The investigation into the May 4 fire on the CP Rail Bridge over the Columbia River is ongoing.
A spokesperson for the Transportation Safety Board of Canada said it is up to CP Rail and the local fire department to determine the cause.
Rob Girard, the Revelstoke fire chief, said the department was not taking part in the investigation because it was on CP Rail land. A spokesperson for CP Rail said the fire was still being investigated.
The Transportation Safety Board would only investigate if CP Rail concluded the fire was caused by a train.
"If it's determined it's caused by railway rolling cause it would become reportable to us," said Peter Hickli.
CP Rail is expected to provide the TSB with a report on the cause of the fire once it is completed, after which the TSB could conduct its own investigation.