Two investigators with the Transportation Safety Board are headed to Field, B.C., after multiple cars from a westbound train derailed on the CP line near the Upper Spiral Tunnels on Thursday.

The Transportation Safety Board (TSB) reported 27 cars had derailed on Thursday, but CP Rail on Friday clarified that 16 had derailed.

A count by TSB investigators ultimately determined 15 cars had left the tracks.

The derailment was reported on the CP Laggan subdivision, which runs from Calgary to Field, B.C., just after 10 a.m. MT. The train was travelling at 22 km/h. No injuries were reported.

The investigators "should be there very late tonight or early [Friday]," said TSB spokesman Alex Fournier.

The Upper Spiral Tunnels are near Cathedral Mountain, between Lake Louise, Alta., and Field, B.C.

CP said the train was carrying a variety of commodities and there were no concerns to public safely.

The Upper Spiral Tunnel lies between Lake Louise, Alta., and Field, B.C. (Google Maps)

It was the second derailment reported in a national park in two days.

CN officials said a gondola-style petroleum coke car came off the track on Wednesday near Jasper, Alta. There was no spill or leak reported and no injuries. The car remained upright and the track is being repaired.