Eight cars of the train, which was carrying flammable liquids, came off the tracks as it was heading northbound out of Canadian Pacific Railway's Alyth Yard around 5 p.m. MT.
More than 140 people were forced to leave their southeast homes for four hours last night. Ninth Avenue had also been closed, but opened late Wednesday night.
"There were no leaks from any other cars, there were no injuries," said Ed Greenberg, a spokesperson for CP Rail.
Six of the cars overturned, two did not. A natural gas line was also ruptured during the incident.
Tankers were carrying a hydrocarbon
"The eight cars contained a diluent, a diluting agent, for pipelines, used also in the extraction and refining process of bitumen," said Greenberg.
The diluent is used to thin petroleum products, including bitumen from the oilsands, to help transport them through pipelines.
Fire department officials said the substance is a flammable and volatile hydrocarbon.
Crews worked Wednesday evening to empty the cars of their product so they could be uprighted.
"It's completely safe right now," said Brian McAsey, acting deputy chief of the Calgary Fire Department.
An investigation is underway to determine the cause of the derailment.
The Transportation Safety Board of Canada has also sent an investigator to look into the incident.
Residents 'frustrated,' says alderman
"Everyone's had a rough summer, between the flood and the noise issues at the Alyth shops," said Ald. Gian-Carlo Carra, who represents the neighbourhood where the derailment occured. "People are frustrated."
For many residents the experience is concerning because of how close it was to their homes.
"It is pretty concerning that it could happen again and that they're bringing these flammable liquids like, two blocks from our house," said Inglewood resident Jilleen Wallins. "But we're not moving, that's for sure. We love Inglewood."
Residents have long complained about noise and vibrations from the Alyth yard.
Complaints intensified in recent years after CP Rail consolidated train servicing work at the location, doubling the size of the operation that now runs longer hours.
This incident marks the third time CP Rail has had train derailment issues within Calgary in recent months.
In July, several cars carrying diluent derailed on the Bonnybrook rail bridge after it collapsed from underwater flood damage that went unnoticed by federal inspectors.
That incident sparked a debate over whether municipalities should have the authority to inspect railways crossing through city lines.
Railways are currently under federal jurisdiction and are not subject to municipal regulation.
As well, on September 10 a rail car slipped off the tracks at a crossing near the Alyth yard.
"I don't think we can rely on friendly relationships, I think we have to rely on rules and regulations that govern the important relationship that a city like Calgary has with an important national industry like the rail," Carra said.
"We have to have a really serious conversation about that."