The crews building tens of kilometres of support structures for the new light rail system that will connect Montreal's suburbs to the downtown core are using advanced techniques to hasten construction.

This week construction crews showed off a massive crane called a launching gantry installed at the site of a future REM station in St. Laurent.

Using the gantry, crews can hoist a 50-tonne precast concrete section and attach it to the existing structure within a matter of minutes.

Stefan Balan is leading the construction of the spurs that will reach Trudeau airport and Ste. Anne de Bellevue.

"This was chosen after a very meticulous process of analysis so given the fact that we are building a very long alignment, a 13.4-kilometre bridge if you want, from here [in St. Laurent] to Ste. Anne de Bellevue, this method proved to be the optimal one," said Balan.

Using traditional building techniques it would have taken about three weeks just to do each section of the structure.

Instead Balan said that by using the gantry currently in St. Laurent, and a second one that is slowly heading west from Pointe-Claire, it should take about three weeks to build the entire support structure consisting of more than 4,000 concrete segments out to the Ste. Anne station.

The work Balan is doing will be highly visible throughout the West Island, but most of the work being done on the REM this year will be underground, including digging a 3.5 km tunnel underneath Trudeau airport.

This summer crews will begin assembling the boring machine, and it will start digging in the fall.

However on the South Shore, the test tracks between the Panama and Du Quartier stations in Brossard should be ready in three or four months. Those tracks will be tested next year and should be operational in 2021.

"What we're building right now is not just an infrastructure project like the Champlain Bridge, like the Turcot Interchange, we are building a new system," said REM spokesperson Jean-Vincent Lacroix.

The entire REM is scheduled to be completed by 2023.

Amanda Kline contributed to this report