A cleaner found a suspicious package on a subway train parked at Kennedy Station.
The package had a note that indicated it might be a bomb.
The station was subsequently evacuated as police investigated.
The TTC tweeted that shuttle buses were operating in both directions between Warden and McCowan stations, though they were not servicing Kennedy Station during the closure.
Sgt. Lou Gibb said the package was deemed to be a threat and was detonated, though it turns out it did not contain any explosive materials.
"There was no bomb inside the package," Gibb told reporters outside Kennedy Station on Tuesday evening.
Gibb said the incident wasted the time of citizens, TTC employees and the police.
"Suffice to say it was a prank, it’s inappropriate," he said.
Investigators are now trying to determine who left the package on the train.
The station reopened late Tuesday evening after being closed for several hours.