Source: Siemens post

ERLANGEN, Germany — The following interview with Robert Steinfelder, Vice President Siemens Brakes, Siemens Mobility GmbH and Jens Lichterfeld, Senior Expert Brakes, Siemens Mobility GmbH, was posted on the company’s website as a means of describing its new airfree brake system.

The new airfree brake system is the first fully electrically controlled friction brake to be implemented in rail vehicles (brake-by-wire), therefore it‘s also called electric friction brake system. The brake system in the vehicle operates completely independent of compressed air. Besides various technological benefits, the new brake reduces vehicle weight and the vehicles are faster ready for operation, as Robert Steinfelder and Jens Lichterfeld told us in this interview. Both are significantly responsible for the development and market launch of the innovative Siemens Brake.

Mr. Steinfelder, Siemens Brakes has been successfully implementing pneumatic brake systems in a variety of Siemens Mobility projects for a number of years. With this solution, you’ve now added a new and innovative brake system to the MoComp portfolio. How did it come about?

Robert Steinfelder: Since 2003, Siemens Brakes has been an independent department within Siemens Mobility and works closely with the vehicle engineering and commissioning of Rolling Stock. Starting with the first metro project, the V-Wagen in Vienna, we’ve been the in-house system supplier for all metro projects in the past 18 years.

During this time, we’ve been able to acquire a lot of experience with pneumatic brake systems and we have implemented additional synergies across systems, seeing things from a train manufacturer’s perspective. After years of optimizing the conventional air brake, from our point of view, it was time for something new, a technological leap, a genuine innovation in the field of brake systems for rail vehicles.

And with the technological leap you refer to the new airfree brake system, right? Mr. Lichterfeld, what is this exactly?

Jens Lichterfeld: Unlike the conventional pneumatic brake, control of this brake is fully electrical – “brake-by-wire” – which means that all piping and all pneumatic components for controlling the brake can be eliminated. Brake force is generated right in the brake actuator. We worked with Liebherr, a highly experienced company in the aerospace sector, to develop a compact, closed, electrohydraulic brake actuator including all the components necessary for pressure build-up and release as well as local control. 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.

The pneumatic brake has been used in rail vehicles for 150 years. Is there any particular reason to get rid of it in the future?

Robert Steinfelder: Basically, there’s no reason to get rid of the pneumatic brake. Pneumatic brake systems have been proven successful for decades, experienced continuous improvements throughout this period and will continue to be used in rail vehicles in the future. Our goal for this technological leap was to generate a unique selling point for Siemens Mobility, because we believe that the pneumatic brake system has reached its limits in terms of optimization.

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