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The MR-73 is a type of train used on the Montreal Metro's Orange and Blue lines, with a minority of said trains being used on the Green Line. == Description == In 1974, the Commission de transport de la Communauté urbaine de Montréal (CTCUM), the predecessor of the STM, awarded the contract to build 423 MR-73 cars to Bombardier Transportation.〔(STM company timeline ). Société de transport de Montréal. Retrieved 2013-02-13.〕 The MR-73 cars were manufactured from 1974 until 1980 and first entered service in 1976. The MR-73's original interior featured orange-and-white seats arranged such that in each third of the train there were two double sets of transverse seating and four single seats near the doors in longitudinal formation,〔(Montreal Metro- Arriving train at Lionel-Groulx, Orange line ). YouTube. May 22, 2006. Retrieved 2013-02-13.〕〔(Montreal Metro- Blue line from Jean-Talon to De Castelnau ). YouTube. May 22, 2006. Retrieved 2013-02-13.〕 which were removed during the 2005–2008 refurbishments and the seating arrangement subsequently modified. The MR-73 is the second generation of high-performance Metro cars, identified by rectangular cab headlights, blue and dark orange interiors, 174 kW (233 hp) traction motors that growl while accelerating out of a station, side vents, and a unique three-note sound signature when the train pulls out of a station. The Mean Distance Between Failures (MDBF) for the MR-73 exceeds 200,000 mi (322,000 km) in 2004. The initial rate of acceleration of the MR-73 model is 1.43 m/s2 (4.7 ft/s2) (5.2 km/(h·s) or 3.2 mph/s). The three-note sound is produced by traction motor control equipment called a "current chopper", which is used to control and power the motors on the train in stages without incurring a power surge. It does this by modulating the current in 5 consecutive stages (90, 120, 180, 240 and 360 Hz), the latter 3 being normally audible. A prototype for the current chopper was built by the Canron company using a Jeumont original design in the early 1970s on an MR-63 train. Two of the three elements of this "Jeumont Train" are operated on the Green Line among rheostatic-started MR-63s. One is much louder than the other. They are the only two to exhibit the whole five-note audible signature in normal operation, even though it is possible to hear them during longer than usual starts on regular MR-73s. These notes are the same as the first three notes of Aaron Copland's "Fanfare for the Common Man", one of the musical themes for Expo 67, though this is apparently just a coincidence. Some MR-73s originally sported murals of Montreal at the end of the cars, however these were damaged by vandalism and removed long ago. The MR-73 has a different electrical braking system than the MR-63 to assist friction braking. The MR-73's current chopper recuperates energy when in braking mode, turning traction motors into generators and sending a regulated current back into the traction power supply for other trains to use. Electrical braking is most effective when one train draws power while starting while another train at a different location sends power while braking. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「MR-73」の詳細全文を読む スポンサード リンク
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