The failure of metal bar in a switch on the rail line was what caused a derailment on the White Pass and Yukon Route train in Alaska a week ago, says the company's president.
Nineteen people suffered minor injuries when two locomotives and four passenger cars went off the tracks near Fraser, on the American side of the Yukon-Alaska border, on July 23.
The vintage rail company hauls hundreds of thousands of tourists every year along the route of the historic Klondike Gold Rush from Skagway, Alaska, into Canada.
White Pass and Yukon Route president John Finlayson says the switch was unique and the only one used on the line.
He says it has been replaced and every other switch on the line has inspected and all are in good working order.
The cost of the accident has yet to be determined.
Train service out of Skagway was fully restored Saturday.