The New Air-Free Siemens Brake System

In close collaboration with Siemens Liebherr developed and produces a compact, closed, electrohydraulic brake actuator including all the components necessary to build-up and release the brake force as well as local control. Unlike the conventional pneumatic brake, with the new air-free Siemens Brake System the control of the brake is fully electrical (brake-by-wire), which means that all piping and all pneumatic components for controlling the brake can be eliminated.

The brake actuator is integrated in the bogie in the same installation space and has the same mechanical interfaces as the conventional pneumatic brake caliper. This brake actuator meets the highest safety requirements and Safety Integrity Levels up to SIL4 and also the latest rules and regulations for safety verification. The brake actuator is derived from the technology that Liebherr developed for aerospace flight control actuation applications.

Siemens Mobility is implementing the new brake technology for the first time on the X-Wagen metro project. Wiener Linien will be the first transit authority in the world to benefit from this system, both in conventional operation with a driver and later in automated operation on the new U5 Line.