Will the capacity be increased on the Deux-Montagnes line?

Yes, the capacity of the Deux-Montagnes line will be much higher.

REM cars are smaller than MR-90 cars, but run much more frequently due to the high frequency of the light rail metro line. Thus, the REM provides a higher capacity per hour and per day.

For example, during the morning peak period (from 6 to 9 a.m.):

With the REM
Maximum capacity of a metro: 780 passengers
Number of departures from 6 to 9 a.m. : 54 departures (36 at Deux-Montagnes, 18 at Bois-Franc coming from the airport)
780 x 54 = 42,120 passengers

With a MR-90 train
Maximum capacity of a train: 1,900 passengers
Number of departures from 6 to 9 a.m.: 9 departures (6 at Deux-Montagnes, 2 at Roxboro-Pierrefonds, 1 at Bois-Franc)
1,900 x 9 = 17,100 passengers

To learn more, read our article: The REM, seating and capacity