Commuters prepare to clench your teeth again. The TTC has issued its official notice and explainer video on the closure of the Spadina and Dundas intersection starting Monday.

That’s when the busy intersection will be closed for watermain work, followed by track and switch replacements.

Riders of the 510 Spadina streetcar will spend the summer on buses because the service won’t be back to normal until Aug. 31 when the TTC rolls out its new super-sized streetcars on that route.

The disruption will be worth it, promises TTC CEO Andy Byford on a video released via YouTube Wednesday.

“We recognize this is inconvenient for our customers and it is hugely disruptive for businesses,” he said.

But the new completely accessible, air-conditioned vehicles mark “the transformation of transit in Toronto,” said Byford.

Although the first of the new streetcars will roll out on the Spadina and Bathurst routes, it will be the end of the decade before they’re seen on all 11 downtown lines.

The watermain replacement is expected to take until July 28. During that period, the 510 replacement buses will travel in a single lane that will remain open on Spadina in each direction.

The 505 Dundas streetcar will continue to operate but avoid the Spadina intersection by traveling along McCaul to College and then Bathurst St.

Starting July 28, until Aug. 11, the intersection will be completely closed while the TTC replaces the track and switches there. The work that is supposed to be done every 15 years, was last undertaken in 1996.

When it happens, the TTC’s Spadina route will be split in north and south portions. The north end will run from Spadina Station to Baldwin St. and then loop back north to the station. Riders who want to continue south on Spadina will have to walk over to Sullivan St. from Baldwin and transfer to another bus.

A single lane of Spadina in each direction will re-open on Aug. 11 and remain open until the 30th. At that point the 505 Dundas streetcar will also return to its normal route.

But the buses will remain on the 510 Spadina route because the streetcar platform at Spadina Station will need to be retrofitted for the new vehicles.

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Last year the TTC replaced the track at Spadina and King streets. Two years ago it dug up the intersection of Spadina and Queen.

Track work still has the intersection of Queen St. and Broadview closed until July 25, although TTC spokesperson Brad Ross said there’s a chance the construction will finish early.