500,000 tonnes of earth, rock moved to clear way for Mississauga light rail transit line

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Published April 3, 2023 at 4:34 pm

The two tunnel-boring machines clear about 2,000 tonnes of earth and rock each day as they dig out route for light rail transit line. (Photo: Metrolinx)

More than half-a-million tonnes of earth and rock have been cleared out of the way to date as two massive tunnel-digging machines continue their daily chore of completing a key section of a light rail transit (LRT) line that will further connect Mississauga and Toronto.

Project leaders say the tunnel-boring machines (TBMs) shipped in pieces from Germany in late 2021 and tasked to help build the Eglinton Crosstown West Extension (ECWE) typically collect about 2,000 tonnes of earth and rock per day.

“All that material is taken out of the tunnel via conveyor belt, put into the muck pit (shown in Twitter post below) and eventually hauled away on trucks,” officials with Metrolinx, the provincial agency overseeing the major transit project, posted to Twitter.

The two TBMs have been working together daily since last July, a period of just over eight months. Prior to that, the first machine began its solo journey in April 2022.

When completed, the 9.2-kilometre ECWE will bring the Eglinton Crosstown LRT from Toronto west to Renforth Dr. in east Mississauga by 2030-31 and deliver some 37,000 daily rides to passengers.

A proposal to extend the ECWE an additional 4.7 kilometres from Renforth Dr. to Pearson Airport in Mississauga is also being strongly considered.

In the last 11 months, the two TBMs have been digging through dirt to carve out the underground portion of the ECWE.

“Renny,” the first TBM to start tunnelling, has moved 3.35 kilometres to date while “Rexy,” the second machine to go into the ground, has tunnelled 2.57 kilometes since late last July, project leaders say.

Tunnel work for the ECWE, which began last April, is expected to take about 20 months, according to Metrolinx. The TBMs are travelling eastward at a rate of 10 to 15 metres per day.

“Once they reach their destination just west of Scarlett Rd. (Toronto), they will be dismantled and removed from the ground through an extraction shaft,” say officials with Metrolinx, adding part of Eglinton Ave. needs to be moved a short distance south to make way for the extraction shaft. “This shaft is also the portal for where the trains will transition between the tunnel and the elevated guideway.”

When finished, the ECWE will operate underground from Renforth Dr. in Mississauga to just west of Scarlett Rd. in Toronto, where it will then transition to a 1.5-km elevated section that runs east of Jane St. before heading underground again and connecting to the future Mount Dennis Station.

Metrolinx officials noted in a project update late last year that the TBMs, in addition to their primary function, also hold the key to survival for workers should something go wrong and they not be able to exit the tunnels safely.

Each TBM holds inside of it a safety chamber, measuring nine metres long, 1.6 metres wide and two metres tall.

Meanwhile, Metrolinx officials said recently that they’re taking steps to get the line up and running ahead of schedule.

While the ECWE remains on schedule for a 2030-31 opening to passengers, officials told residents at an ECWE open house in March that as they seek to keep construction noise to a minimum, they may be able to move the project along faster.

Work on the ECWE hit a milestone early last month when one of the tunnels being dug out for the route passed the halfway mark to being completed.

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