The derailment happened Sunday morning.
Police are on scene near Brunette Avenue and Columbia Street, where at least three cars ran off the tracks as the train approached the Fraser River Rail Bridge.
It's unclear what materials are inside the cars, but it appears they are not considered dangerous as no hazmat units have responded.
Police say the cars will be back on track and operations will resume within a couple of hours.
MAP: CN train derailment near Columbia Street and Brunette Avenue, New Westminster