1979 Mississauga train derailment

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Mississauga train derailment
Canadian Pacific freight train derailment, Mississauga, 1979.jpg
DateNovember 10, 1979
Time11:53 p.m.
Location Mississauga, Ontario
Coordinates 43°34′16″N79°38′24″W / 43.5710°N 79.6401°W / 43.5710; -79.6401 Coordinates: 43°34′16″N79°38′24″W / 43.5710°N 79.6401°W / 43.5710; -79.6401
Operator Canadian Pacific
Incident Type Derailment
Cause Overheated journal bearing

The Mississauga train derailment of 1979, also known as the Mississauga Miracle occurred on Saturday, November 10, 1979, in Mississauga, Ontario, Canada, when a 106-car Canadian Pacific freight train carrying chemicals and explosives including styrene, toluene, propane, caustic soda, and chlorine from Windsor, Ontario derailed near the intersection of Mavis Road and Dundas Street in Mississauga, Ontario. As a result of the derailment, more than 200,000 people were evacuated in what was the largest peacetime evacuation in North America until the New Orleans evacuation of 2005. There were no deaths resulting from the incident. This was the last major explosion in the Greater Toronto Area until the Sunrise Propane blast in 2008.

Mississauga City in Ontario, Canada

Mississauga is a city in the Canadian province of Ontario and a suburb of Toronto. It is situated on the shores of Lake Ontario in the Regional Municipality of Peel, bordering Toronto. With a population of 721,599 as of the 2016 census, Mississauga is the sixth-most populous municipality in Canada, third-most in Ontario, and second-most in the Greater Toronto Area. It is also one of the most populous suburbs in the world outside of Asia.

Styrene chemical compound

Styrene, also known as ethenylbenzene, vinylbenzene, and phenylethene, is an organic compound with the chemical formula C6H5CH=CH2. This derivative of benzene is a colorless oily liquid that evaporates easily and has a sweet smell, although high concentrations have a less pleasant odor. Styrene is the precursor to polystyrene and several copolymers. Approximately 25 million tonnes (55 billion pounds) of styrene were produced in 2010.

Toluene, also known as toluol, is an aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a CH3 group attached to a phenyl group. As such, its IUPAC systematic name is methylbenzene. Toluene is predominantly used as an industrial feedstock and a solvent.



On the 33rd car, heat began to build up in an improperly-lubricated journal bearing on one of the wheels, one of the few still in use at that time as most had long since been replaced with roller bearings, resulting in the condition known among train workers as a "hot box". Residents living beside the tracks reported smoke and sparks coming from the car, and those who were close to Mississauga thought the train was afire. The friction eventually burned through the axle and bearing, and as the train was passing the Burnhamthorpe Road level crossing, a wheelset (one axle and pair of wheels) fell off completely.

Hot box

A hot box is the term used when an axle bearing overheats on a piece of railway rolling stock. The term is derived from the journal-bearing trucks used before the mid-20th century. The axle bearings were housed in a box that used oil-soaked rags or cotton to reduce the friction of the axle against the truck frame. When the oil leaked or dried out, the bearings overheated, often starting a fire that could destroy the entire railroad car if not detected early enough.

Burnhamthorpe Road

Burnhamthorpe Road is a major arterial road in the cities of Toronto and Mississauga, Ontario; beginning at Dundas Street, near Islington Avenue, running west and becoming a rural road in the Town of Oakville, where it terminates at Tremaine Road, where it changes name.

Wheelset (rail transport) wheel-axle assembly of a railroad car

A wheelset is the wheel–axle assembly of a railroad car. The frame assembly beneath each end of a car, railcar or locomotive that holds the wheelsets is called the bogie. Most North American freight cars have two bogies with two or three wheelsets, depending on the type of car; short freight cars generally have no bogies but instead have two wheelsets.

Explosion and evacuation

At 11:53 p.m., at the Mavis Road crossing, the damaged bogie (undercarriage) left the track, causing the remaining parts of the train to derail. The impact caused several tank cars filled with propane to burst into flames.

Bogie wheeled wagon or trolley

A bogie is a chassis or framework that carries a wheelset, attached to a vehicle—a modular subassembly of wheels and axles. Bogies take various forms in various modes of transport. A bogie may remain normally attached or be quickly detachable ; it may contain a suspension within it, or be solid and in turn be suspended ; it may be mounted on a swivel, as traditionally on a railway carriage or locomotive, additionally jointed and sprung, or held in place by other means.

The derailment also ruptured several other tankers, spilling styrene, toluene, propane, caustic soda, and chlorine onto the tracks and into the air. A huge explosion resulted, sending a fireball 1,500 m (5,000 ft) into the sky which could be seen from 100 km (60 mi) away. As the flames were erupting, the train's brakeman, Larry Krupa, 27, at the suggestion of the engineer (also his father-in-law), [1] managed to close an air brake angle spigot at the west end of the undamaged 32nd car, allowing the engineer to release the air brakes between the locomotives and the derailed cars and move the front part of the train eastward along the tracks, away from danger. This prevented those cars from becoming involved in the fire, important as many of them also contained dangerous goods. Mr. Krupa was later recommended for the Order of Canada for his bravery, [2] which a later writer has described as "bordering on lunacy." [1]

Propane is a three-carbon alkane with the molecular formula C3H8. It is a gas at standard temperature and pressure, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel. Propane is one of a group of liquefied petroleum gases (LP gases). The others include butane, propylene, butadiene, butylene, isobutylene, and mixtures thereof.

Chlorine Chemical element with atomic number 17

Chlorine is a chemical element with symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity, behind only oxygen and fluorine.

Order of Canada order

The Order of Canada is a Canadian national order and the second highest honour for merit in the system of orders, decorations, and medals of Canada. It comes second only to membership in the Order of Merit, which is the personal gift of Canada's monarch.

After more explosions, firefighters concentrated on cooling cars, allowing the fire to burn itself out, but a ruptured chlorine tank became a cause for concern. With the possibility of a deadly cloud of chlorine gas spreading through suburban Mississauga, more than 200,000 people were evacuated. A number of residents (mostly the extreme west and north of Mississauga) allowed evacuees to stay with them until the crisis abated. Some of these people were later moved again as their hosts were also evacuated. The evacuation was managed by various officials including the mayor of Mississauga, Hazel McCallion, the Peel Regional Police and other governmental authorities. McCallion sprained her ankle early during the crisis, but continued to hobble to press conferences.

Hazel McCallion Canadian politician

Hazel McCallion, is a Canadian politician and businesswoman who served as the 5th mayor of Mississauga, Ontario, from 1978 until 2014. She is the first and current Chancellor of Sheridan College.

Peel Regional Police

The Peel Regional Police (PRP) provide policing services for Peel Region in Ontario, Canada. It is the second largest municipal police service in Ontario after the Toronto Police Service and third largest municipal force in Canada with 2,030 uniformed members and close to 844 support staff.

Sprain damage to one or more ligaments in a joint

A sprain, also known as a torn ligament, is damage to one or more ligaments in a joint, often caused by trauma or the joint being taken beyond its functional range of motion. The severity of sprain ranges from a minor injury which resolves in a few days to a major rupture of one or more ligaments requiring surgical fixation and a period of immobilization. Sprains can occur in any joint but are most common in the ankle and wrist.


Within a few days Mississauga was practically deserted, until the contamination had been cleared, the danger neutralized and residents were allowed to return to their homes. The city was finally reopened on the evening of November 16. The chlorine tank was emptied on November 19.

It was the largest peacetime evacuation in North American history until the evacuation of New Orleans due to Hurricane Katrina in 2005, and remains the second-largest as of 2016.

New Orleans Largest city in Louisiana

New Orleans is a consolidated city-parish located along the Mississippi River in the southeastern region of the U.S. state of Louisiana. With an estimated population of 393,292 in 2017, it is the most populous city in Louisiana. A major port, New Orleans is considered an economic and commercial hub for the broader Gulf Coast region of the United States.

Hurricane Katrina Category 5 Atlantic hurricane in 2005

Hurricane Katrina was an extremely destructive and deadly Category 5 hurricane that made landfall on Florida and Louisiana, particularly the city of New Orleans and the surrounding areas, in August 2005, causing catastrophic damage from central Florida to eastern Texas. Subsequent flooding, caused largely as a result of fatal engineering flaws in the flood protection system known as levees around the city of New Orleans, precipitated most of the loss of lives. The storm was the third major hurricane of the record-breaking 2005 Atlantic hurricane season, as well as the fourth-most intense Atlantic hurricane on record to make landfall in the United States, behind only the 1935 Labor Day hurricane, Hurricane Camille in 1969, and Hurricane Michael in 2018.

Due to the speed and efficiency with which it was conducted, many cities later studied and modelled their own emergency plans after Mississauga's.

As a result of the accident, rail regulators in both the U.S. and Canada required that any line used to carry hazardous materials into or through a populated area have hotbox detectors. [3]

Larry Krupa was inducted into the North America Railway Hall of Fame for his contribution to the railway industry. He was recognized in the "National" division of the "Railway Workers & Builders" category. [4]

The city of Mississauga sued CP in hopes of holding the railroad responsible for the massive emergency services bill. However, the city dropped its suit after CP dropped its longstanding opposition to passenger service on its trackage near Mississauga. This cleared the way for GO Transit to open the Milton line two years later. [5]

Hazel McCallion, in her first term as mayor at the time of the accident, was continuously re-elected ever since until her retirement in 2014 at age 93.

The song Trainwreck 1979 by Canadian band Death From Above 1979 is about the derailment:

It ran off the track, 11-79
While the immigrants slept, there wasn't much time
The mayor came calling and got 'em outta bed
They packed up their families and headed upwind
A poison cloud, a flaming sky, 200,000 people and no one died
And all before the pocket dial, yeah!

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  1. 1 2 Bibel, George (2012). Train Wreck: The Forensics of Rail Disasters. Baltimore, MD: Johns Hopkins University Press. pp. 171–2. ISBN   9781421405902 . Retrieved April 8, 2016.
  2. "Mississauga Train Derailment". Heritage Missisauga. November 10, 2009. Retrieved April 8, 2016.
  3. Bibel, 174
  4. The North America Railway Hall of Fame | Inductees: Larry Krupa
  5. "Riding the rails into Mississauga's past". Mississauga.com. Retrieved 13 January 2018.