A number of derailed CN Rail cars carrying liquefied propane, plastic pellets and benzene continued to burn near the Saskatchewan-Manitoba border Monday.
More than 30 cars went off the track near Spy Hill, Sask., and burst into flames at 7 a.m. CT on Saturday.
The fire triggered the evacuation of 10 rural homes as the blazing tanker cars belched thick, black smoke into the air.
Fire crews have been working around the clock to try to quell the fire.
CN spokesman Kevin Franchuk said Monday that much of the benzene has burned off, but the propane cars were still burning.
Crews are also monitoring the cars of plastic pellets, which continue to smoulder, Franchuk said.
"The black smoke is nearly gone and the fire has been significantly reduced," he said.
A three-kilometre evacuation zone surrounding the derailment site remains in effect.
There have been no reported injuries.
Fred Odger said he and his family were at home inside the evacuation zone when the train derailed.
"It lit up the whole yard, house," Odger said, adding they all moved quickly to get away.
"We weren't long moving out because we didn't know what we were up against," he said.
He and his family spent the weekend staying with relatives.
CN said it has brought in its own air-quality monitoring team from the U.S.
Investigators with the Transportation Safety Board of Canada and provincial environment officials are at the scene and the cause of the derailment is still under investigation.
3 killed in 1972 crash
Nearly 40 years ago, in 1972, three people in Spy Hill were killed after a train hit a tanker right beside the tiny town of about 200 people.
"A girl from town was burnt fairly seriously at the time," recalled resident Morley Clark. "The explosion was bad enough that it took the paint off the buildings all along the street next to the rail line."
A temporary track being built around the derailment was expected to be complete by Monday.
Trains, including those of passenger line Via Rail, were expected to resume running on the modified line by evening.
A Via spokeswoman said about 150 passengers travelling across the country on the weekend were affected.
Passengers travelling west were flown from Winnipeg to Edmonton, and vice-versa for those coming to the east, said Catherine Kaloutsky.
"We detrained them in Winnipeg and Edmonton and flew them to the opposite point so they could then board the train for the remainder of their trip," Kaloutsky said.
She said Via's next cross-country departures from Toronto and Vancouver are slated for Tuesday, and the company expects the trains will be able to go right through.