The class O-9 refers to one of various Canadian National 0-6-0 switchers. A total of 93 of these were originally built for the Grand Trunk Railway and were known there as class F. The Detroit and Toledo Shore Line Railroad only received two identical locomotives. The total of 95 locomotives were manufactured by the Grand Trunk's own workshops and by five commercial manufacturers. The service live of some ended in the thirties, but others survived until the fifties. The number 7312 is today owned by the Strasburg Railroad and is expected to be operational again by the end of 2023.