Line 5, commonly called the blue line due to its color on the map, is the newest line of the Montreal Metro. Although it opened in 1986, its planning dates to much earlier as Snowdon station's construction began in 1975 and it was done with a cross-platform interchange where line 2 trains would share an island platform with a future line.
On June 16, 1986, the line opened, but even though Snowdon station was already built, they started on the Eastern side from Saint-Michel to De Castelnau. A year later, on June 15, 1987, Parc opened, and a few months after that, on January 4, 1988, the line went all the way to Snowdon, although for the first few months it skipped Acadie, who was the last station to open on the line on March 28, 1988. That latest extension also brought the metro to Outremont.5 stations are projected to be added in 2026 and would bring the metro to Saint-Léonard and Anjou.
Rolling stock has always been the MR-73 by Bombardier, but as opposed to other lines, trains are consisting of 6 cars instead of 9. That's why platforms will all have "Tête de train" or "Queue de train" written so passengers know where to stand. The exception to this rule is Saint-Michel, whose platform is only the length of 6 cars. That would be problematic if the MPM-10 trains were to be in service there as those trains cannot split. Also, line 5 is the only one where MR-63 never was in service, yet ironically, they did a one-day stay there on June 21, 2018, and it ended up being their last ride on the Montreal Metro.
The frequency of trains is 3 to 5 minutes during peak hours, 5 to 10 during non-peak hours, and 8 to 11 minutes on weekends.
Trains who need maintenance go to Youville workshop between Parc and De Castelnau.From there they can reach and switch to line 2 between Crémazie and Sauvé, just like they can at Snowdon station.
The majority of the stations have side platforms. Jean-Talon has stacked platforms and Snowdon has island platforms (with the other line).