MONTREAL -- Construction is moving along for Montreal's REM light-rail system, but one aspect of it has some people concerned: its newly announced expansion to the east.

"We're really worried," said Christian Martel of the Regroupement Citoyen REM Ville-Marie, which represents hundreds of downtown residents who live along Rene-Levesque Blvd. and Notre-Dame St.

The REM's lines ot the east and north end of Montreal are going to be built along those streets, above ground, which the group says isn't a good idea.

"My condo is literally on Rene-Levesque, so probably the tracks will be 15 feet from my bedroom window," said Martel.

"So it's worrisome, because trains are going to go every four minutes in one direction."

One leader even said it'll create an "urban scar."

The MNA for Hochelaga-Maisonneuve, Alexandre Leduc of Quebec Solidaire, said Montrealers should recall the building of Highway 40, which "dismantled somehow a neighbourhood in two," he said.

"It's a frontier inside the city, and we don't like... this kind of urbanism," he said. "And we are afraid that the REM de l'Est might provoke those kinds of scars."

A new petition on the National Assembly's website is now asking for the REM to be buried underground, and that residents be consulted.

"Everyone in the East of Montréal are happy about the idea of getting new options on public transportation. Everybody. But this happiness is not an excuse," said Leduc.

The current expansion plans will cost $10 billion. It's the largest amount ever invested in a public transit project in Quebec, the province says.

Making it underground would certainly add to those costs, though it's unclear how much.

One of the project leaders at the Caisse de Depots et de Placements, which is in charge of the construction, would only say that it will hold public consultations about its plans for that area in the coming weeks.

Quebec's Ministry of Transportation said it had no comment on the matter.