Toronto commuters have been in endless transit hell today after a four-hour shutdown between Jane and Ossington stations forced many to wait hours to board ridiculously overcrowded shuttle buses, with some residents even losing their jobs in the process. 

Service on Line 2 resumed around 10:16 a.m. this morning, but many were left to deal with overcrowded stations, cars as well as the overarching question: How did this happen?

Early reports indicated that a partial derailment of a train leaving Keele Yard caused the incident, and photos circulating on social media show a train that most definitely went off the tracks. 

That's not a minor derailment #TTC pic.twitter.com/MADqLmaLEw

— Cam Neil (@neilean) January 22, 2020

"This morning around 6 a.m., a subway train car leaving our Keele Yard partially derailed," said TTC Communications Advisor Hayley Waldman. "This impacted service on Line 2."

TTC spokesperson Stuart Green also tweeted a thread explaining exactly what happened. 

"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," he wrote.  

"Third and fourth cars have been decoupled for better access to derailed car (4th)."

A look at the train that partially derailed. The #TTC says train should be cleared with the hour and service should be up and running by lunch. @CityNews @BTtoronto pic.twitter.com/Q517QH9Lw6

— Tammie Sutherland (@citytammie) January 22, 2020

About an hour later, Green reported that the train had been rerailed and service would soon resume. 

"This was a bad morning for our customers traveling into and out of the west end and for that we apologize," he wrote. 

"Thankfully, subway derailments, even partial ones, are rare, but we commit to finding the root cause to avoid a repeat."

Wondering if this is where all the Line 2 problems started this morning. #TTC #line2 pic.twitter.com/3Q5LPBuhWz

— Karen-Luz "KL not kale" Sison 🙃 (@WordsByKLS) January 22, 2020

Photos of the incident show at least 27 TTC workers on the scene attempting to resolve the situation, though the TTC says the exact cause of the derailment is still under investigation. 

Image from the #ttc subway derailment this morning. How many TTC workers can you count? If you said too many you're probably right pic.twitter.com/hgLoSYKHum

— Craig 📷 (@IAmLensraptor) January 22, 2020

"Subway derailments are extremely uncommon," Waldman said.

"We’re conducting a very thorough investigation and assessment of the subway car, track and any other factors that could have been involved in the incident this morning."