This article lists major incidents of the Toronto Transit Commission (TTC) since 1954, such as accidents and other notable unplanned events.

Accidents and other incidents 1900s

On March 27, 1963, a six-car Gloucester-series subway train was completely destroyed by fire. This occurred on a spare track near Union station, after the few remaining passengers were evacuated. In 1974, the TTC union went on strike shutting down the system for 23 days, resulting in traffic jams. Transit service resumed on September 4 after 78 percent of workers voted to return to work given a provincial threat to force an end to the strike. An arbitrator granted union members increased wages, more vacation days and an exact-fare policy for service routes that was to start no later than October 1, 1975. On November 7, 1975, 16-year-old schoolgirl Mariam Debra Peters was attacked in St. Patrick station and died a few days later. After a police audit in 1982, this incident led to sections of the respective platforms of St. Patrick and Queen's Park stations being sealed off from the public, along with the installation of "prison" bars at the south end of Museum station to allow for ventilation and storage. In August 2022, construction began to replace this section of Museum station with a second exit, which opened in May 2024 to the public with the automatic fare gates at platform level. 1975 Scarborough bus-train collision: On December 12, 1975, a TTC bus travelling east on St. Clair Avenue collided with a westbound GO Transit train at the level crossing between Danforth Road and Midland Avenue just north of the Scarborough GO Train Station. Nine people were killed and 20 others injured. This was the worst accident in terms of loss of life in the history of both the TTC and GO Transit systems. The level crossing was replaced by an overpass a few years later. This also led to the Ontario-wide law that all public transit buses and school buses must come to a stop at level rail crossings prior to proceeding. On October 15, 1976, arson destroyed a train and caused significant damage to Christie station. Evidence remains today with the odd-coloured trim tiles on the top of the station walls at the centre of the platforms. A section of the line was closed for two days. On June 1, 1982, electrician Reynold Achong was killed by a train while working on the tracks at Summerhill station. On August 11, 1995, the Russell Hill subway accident resulted in the deaths of three passengers and injuries to 30 others. There were an additional 100 passengers who filed injury-related claims from the accident. In late 1995, TTC employee Jimmy Trajceski was killed during a robbery at Victoria Park station. Adrian Kinkead was arrested four months later for the crime and was found to be responsible for two other murders. He was convicted on all three counts and sentenced to life imprisonment. On September 27, 1997, 23-year-old Charlene Minkowski was killed when she was pushed in front of a southbound train at Dundas station. Herbert Cheong, a diagnosed schizophrenic, was convicted of second-degree murder and sentenced to life in prison with no possibility of parole for 15 years. In January 1999, an exceptionally large snowstorm paralyzed parts of central Ontario and the American Midwest. Over a two-week period, of snow fell, with falling in a single day. As a result, the city and the transit system were severely impacted. In the following days, major interruptions and delays were incurred and TTC policies to handle snow were changed.

2000s 2000–2009 On December 8, 2000, a garbage train caught fire while en route through Old Mill station. The train was completely destroyed and the station remained closed for two days. Since the incident, the TTC has stopped the practice of using garbage trains and maintains a fleet of surface garbage trucks to collect refuse. On August 14, 2003, the Northeast Blackout severely impacted TTC services. Without power, subway service was suspended and 18 trains were stuck in tunnels; however, all other trains were able to coast to the nearest station to be evacuated. Streetcars remained stationary where they were, and buses fought to get through gridlocked traffic, hampered by the lack of traffic signals. The subway did not reopen until August 18, the longest complete interruption in subway service in the history of the TTC. The incident led to an extensive review of TTC emergency procedures. On February 6, 2006, Mary Kim was born on a subway train at Wellesley station, the first such birth in the Toronto subway system. TTC officials later promised Mary Kim lifetime access to the TTC's service. In February 2006, four people were arrested for counterfeiting TTC tokens and smuggling them into Canada. The TTC lost an estimated $10million dollars in revenue. The suspected manufacturer in Massachusetts claimed to be unaware they were involved in a counterfeiting scheme. The fake tokens used the same aluminum alloy as genuine TTC tokens produced by the Royal Canadian Mint. In late 2006, the TTC introduced a new bi-metal token design to thwart counterfeiting, which was in use until tokens were completely discontinued in the 2020s in favour of Presto. On April 23, 2007, a TTC asbestos removal crew employee, Tony Almeida, was killed and several others were injured at the end of a night shift when the work car they were operating snagged on some cabling and dislodged a work platform. The TTC was fined $250,000 ($ in dollars) for violating the provincial Occupational Health and Safety Act. It was later found that Almeida was under the influence of cannabis.

2010–2019 On August 30, 2011, a woman was killed when a TTC bus rear-ended a flatbed truck carrying a crane on Lawrence Avenue between Victoria Park Avenue and Don Mills Road. At least 13 other people were injured in the crash. The bus driver was charged in the incident. On July 22, 2012, two people were injured when a bus crashed into a building on Queen Street West at Peter Street. The bus hit a car and then a taxicab before slamming into the building. On August 10, 2012, a man was chased through Lawrence East station and gunned down against a fence. He survived with critical injuries and was identified as one of the emerging leaders of the Galloway Boys street gang. On September 14, 2012, before the start of service TTC employee, Peter Pavlovski was killed and another TTC employee was seriously injured after being struck by a subway maintenance train north of Yorkdale station. The investigation prevented many trains from departing the Wilson Subway Yard, affecting morning rush service. On July 27, 2013, 18-year-old Sammy Yatim was shot dead by police aboard the 505 Dundas streetcar. The police officer who shot Yatim dead was later charged with second-degree murder and attempted murder and was found guilty of the latter. On August 13, 2013, a cube truck crashed head-on into an idle TTC bus near Middlefield Road and Steeles Avenue East. The accident killed one person and injured 12 people. Between December 21 and 22, 2013, a violent ice storm impacted TTC service. On December 22, all streetcar service was suspended for most of the day due to thick ice on the overhead wires. Between December 22 and 23, all of Line 3 Scarborough was shut down, and power issues led to Line 4 Sheppard being closed between December 22 and 24. A number of disruptions were also reported on Line 1 Yonge–University and Line 2 Bloor–Danforth, with some stations being closed for several hours due to power outages. On January 29, 2015, a brawl occurred at the concourse level of Union station just after a Toronto Maple Leafs game. Two intoxicated men were resisting arrest and fighting with transit special constables. During the arrest, two TTC Transit Enforcement Unit officers punched one man in the face several times and another man in the ribs during the arrest. Toronto Police arrived and charged the two men. A cell phone video was later posted on Facebook, causing public scrutiny and backlash against the TTC. An independent review of the incident later deemed the arrest and subsequent use of force to be lawful. Two years later, the victims filed a $4million lawsuit against the TTC and the two enforcement officers. On June 8, 2015, between 6:30a.m. and 8:00a.m., the entire subway network was shut down due to "major communication issues" between TTC subway trains and the TTC's transit control centre. Hundreds of thousands of commuters were stranded during the shutdown since no shuttle buses were provided to replace subway service. TTC officials believed the incident was caused by a defective switch that drained the battery for the backup power supply. On June 18, 2018, a man believed to be in his mid-50s to early 60s was pushed onto the eastbound Line 2 Bloor–Danforth tracks at Bloor–Yonge station and died when struck by an incoming subway train. A first-degree murder charge was laid against the man accused of the attack.

2020–present On June 12, 2020, there was a near-collision between two subway trains on Line 1 Yonge–University. Before the incident, train 123 was standing on the pocket track on the south side of Osgoode station while train 114 was holding northbound at St. Andrew station with a medical emergency on board. Both trains started to head north towards the switch connecting the pocket track to the northbound main track at Osgoode station. The guard at the rear of train 123 spotted train 114 moving and alerted the operator who stopped train 123 within of train 114. Train 123 with two crew aboard was running at , while train 114 with 5 passengers and 2 crew was running at . The mainline was under automatic train control (ATC) but Transit Control had instructed the crew of train 123 to use manual control on the pocket track. Train 123 was facing a red light on the pocket track, but it was not parked far enough in for its operator to properly see it. The TTC gave unpaid suspensions to the operators of train 123. The TTC union blamed a flaw in ATC that prevented its use on the pocket track. After the incident, the TTC disallowed manual mode on the pocket track. On October 29, 2021, the TTC became the target of a ransomware attack, which shut down Vision, the TTC's communications systems. After the attack, the TTC used its backup radio system to communicate with vehicle operators. Also affected were the TTC website (which had debuted its redesign to the public a few days prior), TTC internal email, Wheel-Trans online bookings and displays of next bus information. TTC staff detected unusual network activity on the evening of October 28, 2021, but the full effect of the attack peaked on the afternoon of October 29, 2021. By November 11, 2021, the TTC disclosed that the hackers may have had the ability to access personal employee information, such as social insurance numbers. As a result, the TTC offered three years of free credit monitoring and identity theft protection to its current and former employees. By this time, the TTC had restored its most important computer systems; however, its email system continued to remain offline. In December 2021, a vandal damaged elevators at 11 subway stations. Temporary repairs were completed within 24 hours, and TTC special constables apprehended a suspect, who was charged with ten counts of mischief. On January 17, 2022, a heavy snowfall of crippled public transit in Toronto, including the TTC's subway, streetcar and bus systems. The TTC reported that 540 of its 1,300 vehicles in service were disabled on the street, including buses, which normally do not use snow tires. Open sections of the subway system were not operational due to mechanical issues caused by heavy snow, with some sections closed until the end of service that day.