The MR-73 is a type of subway car in the Montreal Metro, and Bombardier built them 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.
When the MR-73 was first introduced into service, they were originally found on Line 1 (Green) and later were introduced to Line 4 (Yellow). The trains would later leave Line 1 and move to Line 2 (Orange), sometime around the years 1983-84, when the Youville storage and maintenance facility was renovated and when Line 2 was extended to Du Collège. Line 5 (Blue) has always been served by MR-73 trains. 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 the new MPM-10 (Azur) cars. As of 2021, the MR-73 can be found 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 DC guide bars. The exterior is light blue with a white line under the windows, and the interior was originally orange, white, and grey 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 the MR-63 is by their rectangular headlights and traction motors that growl at acceleration, producing 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 is unavailable on line 4). However, doors always open and close manually. In the 1990s, they were the first trains equipped with automated station announcements, originally with Judith Ouimet's voice, followed by Michèle Deslauriers. Before that, operators announced the stations.