Dead-man's vigilance device
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A dead-man's vigilance device is a hybrid of a dead-man's control and a vigilance control. One such system is a system called "Sifa" ("SicherheitsFAhrschaltung", pronunciation: "sEEfaw", translated: Safety driving circuit), required by law to be installed in all Locomotives in Germany for single-person operation. It usually employs a foot pedal at the motorman's seat (with some additional hand buttons installed at cab windows which can be used alternatively) which must remain pressed down. Every 30 seconds (or less) the pedal or button must be released and reapplied. If the motorman fails to release the pedal within 30 seconds after pressing it down or releases it for longer than 5 seconds, he will be warned by an optical indicator for 2.5 seconds, then in addition by an audible signal (a buzzer or an automated voice calling "Sifa!" in ICE high-speed trains) for another 2.5 seconds, then the emergency brake will be engaged. This system eliminates situations where an ill or dead motorman falls on a dead man's switch, holding it down with his body weight. German motormen often learn to operate the Sifa pedal without having to think about it. The Melbourne variant of the Siemens Combino has also been retrofitted with a similar device and so have most of Melbourne's remaining W-class trams. The Melbourne variant of the Citadis, the C class, also has one, known derogatorily among its drivers as the "stupid clicking thing," referring to the resultant carpal tunnel syndrome.
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