Montreal Mayor Valerie Plante says she is "concerned" about provincial plans to expand the REM network.

The provincial government announced Monday that the Caisse de Depot's infrastructure wing, CDPQ Infra, is looking at expanding its electric train network to the eastern half of the island of Montreal.

This effectively cuts out the existing transit agency designed to analyze and operate transit in greater Montreal, the ARTM.

The REM's first stations are scheduled to open in 2021, and by 2023 there will be lines running from downtown Montreal to Deux-Montagnes, the South Shore, and Ste. Anne de Bellevue, but the CAQ government would like the REM to extend into Laval, to St. Jean sur Richelieu, and to the eastern section of Montreal.

Studying that proposal is expected to take about a year.

However Plante says that expanding the REM would be a bad idea because she believes it will overload the existing metro network.

She points out the Orange Line on the metro system is already packed during the rush hour, and will likely only get busier once the REM stations are operational.

She is calling for a pink line that would connect northeastern Montreal to the downtown core.