Rexy and Renny’s incredible journey

CAPTION: TBMs Rexy and Renny have completed the tunneling of the ECWE (Metrolinx photo)

Since Rexy and Renny – the twin tunnel boring machines (aka TBMs) – completed their 6.3-km dig of the Eglinton West Crosstown Extension, people have been asking questions about them. Their incredible underground journey extended all the way from Renforth Drive in Mississauga to Scarlett Road in the Rexdale neighbourhood of Etobicoke. Here are some answers to commonly asked questions about these massive twins.

Are TBMs essentially big drills?

They are much more! TBMs have multiple jobs. To drill and excavate, at the front of each TBM is a cutter head, which chomps through the earth and rock. Soil is excavated all the way up to the surface. In addition, Rexy and Renny also assemble the concrete tunnel liners as they dig. Each liner segment is fastened into place by the TBM, then grout is injected behind each segment, forming the tunnel wall. They collect approximately 2,000 tonnes of earth daily, which is transported out to the surface. The TBMs travel 10-15 metres in a typical day. In total, Rexy and Renny installed over 52,000 segments to build 7,433 support rings.

How big are they?

Each TBM weighs about 750 tonnes (seven times the weight of a blue whale) and are 131 metres long. They contain a control room, and crews work inside the TBMs to guide them along their way.

Now that Rexy and Renny are finished digging, what happens to them?

After they emerged from their tunnels they are dismantled, and lifted out of the shaft, with their parts put into storage.

What’s next?

Crews are now working at the extraction shaft –the future portal for where the light rail vehicles transition between the tunnel and the elevated guideway. This 1.5-kilometre elevated segment will run between Scarlett Road and Jane Street.

A second tunnel will be built eastward from Jane Street to Mount Dennis Station, linking the extension to the Eglinton Crosstown LRT line. Since this second tunnel will be built quite differently, neither Rexy and Renny – nor any TBM – will be needed. This eastern underground segment will be constructed using a ‘sequential excavation method’ which is more suitable to dig the relatively short tunnel needed to connect the extension to Crosstown LRT service at Mount Dennis Station.

Learn more about the Eglinton Crosstown West Extension project!