After years underground, giant tunnel boring machines being pulled from Crosstown depths

The tunnelling work on Toronto’s Eglinton Crosstown Light Rail Transit (LRT) was completed in 2016 by four tunnel boring machines (TBMs). The city even knew their names – Dennis, Lea, Don, and Humber. Two were already taken out. Now Dennis and Lea are being pulled out as well.

Dennis and Lea – or parts of them – have seen the light of day again.

After being interned for years, deep underground Toronto, large sections of the two huge tunnel boring machines (TBM) have now finally been brought back to the surface. The pair – along with two sister digging machines that were also given nick-names – performed the majority of heavy tunnelling work along the Eglinton Crosstown light rail transit (LRT) route.

Then once their toiling was done, Dennis and Lea were left below, as work continued without their mechanical muscle.

Large sections of their machinery have now been lifted from their resting places. Rusted and worn, they’re looking a little less formidable than when the city watched as they were first lowered into the subterranean workplace with great fanfare.

The 6-metre long cutter head from one of the tunnel boring machines is lifted from deep underground.

The 6-metre long cutter head from one of the tunnel boring machines is lifted from deep underground. (Metrolinx photo).

The tunnelling work on the Eglinton Crosstown was completed in 2016 by all four tunnel boring machines. Two of them, Don and Humber, were dismantled and pulled out of the ground in 2017, but Dennis and Lea have been waiting quietly for four years while construction has gone on all around them.

This past weekend (March 7 and 8), one of their 10-metre high steel cutter heads – the mouthpiece that chews through the earth and stone – was removed, hoisted out by a very large crane, and then put on a truck.

This is the start of the end for the digging duo. Once both cutter heads are removed, the rest of the giant machines will be dismantled and taken out piece by piece.  That’s a lot of work to do, considering these machines are 81-metres-long and weigh 511,000 kg. To help you compare, the average car weighs around 2,000 kg.

Dennis and Lea were launched at Black Creek Drive in Spring 2013. They were drilling eastward, creating tunnels more than 5.7-metres in diameter, at a rate of 10 metres per day.

Dennis and Lea were launched at Black Creek Drive in Spring 2013. They were drilling eastward, creating tunnels more than 5.7-metres in diameter, at a rate of 10 metres per day. (Metrolinx photo)

During their time under the city, these impressive machines worked non-stop 24-hours a day, tirelessly moving mountains of earth to make way for future rapid transit. Now that work is done, the Eglinton Crosstown LRT is starting to take shape and Dennis and Lea can finally leave the site knowing the tunnels they created will carry millions of people in the decades to come.

Free again, where are they headed now? To dig giant flower gardens in some retirement home for aged construction giants?

No – their pieces will end up as scrap metal.

Story by: Scott Money, Metrolinx media relations advisor. With files from Erika D’Urbano, Metrolinx senior advisor, Rapid Transit.