The MR-73 is a type of subway car in the Montreal Metro, and they were built by Bombardier in La Pocatière, part of the Kamouraska Regional County Municipality in Quebec.
They came from a need to have more rolling stock to transport passengers to the Olympic Games in 1976.
Initially, they have been regularly in services on lines 2 and 4 since 1976 with the addition of line 5 when it opened in 1986. In 2008, they were replaced on line 4 by the MR-63, however, to compensate they would occasionally replace trains on line 1 until entering regular service on that line in 2016 as line 2 began using MPM-10 (Azur) cars. As of 2021, they are in service on lines 1, 4, and 5.After having been stored at the St-Charles Garage at Henri-Bourassa station for many years, they were eventually moved to Honoré-Beaugrand Garage once they were retired from line 2.
Trains consist of 6 or 9 car sets, depending on the lines. Line 1 and 2 are sets of 9, line 5 is sets of 6, and line 4 varies depending on the events or season. Also, trains used to be sets of 6 on weekends on every line, which isn't the case anymore. Theoretically, trains could always be split into groups of 3 as they were made 3 by 3 with each car at the extremities being equipped as a locomotive while the middle car isn't. Each car has 8 sets of doors, 4 on each side.423 total rail cars were acquired by the STM. They have a capacity of 160 passengers per car and up to 40 seats. They were built in lightweight steel alloy. They have rubber tires and use 750 volt DG guide bars. The exterior is light blue with a white line under the windows, and the interior was originally orange, white, and gray and since they were refurbished from 2005 to 2008, they are now blue and grey. Around that time, they also got new LED headlights.
The easiest way to differentiate them from MR-63 is by their rectangular headlights, and also by their traction motors that growl at acceleration, which produces the famous three-note sound (F, B flat, F). Since 2012, that sound is also heard before the door closes but this is done simply as a musical theme so people don't block the doors and isn't related to acceleration. They can be driven manually or with automatic train controls (the latter unavailable on line 4). However, doors always open and close manually. In the 1990s, they were the first trains to be equipped with automated station announcements, originally with Judith Ouimet's voice, followed by Michèle Deslauriers. Before that, operators announced the stations.