Toronto's record-breaking subway mega-tunnel is already over 4km long
Canada's widest rapid transit tunnel is quickly taking shape as part of the over $10-billion Scarborough Subway Extension (SSE), a massive undertaking that will add three stops to the TTC's Line 2 Bloor-Danforth in place of the now-shuttered Scarborough RT.
The enormous subway tunnel will eventually span 7.8 kilometres between the current terminus at Kennedy and a new end-of-the-line stop at Sheppard Avenue and McCowan Road.
Under construction since 2021, the SSE project will break records with its almost 11-metre-diameter tunnel, carrying both directions of track within a single void, unlike the more common twin-tunnel method used on other modern transit lines in the city.
With a cavernous width large enough to comfortably house a three-storey building, the tunnel will become the largest such infrastructure in Canada upon completion.
And despite earlier hiccups in the tunnelling phase, the massive tunnel-boring machine carving out this new extension is now making impressive headway.
Dubbed Diggy Scardust in a nod to the David Bowie persona and the machine's dig through Scarborough, it has already etched out the majority of this record-breaking tunnel.
Metrolinx shared a new update on Monday morning, revealing that the dig for this new extension has crossed the four-kilometre mark, representing roughly 65 per cent of the tunnel's full length.
The most recent projections indicate the SSE could welcome its first passengers as early as 2033.
Metrolinx
