The TTC will be running buses instead of streetcars on Queen Street until at least Monday

TTC workers spent Wednesday afternoon and overnight inspecting the Queen streetcar tracks inch by inch — but still can't explain why 25 streetcars sustained damage to their supplementary brake systems.

"In order to allow crews to complete their inspections and get as many cars as possible repaired, we are planning for bus replacement service to continue until Monday morning or until such time as the track is declared safe for operations and we make significant progress on repairs to the damaged streetcars," said TTC spokesperson Stuart Green in a statement.

Streetcar service has been suspended on Queen since the brake damage was discovered on Wednesday afternoon, with about 90 buses brought in during peak times as a replacement.

Bus service on Queen will continue, the TTC says.

The damage, Green says, is to a supplementary brake system that hangs close to the ground on Toronto's new Bombardier Flexity streetcars. The issue has only been discovered on streetcars that travel the Queen route.

On all 25 of them, Green said, the damage is on the left side of the wheels, suggesting that each one hit the same obstruction or piece of problematic track.

Now that the Queen tracks have been cleared, inspection has moved to the tracks used by streetcars that are diverted from the main route, such as on Broadview Avenue and Shaw Street.

The TTC has added additional service to King Street and is encouraging commuters to take Line 2 of the subway until the issues are resolved.