The RCMP say a vehicle on the highway suffered some minor damage from flying debris but no one was hurt.
Sgt. Steve LeClair says three empty cars of a northbound CN Rail train went off the tracks about 10 kilometres south of Pemberton, with one falling from the railway overpass onto the highway.
The road was closed in both directions for a while before being opened to single lane, alternating traffic — a situation that will remain until the derailed cars can be removed.
The cause of the derailment is under investigation.