One of nine identical steam engines built in 1936 by Baldwin Locomotive Works in Eddystone, Pennsylvania, this locomotive was built originally as No. 304 for the Union Railroad to work the Pittsburgh steel mills. Sold to the Duluth, Missabe and Iron Range in 1949, it was renumbered No. 604 and used in Minnesota to push ore jennies onto the Duluth docks and drag empties up Proctor Hill. The engine was retired in 1958 and stored by the Bessemer in Greenville for future donation. Its 0-10-2 wheel arrangement was called a Union engine, and these were the largest steam switch engines ever built. At one time, there was a Franklin booster engine on the front truck of the tender. The engine had 61-inch drivers and developed 108,050 pounds of tractive effort. It was rated at 3,500 horsepower at 260 pounds of steam pressure. Engine and tender length was 87 feet, empty weight was 238 tons, loaded weight was 322 tons, and the tender carried 12,000 gallons of water and 14 tons of coal.