Tunnelling starts on the Eglinton Crosstown West Extension

Today (April 11), Metrolinx marks a major milestone as tunnelling starts on the Eglinton Crosstown West Extension, the 9.2-kilometre extension of the Eglinton Crosstown LRT from Mount Dennis Station to Renforth Drive. Read on to see how these two tunnel boring machines came together and learn more about how they will dig the tunnels. Plus watch the new timelapse video.

Let the digging begin.

Rexy and Renny, the two tunnel boring machines (TBMs) for the Eglinton Crosstown West Extension, are starting their biggest journey yet.

After travelling across the globe – from a factory in Germany, across the Atlantic Ocean, to a port in Hamilton, before arriving at the tunnel launch site in Mississauga – it’s finally time to start digging transit tunnels.

Over the next 20 months, these two massive machines will work 20 metres below ground, digging twin tunnels that will stretch over six kilometres in length.

These tunnels will form a large part of the Eglinton Crosstown West Extension, which will expand the soon-to-be-completed Eglinton Crosstown LRT another 9.2 kilometres west, to Renforth Drive.

The two TBMs will start digging from the launch site near Renforth Drive and Eglinton Avenue West, moving 10 to 15 metres a day as they travel east to Scarlett Road, where they will be pulled out of the ground.

A close up of Renny, the first TBM that will start digging the tunnels. Rexy will follow about a month later
Renny, the first TBM that will start digging the tunnels. Rexy will follow about a month later. (Matt Llewellyn photo)

There, the route will run along an elevated section of tracks a few hundred metres east of Jane Street, before lowering back into another stretch of tunnels that will be part of another package of work.

Metrolinx is also working with the Greater Toronto Airports Authority and municipal partners to explore plans to further connect the line to Toronto Pearson Airport.

A timelapse video showing the TBMs from arrival and assembly, up until last week when they were still covered. (Metrolinx video)

Massive machines

  • The TBMs weigh about 750 tonnes each, about five times as heavy as a blue whale
  • They are each 6.58 metres in diameter, which is taller than a giraffe
  • At 131 metres in length, they are each a little over a quarter of the height of the CN Tower
  • To get the site ready to start tunnelling, a launch shaft was made that could hold the volume of 11 Olympic-size swimming pools
A tunnel boring machine, mid-assembly at the launch site. (Metrolinx photo)

How they work

As the TBM digs through the earth, the soil and rocks are removed by a conveyor belt and transported back to the launch shaft site. This material is then hauled off site to be properly disposed of.

The TBMs install tunnel liners as they go along. These give the tunnels their structure, and they’re critical in keeping them safe and keeping the TBMs moving.

A wide angle shot of the tunnel boring machines at the launch site
A wide angle shot of the tunnel boring machines at the launch site. (Matt Llewellyn photo)

The tunnel liners are made of reinforced concrete and are designed to support the earth and resist pressure from soil, rocks, and water that surround the tunnel.

As a TBM moves forward, it installs the precast tunnel liners using a special built-in device. The TBMs advance through the earth by pushing off the recently installed rings of tunnel liners using hydraulic jacks.

The precast tunnel liners for the Eglinton Crosstown West Extension are being manufactured by CSI Forterra Canada in Whitby – the same company that is supplying liners for the Scarborough Subway Extension.

A completed tunnel for the Crosstown, with tunnel lining rings bolted together to create the wall of the tunnel
A completed tunnel for the Crosstown, with tunnel lining rings bolted together to create the wall of the tunnel (Metrolinx photo)

The Eglinton Crosstown West Extension project will require 7,400 concrete rings for its twin tunnels.

What’s next?

While Rexy and Renny make their way east, construction is also starting at the extraction shaft near Scarlett Road and Eglinton Avenue West later this spring, with headwall construction at Martin Grove Road and Kipling Avenue also starting this spring.

For the latest information on the Eglinton Crosstown West Extension, visit the project website and follow the project on Twitter @EglintonWestEXT.

Story by Kimberly Murphy, senior advisor, Metrolinx subway program