16.7 (nominal 50/3) Hz is central European standard used in Austria, Germany, Norway, Sweden, Switzerland since early- 20th century. German railway power supply has about 3 GW installed power (as of 2000) with a national 16.7 Hz grid, supplied by a combination of dedicated power plants, static and rotating converters and links to Austria and Switzerland. See Andreas Steimel, Electric Traction - Motive Power and Energy Supply, 2nd issue 2014 (Elektrische Triebfahrzeuge und ihre Energieversorgung)