the conventional rotary dampers are replaced by Liebherr electro-hydraulic actuators (EHA) and connected to a separate controller in the vehicle body. The hydraulic system operates almost independently of the vehicle control system. Only the electrical supply for the controller, the enabling of the electrical supply for the motor pump unit and the direction signal must be made available to the system. A displacement sensor in the actuator detects the bend. From a bend radius defined by the software (e.g. 400 m), the hydraulic system is activated by supporting the chassis when turning to the left or right with a constant force of 30 kN per bogie. Depending on the direction of travel, the EHA then pushes or pulls with a constant force. This reduces the transverse forces on the rail, but also the friction losses in the bend, and the infrastructure is spared. Traction efficiency is improved; the locomotive has more tractive power and consumes less energy. The system is passive for larger bends or straight sections. In this mode, it works like a normal yaw damper.

Operators who use their locomotives on very winding routes with very tight curves, such as those in Austria, Switzerland or northern Italy, benefit in particular from the active bogie steering system made by Liebherr.