Under 21 lanes of Highway 401 and 409 traffic, Metrolinx has started the construction of a GO Transit tunnel to add new tracks to the Kitchener line.

The construction will create two single-track tunnels, just two metres north of the existing GO Transit tunnel.

Once the project is complete, there will be two-way, all-day GO service every 15 minutes on the line, with additional service during peak hours.

I’ve never been so excited about a tunnel. We still have a ways to go and many more projects to complete, but this is good news. — b r u c e 🇨🇦 (@PassTheBruce) July 26, 2019

The “twin tunnel” will span 176 metres long, beneath “one of the busiest sections of highway in North America,” according to Georgina Collymore, Metrolinx's senior advisor.

She says the work shouldn’t impact highway traffic.

@Metrolinx he has a point about the tunnel. It's kind of silly how long it's taking https://t.co/00ozPrN95P — George Simopoulos (@MrGeoSim) July 26, 2019

One significant change has already resulted from these construction plans. The Etobicoke North GO Station is closing down. Major changes would have had to be made to the station in order for it to remain open.

A new station will open at Highway 27 at Woodbine racetrack. This new station will be privately funded by Woodbine Entertainment.

The tunnel construction is projected to be completed by 2021 and has been valued at $116.9 million.