Efficient and Quiet: Running Gear for Trains

2007.07.06 | Rail travel is about to become quieter and more environmentally friendly. That’s because Siemens has developed the first concept to combine drive, running gear, and brake technology. The innovation also dispenses with components that generate noise and are particularly subject to wear and tear, such as a gearbox. What’s more, the compact drive system is 20 percent more energy-efficient than its predecessor. As the research magazine Pictures of the Future reports, Siemens is currently testing the system in the Munich subway.

The motors that power today’s rail vehicles run continuously at high rpms, so a gearbox is needed to convert this power to the slower-running wheels, and the resulting friction losses increase energy consumption and wear. The open-circuit air-cooled asynchronous motors most commonly used today feature many roller bearings and rubber parts that require regular maintenance.

Now, Siemens Transportation Systems (TS) has introduced Syntegra, a rail drive system characterized by a degree of integration unrivaled worldwide. The experts have integrated not only the running gear and brake system into the bogies of the Munich subway trains, but also a gearbox-free direct drive. Aside from two roller bearings, which simultaneously serve as wheel set bearings, the motor contains no parts that are subject to wear, thereby saving costs and increasing service life. An enclosure protects the motor’s interior from dirt and moisture and reduces noise to a minimum — because a traction motor ventilator is no longer needed, for example. The motor technology, which relies on high-performance permanent magnets, has the advantage that it is fail-safe, and the motor can be used as a safe electric second service brake.

Syntegra also is 15 percent more compact and 30 percent lighter than its predecessor. That means energy efficiency can be increased by as much as 20 percent. Used in a four-car subway train in typical service, Syntegra can deliver annual savings of 340,000 kilowatt hours — the equivalent of the energy consumed in one year by about 100 households.

Even before the series production stage, the running gear has demonstrated its impressive performance: In June the TS experts were honored for their fully scaleable system with the “Intelligence for Transportation and Logistics” Innovation Award presented by the Center for Transportation & Logistics Neuer Adler e.V. in Nuremberg.