A last tap of the hammer from Premier Kathleen Wynne and other dignitaries earlier today marked the completion of the rails for the long-awaited northwest extension of the Toronto Transit Commission's Line 1 (TYSSE) to Vaughan.

Ceremony to celebrate completion of track for TTC subway to Vaughan.Premier Wynne and VIPs make the ceremonial last taps to complete track installation, image by Jenna Muirhead/MTO

To coincide with this latest milestone, almost eight years after construction began, the TTC released a time-lapse video of the first end-to-end journey along the 8.6km line.

 TTCThe route of the Toronto-York Spadina Subway Extension Source: TTC

Wynne was also joined by Toronto Transit Commission (TTC) CEO Andy Byford, TTC Chair John Colle, Ontario Transportation Minister Steven Del Duca; Adam Vaughan, MP for Spadina-Fort York, and York Region Chairman and CEO Wayne Emmerson, four of whom are pictured below in front of the future Grimshaw-designed Vaughan Centre Station.

Ceremony to celebrate completion of track for TTC subway to Vaughan.Andy Byford, Josh Colle, Kathleen Wynne, Steven Del Duca, image by Jenna Muirhead/MTO

Josh Colle, the TTC's chair, assured reporters that the TYSSE project remains on target to open in December 2017, though this is a year and a half after its original planned finish. He added that the extension's six stations were 90 percent complete.

Ceremony to celebrate completion of track for TTC subway to Vaughan.Descending towards track level at Vaughan Centre Station, image by Jenna Muirhead/MTO

The TYSSE is expected to cost $3.2B, $400M more than originally budgeted. The Ontario Government contributed $870M of the total, with the remainder coming from the Toronto, York Region, and Canadian Governments. York Region's contribution come as the subway system expands beyond Toronto's boundaries for the first time. The extension is expected to remove 30 million car trips annually from the roads, while providing 36 million new rides on the line.

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