Five families in West River Station have been told it will be at least five days before they're allowed back in their homes as the cleanup of the latest train derailment in Pictou County began Tuesday.​

Meanwhile, the company that owns the derailed train said it doesn't know what caused it to come off the tracks.

Denis Boucher, a spokesman for the owners of the Cape Breton and Central Nova Scotia Railway, said an investigation is underway into what caused several cars carrying a mix of propane and butane to derail on Monday.

The cars — two carrying butane and four carrying propane — remain strewn along the tracks on Lansdowne Road.

Gail Sinclair, who lives in one of five homes that were evacuated because they're within a five-kilometre radius of the derailment, said her life is on hold.

"My whole life is just disrupted. That's all. It's just not a normal day," she said. "Hasn't been a normal two days."

Sinclair and the other evacuees were allowed to return to their homes for two hours on Tuesday to retrieve some belongings. She said she's frustrated because she hasn't heard from the railway company.

"What if something explodes or whatever? It's scary. Apparently this stuff is odourless," she said.

"What if I was sitting in the house yesterday with all the windows open?"

No leaks detected, say fire officials

Officials say the cleanup will take several more days. Logs are being hauled in to prop up the tankers because the butane and propane inside can only be removed when the tanks are stable and level.

An access road needs to be built to accommodate the equipment and it takes eight hours to empty each tank.

Pictou County train derailment

The New Glasgow fire chief said his department's hazardous materials unit took readings at the scene on Monday and there were no leaks detected. (Anjuli Patil/CBC)

Terry Howe, an emergency response co-ordinator, said there's nothing to be worried about now.

"If everything is followed right, we don't have any issues," he said. "We've done it before and we've been doing it since 1998."

Const. Bryce Haight said there is minimal risk of fire, but police needed approval from the railway, provincial regulators and the remediation experts before allowing the families to return.

Police said the train's engineer realized there was a problem and stopped the train, which was en route to Truro from Stellarton.

New Glasgow fire Chief Doug Dort said his department's hazardous materials unit took readings at the scene on Monday and there were no leaks detected.

This is the second train derailment in two weeks in Pictou County. Three rail cars carrying sheets of steel derailed in the downtown area of New Glasgow on May 29. No one was injured.

With files from The Canadian Press