Weight is becoming an increasingly important factor in trains and the chassis frame is a case in point. A massive, welded steel structure, the chasis frame bears all of a railcar body’s weight and transmits force from the wheels to the train, while withstanding heavy loads over a lifecycle of 30 years or more.
Innovations: Inventor of the Year 2016 - Prof. Christian Moser and Team
On Track to Lighter-Weight Trains
Radical new approaches to the development of rolling stock are extremely rare. Christian Karner and Radovan Seifried of Siemens Mobility, together with Prof. Christian Moser of Graz University of Technology, have succeeded in developing a new chassis frame that weighs only 845 kilograms instead of 1.5 metric tons – a reduction of almost 50 percent. For its achievement, the team was awarded the Inventor of the Year 2016 prize in the Open Innovation category.
Departing from Conventional Thinking
“Before us, nobody had dared a new concept for the chassis frame because it was difficult to imagine how a much lighter design could withstand these loads", explains Prof. Moser of Graz University of Technology. The specialist in structural durability and rail vehicle engineering has been collaborating closely with Siemens Mobility in Graz for 30 years. Siemens Mobility manufactures chassis for passenger trains, high-speed trains like ICEs, locomotives, streetcars and subway trains in the Austrian city. Together with design engineers Christian Karner and Radovan Seifried, Prof. Moser has formed a well-honed team that has been working constantly on improvements to chassis frames for years. “To be honest, ‘just’ making improvements had become a bit boring and I wanted to risk something radically new once more in my career,” says Moser with a laugh. His colleagues were immediately open to his suggestion. “It is extremely exciting to be able to go new ways in the design process,” Karner explains. And his colleague Seifried adds: “We had to depart from conventional ways of thinking, and that is a great challenge.”
The new chassis frame consists of a much stronger steel alloy than before. The inventors could only use selected welds that join the individual parts of its structure so firmly that they can withstand the jolting and vibrations generated at speeds of over 200 kilometers per hour. The team called established design forms for joining components into question. “When we had built the first prototypes and major components, we knew we were on the right track,” says Moser. But Siemens Mobility’s suppliers also had to change their way of thinking. Its engineers used to leave supplied parts unchanged and adapt new designs to them. “Now our suppliers have to manufacture their parts in line with the new concept," explains team member Christian Karner, “otherwise we couldn’t achieve the drastic reduction in weight.” During the design and development work, which lasted about a year, one innovation led to another.
The prototypes are tested thoroughly by the Structural Durability and Rolling Stock department of the Lightweight Construction Institute at Graz University of Technology. “Here, we are one of Europe’s leading institutes," Moser points out. Graz University of Technology is one of Siemens’ nine Centers of Knowledge Interchange (CKI). Siemens has worked closely with these leading universities in research and development for years. For example, Prof. Moser is also developing new measurement technologies together with Siemens, and these will be patented jointly. “Siemens and Graz University of Technology thus profit equally from the principle of open innovation," Moser says.