The Canadian Pacific S3 Diesel-Electric Locomotive No. 6591 was built in 1957. It was used as a switcher in the Smiths Falls area, moving short trains to nearby terminals as well as assembling cars to make up trains in the CPR smiths Falls yards. Historically, 6591 is believed to be the last engine to go through the Brockville Tunnel.
Diesel Electric Locomotive (6591) Built by Montreal Locomotive Works for CPR in 1957, this Diesel has only 600 hp compared to the 4,400 hp that locomotives have today. It was assigned to Smiths Falls and used in the freight yard, and was retired in 1982. In 1985, it was donated to RMEO and was then repainted. It is believed to be the last locomotive ever through the Brockville tunnel.