Swiss railway clock

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Swiss railway clock
BahnhofsuhrZuerich RZ.jpg
A Swiss railway clock at Zürich HB
Manufacturer Mobatime
Type Electric clock
Display Analog
Introduced 1944
Movement Synchronous motor
A Swiss railway clock, in Lausanne railway station.

The Swiss railway clock was designed in 1944 by Hans Hilfiker, a Swiss engineer, together with Mobatime, a clock manufacturer, for use by the Swiss Federal Railways as a station clock. In 1953, Hilfiker added a red second hand in the shape of a railway guard's signaling disc.[1]

Since then it has become a Swiss national icon,[2] included among examples of outstanding 20th-century design by both the Design Museum in London and the Museum of Modern Art in New York City, and its clockface design is licensed for use on certain Apple devices such as iPads and iPhones.[1] Apple was initially accused of using the clock design without permission[3] Although the exact details of the licensing agreement are confidential,[4] it was reported that Apple ultimately paid Swiss national rail operator SBB about CHF 20M (about US$22.4M as of January 2014) to license the use of the clock design.[5] Apple later removed the design from its operating system with iOS 7.[6]

Technology[edit]

The clock owes its technology to the particular requirements of operating a railway. First, railway timetables do not list seconds; trains in Switzerland always leave the station on the full minute. Secondly, all the clocks at a railway station have to run synchronously in order to show reliable time for both passengers and railway personnel anywhere on or around the station.[7]

The station clocks in Switzerland are synchronized by receiving an electrical impulse from a central master clock at each full minute, advancing the minute hand by one minute. The second hand is driven by an electrical motor independent of the master clock. It requires only about 58.5 seconds to circle the face, then the hand pauses briefly at the top of the clock. It starts a new rotation as soon as it receives the next minute impulse from the master clock.[7]

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