Tens of thousands of commuters will see their daily routines change dramatically starting in January 2020 as construction on the new REM line continues.
The Deux Montagnes and Mascouche train lines will once again bear the brunt of the delays, with each trip expected to be 20 to 45 minutes longer.
This is in addition to changes that begin later this month.
Last April the train service on those lines stopped entirely on weekends as crews worked on the REM tracks.
As of January 2020 train service on those lines will be truncated as four train stations will be closed for two years.
That's just a taste of the commuting difficulty to come, because at some point in 2021 the Deux Montagne line will shut down entirely as crews convert the tracks and stations to the specifications for the REM.
Commuters will have to transfer to shuttle buses that will take them to nearby metro stations so they can continue their trips downtown.
Transit officials expect that will add an extra 20 to 45 minutes per trip, depending on how far away people live from the city of Montreal.
Changes in March
Only one track as of March 25
The first changes are going to take place on Friday March 25, when construction will only allow one train at a time to go through Mount Royal tunnel.
On that day the train schedules on the Deux-Montagnes line and Mascouche will be adjusted, with trains waiting at the tunnel for up to five minutes before they can go through.
Two Friday departures from downtown for Deux-Montagnes will be eliminated, on top of the other weekend trips that have already been eliminated on those lines.
Bus service in Deux-Montagnes, Repentigny, and Terrebonne will have new schedules to match the trains.
In addition, as of May 21 the Canora and Mont Royal train stations will be eliminated and a new, temporary station halfway between the two will come into use.
Stations closed for conversion
From 2020 to 2022 four stations will be converted to use by the REM: Mont-Royal, Canora, Montpellier and Du Ruisseau.
With the Mont-Royal and Canora train stations closing entirely in January 2020 until some point in 2022, commuters who rely on those stations will instead be offered STM bus service or shuttle bus service to the Namur metro station and the Acadie metro station.
Those who normally board trains at Du Ruisseau or Montpellier will find shuttles or STM buses going to the Cote Vertu station.
People who ride the rails from Deux Montagnes or through the West Island will find the last stop on the train will be at the Bois Franc station, and transit officials plan to set up reserved bus lanes to ferry travellers to and from the Cote Vertu station.
Inside the Mount-Royal Tunnel: Excavation makes way for modern REM line
Deux Montagnes line closes entirely in 2021
In the middle of 2021 the Deux Montagnes train line will shut down from end to end as the track is entirely converted to use by the REM.
The final stage of construction of that spur of the REM is expected to last until 2023.
The plans are still being worked on, but commuters will have to rely on buses that will make their way to the Cote Vertu metro station -- and at some point in 2022, the Du Ruisseau REM station.
Transit officials are examining the possibility of setting up reserved bus lanes, changing traffic lights, and taking other measures to ensure commuting goes as smoothly as possible.
Mascouche train line will end at Ahuntsic
The REM means the Mascouche train line will no longer go all the way to downtown Montreal.
Instead the train's final stop inbound will be at the Ahuntsic station, and from there commuters will be able to take regular STM buses.
However transit officials are recommending people get off at Sauvé station and walk two blocks to the Sauvé metro station on the Orange line.
As an alternative, buses will be available to bring people from almost every station on the Mascouche train line to various stops on the Green line of the metro,
Public transit will always be available
The government is spending $192 million on the various transit measures as the REM gets built.
"I think it will be more accurate to see the bus going directly to the downtown city [instead of] being in their car waiting in the traffic," said Chantal Rouleau, the provincial Minister Responsible for Montreal. "We are putting mitigation measures and a lot of money in those mitigation measures."
Exact details of all these measures will be presented at the end of 2019.