The Transportation Safety Board is warning that there is an increased risk of wheel failures on rail cars in the winter months.

A board investigation into the December 2011 derailment of a CN freight train near Cariboo, B.C., found a broken wheel was to blame.

In a report released today, the board says 19 cars loaded with coal rolled over.

A similar train derailment occurred along the same line near Fort Fraser, B.C., in February of 2011.

The board issued a safety advisory at that time, warning that Transport Canada has no regulatory requirements for a wayside inspection system and should review inspection criteria.

The board is reiterating the call for a better system for measuring wheel fatigue.