Ontario Transportation and Infrastructure Minister Glen Murray attended a ceremony on Tuesday morning at the excavation site near Eglinton Avenue West and Black Creek Drive where construction will begin next month.
"We want to make rapid transit the easiest way to get to work because it’s the most environmentally friendly and it simply moves so many people, so much faster, so much safer,” Murray said.
The CBC's Trevor Dunn reported that the massive machines that towered above Murray will bore more than a dozen metres a day as they move east toward Kennedy station in Scarborough.
In total, 11 kilometres of the 19-kilometre line will be underground. It is expected to be in service by 2020.
Murray said the line will be more efficient in moving people than the roughly 50,000 vehicles that use the Don Valley Parkway on a daily basis.
"This line will run that many people in three hours," he said.
But the situation may only get worse in the short term for drivers who frequent Eglinton Avenue West, with construction in the area already causing delays and backups.
"The traffic is really, really a hassle," said Ron Leslie, who spoke to CBC News as he waited in his vehicle on Tuesday.
Bruce McCuaig, the president and CEO of Metrolinx, said "the biggest single traffic impact" would be while the stations are built, but a minimum of two lanes of traffic will "always" remain open.
'We have to move forward'
Trucks will move up to 80 loads of dirt out of the tunnel every day, and officials say the tunnel-boring machines will be deep enough that neighbourhood residents won't be able to hear the digging.
Despite being able to see the construction site from her backyard, Sonya Marques was in good spirits about having a major transit line right outside her door in the future.
"The traffic is a little bit heavier, but for me I think it's a great thing that it's coming here," she said. "You have to go through that process to get to the future. We have to move forward."
Metrolinx and Infrastructure Ontario, both provincial bodies, are picking up the tab for the $4.9-billion project. The line will be operated by the TTC.
The Eglinton LRT line is part of a larger light-rail transit expansion plan that includes the Scarborough RT, Finch West LRT, and Sheppard East LRT.
Dunn said once the project is completed, a trip from Black Creek at Eglinton Avenue West to Scarborough will take about 35 minutes.