A Toronto Transit Commission sign is shown in this undated photo. THE CANADIAN PRESS/Graeme Roy
The TTC says it is investigating a “software issue affecting a train supervision system” that led to a brief subway suspension on two lines on Thursday morning.
Service on Line 2 (Bloor-Danforth) and Line 4 (Sheppard-Yonge) was shut down around 10 a.m. and resumed around 30 minutes later.
“Operating safeguards remain in place as the investigation continues,” the TTC said in a update on X.
Officials also said the Automatic Train Control system on Line 1 (Yonge–University) was not impacted.