Teichmann wanted to realize a completely new bogie, lighter and more compact than what was available, but also suitably robust for heavy loads. He began by positioning the wheelsets behind the wheel disk. Bogies on conventional running gear are outside of the disks, because it is important for them to be easily accessible for frequent lubrication of the bearings. Thanks to today’s modern bearings and lubricants, however, maintenance intervals have become longer, so the accessibility question has become less crucial.

While the positioning of the bearings on the inside opened up new perspectives, there were still many problems to be solved at first. A conventional drive complete with brake system takes up so much space that the wheelset gauge and the frame structure, the two factors that determine the size of a bogie, are essentially fixed. This doesn’t worry Teichmann: “I just assumed that sooner or later there would be a new drive system, and kept on developing, simply ignoring the restrictions resulting from the conventional motor.” Teichmann was aware that his colleagues in Erlangen and Nuremberg had started to work out ideas for a new drive.

Then, at an inter-Group development meeting several years ago, Dr. Andreas Jöckel reported on his concept for a three-phase direct drive. “It was a perfect match: He had the motor, and I had the bogie.” Using the direct drive, which sits right on the axle, eliminates the need for a number of components, including gearboxes, clutches, and rods (see Inventor of the Year 2007, Dr. Andreas Jöckel, Siemens Automation and Drives). A decision was reached to work closely together to coordinate further development, and additional synergy effects were found, such as the merging of the wheelset and motor bearings: the Syntegra integrated motor bogie technology was born.

A wheelset gauge of 1,600 millimeters is sufficient for the new motor bogie, while today’s subways require up to 2,500 millimeters. The Syntegra bogie frame consists of two longitudinal beams and a cross beam, which are flexibly connected. Until now, rigid frames have been the norm. Instead of transmitting guidance forces via the frame articulations, Syntegra relies on the direct body-to-bogie link of the wheelsets and a cross beam, by means of a wishbone. This ensures very precise guidance of the wheelset. In all, the new running gear is approximately two tons per bogie lighter than today’s technology. That the development deserves to be called a breakthrough is clearly confirmed by the energy balance: A four-car subway train using the bogie, for example, can transport about 200 passengers more than a conventionally equipped train, with the same level of energy consumption. Viewed from another perspective, the energy saved would be enough to supply 113 one-family homes with electricity.

Teichmann is particularly proud that all the improvements were achieved with the materials that have always been used for building bogies — steels. “We didn’t use any new miracle materials, no additional electronics or other hocus pocus. The concept simply does the job it was designed to do.”

And that, Teichmann says, will also convince the rail operators. “The costs savings aren’t exactly nickels and dimes.” Nevertheless, such a development advance requires comprehensive testing, and a prototype is now being operated in a testing phase in the Munich subway system.

The very fruitful collaboration of all the developers was possible due to many factors, says Teichmann. “Generosity” is a word that quickly comes to mind for him: the sharing of ideas, comparing results and findings with one another, and being willing to travel for the sake of the project. And that’s why all the colleagues he had contact with — and especially the managers who provided the “breathing room” needed to succeed — contributed to the invention of Syntegra, Teichmann emphasizes. He predicts a very bright future for rail vehicles — high-speed and regional trains alike: “Let’s face it. It’s an elegant solution for mass public transportation.” With this in mind, Teichmann wants to continue to dedicate his creativity to bogies, even while working fewer hours now. He’s reserving two afternoons a week these days to spend with his two small children. “With a little discipline and understanding in the workplace, it’s no problem to cut back a few hours and still do productive development,” says Teichmann. He has 22 inventions made which led to a lot of patents.

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