The TTC says a private contractor working at street level has drilled through a concrete subway tunnel, causing damage and delays along Line 1 during the heart of rush hour.

The work was unrelated to the TTC.

The drilling happened at Lawrence station and subway service was suspended between Lawrence and St. Clair stations. Full service has since resumed, but the TTC says subways will be running at reduced speeds northbound through the affected area.

Line 1 Yonge-University: Regular service has resumed between Lawrence and St Clair. Shuttle buses will continue to operate to supplement service. https://t.co/L6Ep4V3GAI — TTC Service Alerts (@TTCnotices) October 22, 2019

TTC spokesman Stuart Green says engineers were on site to determine the extent of the damage and if there will be any long term structural impacts.

Around 90 shuttle buses were called in to deal with the afternoon rush hour.

The section of Line 1 was closed at 10 p.m. Tuesday for more permanent repair work, affecting travel options for the Raptors home opener.

As of 545pm, we have crews ready to plug and grout the hole. Service back in approx 30 mins with reduced speed of 15km/h through the area northbound. Southbound should be unaffected. We will close the line at 10pm for emerg repairs. Sorry, Raps fans. But safety first. — TTCStuart (@TTCStuart) October 22, 2019

Commuters wait for shuttle buses at Yonge and Lawrence. Mark Douglas/680 NEWS