The Transportation Safety Board of Canada says there will be a full investigation of the train derailment that spilled more than 63,000 litres of crude oil, after a CP freight train left the track and 22 cars derailed near White River.
Spokesperson Rob Johnston said some of the cars went down a rock-cut embankment that was nearly 30 metres high, making it difficult to inspect the cars that were stacked on top of each other.
Investigators are now looking at some damaged track and wheels.
"We're going to take a look at the fracture surfaces and we're going to evaluate the wheel," Johnston said.
"There's a portion of a wheel that is of interest. And we'll be doing some failure analysis back in the TSB laboratory in Ottawa."
Johnston says his crew should finish the on-site portion of their investigation — including interviews — by Saturday.
CP Rail has re-opened the rail line but cleanup operations continue at the site.
An environmental officer with the Ministry of the Environment is still at the site overseeing remediation.
"CP is currently in the process of clearing an access path, so they can get some vacuum trucks and additional material into the site," said Lisa Brygidyr, issues management coordinator for the ministry’s northern region.
"All of the spilled material remains contained. We're hopeful that the trucks will be able to access the site either later [Friday] or on the weekend."
She stated there is still no environmental impact to the river. The situation will be reassessed on Monday to see if the environmental officer will need to remain next week.