After four years of sitting idle, the two machines responsible for digging six kilometres worth of subway tunnels under downtown Toronto have been decommissioned and disassembled.

The 10-metre-long machines, dubbed Dennis and Lea, were lowered beneath Eglinton Street at Black Creek Drive in 2013. They then spent the next three years digging parallel tunnels for what will eventually become the western portion of the underground section of the $5-billion Eglinton Crosstown light rail project.

Once the machines finished their routes, however, they had to hold in place until such time as two companion tunnel boring machines—Don and Humber—could complete excavation of the Eglinton Station at 20 metres underground. That took four years.

Work began on decommissioning Dennis and Lea in early March. At 400 metric tonnes in weight and 6.5 metres in diameter each, the machines could not simply be hoisted out of the ground. Crews had to disassemble the machines and hoist their component parts out of a shaft just west of the intersection of Yonge Street and Eglinton.

The machines have reached the end of their service lives. Their component parts cannot be reassembled, and will be sold for scrap.

Work continues on the Crosstown LRT project, as the project meets the criteria of essential infrastructure under authority from the provincial government. The line was due to open in the fall of 2021, but it appears increasingly likely to be delayed to the middle of 2022.

A time-lapse video supplied by Metrolinx shows the decommissioning and removal work in progress.