Metrolinx has recently released new drone video for the Highway 401 / Highway 409 rail tunnels project that lets you peer into one of the tunnels, right under the cars travelling above.

The new tunnels will provide space for two more tracks in the future, supporting future two-way, all-day train service along GO Transit’s Kitchener line. A nearby track also carries Union Pearson express trains — and you’ll see a UPX train pass the site during this video.

Crews are excavating and constructing two tunnels, all while live traffic on 21 lanes continues along the two highways above.

A large orange tube at the top of the tunnels provides fresh air supply, which is constantly being pumped into both tunnels.

Metrolinx and GO plan to accommodate more passengers and increase service along the Kitchener line, as part of their GO Expansion Program (formerly “regional express rail”).