The TTC says a train on the Scarborough RT had to be evacuated of all 129 passengers after it was damaged Friday morning, forcing the full closure of Line 3 for nearly four-and-a -half hours.

TTC spokesperson Stuart Green said the transit commission was first advised of the power off situation shortly after 7:30 a.m. The train was approaching Midland Station when something happened to the piece of metal that connects the vehicle to the third rail, resulting in damage to both the train and the power rail, Green said.

What exactly happened is still under investigation. The TTC said service resumed around noon.

Once transit crews ensured the power was shut off, they walked passengers off the train, Green said. No one was injured in the incident.

The damaged train is now being inspected in the TTC garage. 

The TTC told CBC Toronto it is currently working to extend the life of the Scarborough RT, and that includes updating each train on the line. 

TTC repairs

TTC spokesperson Stuart Green said work is ongoing to keep the RT running smoothly until the Scarborough subway is built. (Giordano Ciampini/Canadian Press)

"We know of course that the Scarborough subway is being built, so we had to as a result of that come up with a plan to keep the RT running," Green said. "This [incident] talks to the importance of doing that."

"This line is about 40 years old now so there are things we need to do to keep it running."

Green said it's unclear whether or not the train that was damaged is one of the vehicles that had been updated. That will come out in the TTC's investigation.

He said most of the work has been proactive, and that the transit agency has had fewer service interruptions within the past year because of it.