The incident took place around 4:30 yesterday afternoon in the area of Inglis Road.
The OPP say the fire broke out in the trailer unit.
The driver of the transport was able to stop on the side of the road and separate the trailer from his rig.
Fire crews were able to extinguish the blaze and the trailer was moved into the ditch.
Police say no-one was injured and no charges will be laid in connection to the incident.