A company that operates a historic railroad that carries tourists through southwestern Colorado’s mountains and forests was accused Tuesday in a lawsuit of causing one of the largest wildfires in state history.

Federal investigators found that a coal-burning engine operated by the Durango & Silverton Narrow Gauge Railroad and American Heritage Railways threw cinders or other hot material onto brush near its track and started the 416 wildfire on June 1, 2018, according to the office of U.S. Attorney Jason Dunn.

Flames eventually consumed about 85 square miles of land near Durango, prompting evacuation orders affecting hundreds of people. Much of the damage occurred in the San Juan National Forest and on other federal land.

Crews declared the wildfire controlled in late July but it was not extinguished until late November. It was the sixth largest blaze ever recorded in Colorado.

Richard Waltz, an attorney representing the companies, declined comment on Tuesday.

Officials had not disclosed a cause of the fire before Dunn’s office filed the lawsuit, which says multiple eyewitnesses told federal investigators that one of the trains passed through the area immediately before the fire began.

The train is a recognized symbol of the tourism-centric region, carrying passengers in bright yellow cars between Durango and Silverton as steam rushes dramatically from the engine.

The company says in its advertising that the railroad has operated for more than 130 years under various owners and now carries riders on a 41-mile route.

Residents and businesses have filed their own lawsuit against the railroad company, arguing that it knew or should have known about drought conditions that summer.

A statement released by Dunn’s office said federal authorities estimated damage and fire suppression involving the blaze could hit $25 million.

“This fire caused significant damage, cost taxpayers millions of dollars, and put lives at risk,” Dunn said in a statement. “We owe it to taxpayers to bring this action on their behalf.”