The first branch of the Montreal REM (Réseau express métropolitain) is now not scheduled to open until spring 2023. The light-rail train network was previously supposed to open between Montreal's Gare Central and Brossard on the South Shore by the end of 2022.

The company behind the project, CDPQ Infra, confirmed the news Friday morning after La Presse broke the story Thursday night.

"We fully understand the users who are eager to see the REM's service launch," CDPQ Infra President and CEO Jean-Marc Arbaud said in a press release.

"Our teams have worked hard in the last few months in a challenging environment to deliver a reliable network. Taking a few more months to deliver an experience that lives up to expectations was the responsible decision to make."

CDPQ Infra says obstacles related to supply chain disruptions, inflation and the labour shortage would have pushed the REM launch to the "middle of winter," a time the company says is "not optimal for the implementation of a new transportation network," especially given the changes to local bus networks that the REM opening will facilitate.

The South Shore branch is otherwise nearing completion, even if its trains won't run until the spring. A social media post coinciding with the announcement of the postponement shows the extent of construction progress, including gleaming new stations and track.

Two other REM branches, to Deux-Montagnes on the North Shore and across the West Island, are still on track to open by the end of 2024 (that's already a postponement).

A fourth branch to Montreal-Trudeau Airport still doesn't have an estimated opening date.