Great progress is being made by the Toronto Transit Commission as it builds the new Toronto-York Spadina Subway Extension, a six station, 8.6 kilometre line that will extend from the existing Downsview Station and will end at Highway 7 west of Jane Street.
The tunnel boring machine cutterhead
Last year, utility relocation work was completed in area neighbourhoods to make way for the station and then tunnelling began for the new line. All four tunnel-boring machines are now headed toward the Keele Finch area and will arrive at different points in time at the extraction shaft.
Holey and Moley, named by York history Professor Thomas Cohen (right), are boring the twin tunnels north from the Sheppard West Station site and both machines are now under Keele Street, headed to the extraction shaft located in the middle of Keele Street, just south of Finch Avenue West. Yorkie and Torkie, who were named by Rosa Rinella of Vaughan, Ontario, are boring south from Steeles West, through the York University Keele campus and are headed toward the extraction shaft on Keele Street, located just north of Murray Ross Parkway.
The four tunnel-boring machines will do most of the tunnelling for this extension. The machines are so large that each had to be delivered in pieces to the launch shafts at the Sheppard West Station and Steeles West Station construction sites.
The machine cutterhead excavates the tunnel using discs and scrapers that crush and remove soil and debris. A conveyor removes debris from the tunnel using rail cars. Each machine moves very slowly, advancing up to 15 metres per day, removing earth and lining the tunnels with concrete “tunnel liners”.
There are two extraction shafts located on Keele Street. The first extraction shaft is located south of Finch Avenue West and the second is located north of Murray Ross Parkway. Holey and Moley, along with Yorkie and Torkie, will be removed using the extraction shafts – a process that will take place over the next year. After the machines are removed, the shafts will be used to deliver subway equipment to the tunnels.
Over the next few months, Keele Street northbound, north of Finch to Murray Ross Parkway, will remain closed. The tunnel-boring machine Holey will be removed from the extraction shaft on Keele Street south of Finch Avenue West, followed by Moley in late spring. Excavation of the subway stations will get underway. Installation of shoring and tie-backs in the station box will take place. Building materials and supplies will be delivered and large concrete pours will be started. Several large tower cranes will be erected.
Transit delays can be expected during peak times on the 36 Finch West, 107 Keele Street and 41 Keele Street buses. Some bus stops may be temporarily relocated for construction. Advance notices will be posted to alert riders of the relocation.
Images and technical information provided by the Toronto Transit Commission.