Three Canadian National trains carrying combustible and flammable materials were stopped near Armstrong, Ontario, shortly before 5 p.m. as wildfire flames surrounded one locomotive.
Crew video showed fire whipping against the windows and operators radioing for help, warning they were "encased in flames" before the train was eventually cleared to move.
Ontario Provincial Police said there was no immediate threat to public safety, while emergency responders and railway officials assessed conditions and maintained safety measures.
Ontario's fires are also driving a smoke plume across the Great Lakes and Northeast, with forecasts warning of reduced visibility and very unhealthy air where the thickest bands settle.