C.P Rail says the train that derailed near Guernsey last Thursday, that leaked crude oil and and burst into flames, was using new tankers meant to be more puncture-proof than those in the Lac Megantic disaster.
The Transportation Safety Board is conducting the investigation, but has not yet released an estimate of the amount of oil spilled.
Nobody was injured, and there was no impact to waterways.
85 people living in Guernsey were evacuated as a precaution.