TORONTO -- The TTC says subway service has resumed on Line 2 between Jane and Ossington stations after a partial train derailment in the midst of morning rush hour Wednesday.

The transit agency said that all trains had stopped travelling between the seven stations at around 6:08 a.m. after crews reported a partial derailment of one of the middle cars of a train, not in service, that was leaving Keele Yard.

TTC spokesperson Stuart Green told CTV News Toronto Wednesday said the train was attempting to leave the small yard, which normally stores five to six trains, in order to get into service for the day.

Our crews are reporting a partial derailment of one of the middle cars of a train that was leaving Keele Yard. It was not in service. Currently assessing cause and rerailing plan but this will be a few hours to resolve. 100 shuttles ordered Jane to Ossington. GO protocol below. https://t.co/H6B48gVlNt — TTCStuart (@TTCStuart) January 22, 2020

He said the first three cars behaved normally but the fourth car "sort of jumped the rail a little," and added that the car needed to be placed back on the rail so that they could pull the car out.

"It was our busiest time of day and it meant tens of thousands of people were inconvenienced," he said.

"We understand that was hugely problematic for them, we have to offer our apologies and commit to do better, and try to find out exactly what happened so we don’t have a repeat of that."

Before service resumed at around 10:20 a.m., almost 100 shuttle buses were ordered to assist passengers, Green said, adding that the TTC had to pull buses from other routes in order to accommodate the crowds.

Officials urged commuters to use their TTC fare to board GO Transit vehicles at various stations in order to alleviate the pressure.

Commuters formed long lines to board the shuttles at each station during the morning rush. Some people complained on Twitter that they waited over half an hour to get on a bus.

@TTChelps how are your buses already completely full??? The 26 just blew past me at Dupont and Bartlett at 6:53 and now I’m late for work waiting in the freezing cold. This is so unacceptable I can’t even rely on the TTC to get to work. — Blackout, Tequila (@tequilablack0ut) January 22, 2020

No TTC service between Jane and Ossington pic.twitter.com/K2lAIpIJyH — Pete (@Pete_Nguy) January 22, 2020

Green said the TTC estimates that more than 50,000 people normally go through those closed stations. He said there is usually a lag when incidents like this one happen during the busiest time of the day.

"When these things happen at the busiest time of day, it’s that perfect storm, we have to apologize for this morning, we know it was hugely inconvenient but we will look at how we handled that," he said.

"We will do a lessons learned on both the incident itself and how we handled it."

Green said that "thankfully" subway derailments, even partial ones, are rare.

Hey Toronto City Council? Can we properly fund the TTC please? I need to get to work. pic.twitter.com/DrMJBOa682 — erin (@why_erin) January 22, 2020

Toronto police said that Bloor Street West was temporarily closed between Royal York Road and Jane Street because roads were congested with pedestrian traffic due to the subway closure. The road was only open for TTC shuttle buses, but has since reopened.