Illinois Central Railroad No. 1 was a 4-6-4 "Hudson" type steam locomotive built in 1937 at the Illinois Central Railroad's shops from an older 2-8-4 "Berkshire" locomotive. It was designed to pull longer and faster freight trains, but the locomotive was unable to do so, since it was prone to wheel slippage. No. 1 was rebuilt to resolve the slippage issues, and it spent its final years in service pulling passenger trains.
In 1937, No. 1 was constructed at the Illinois Central Railroad's (IC) own Paducah, Kentucky shops from Illinois Central 7000 class 2-8-4 "Berkshire" No. 7038 as an experiment to haul fast freight trains. Freight traffic had been growing too large for the IC's 4-6-2 "Pacific" types, and they required more speed than the railroad's 2-8-2 locomotives could manage. The 2-8-4 class No. 1 was rebuilt from were prone to rough riding while traveling above 40 miles per hour (64 km/h).
The experiment was deemed unsuccessful. The No. 1 locomotive was prone to wheel slippage, since its factor of adhesion was too low—it was unable to obtain a proper grip on the rails. John L. McIntyre, the IC road foreman of locomotives at Clinton, Illinois where No. 1 was assigned during the 1938–1939 period, made some modifications to No. 1, including to the weight equalization across the locomotive's wheels and to reduce the cylinder diameter from 27 to 24 inches (686 to 610 mm).
The latter was to reduce the starting tractive effort to a level the locomotive's grip on the rails could handle. The improvements were successful, but the IC opted not to convert anymore locomotives to No. 1's specifications. The rest of the 7000 class 2-8-4s were rebuilt, but they retained their wheel arrangements, and the last were retired in the early-mid 1950s. In 1945, No. 1 was renumbered to 2499 and assigned to passenger service between Louisville and Fulton, Kentucky. It was retired from service in 1949, and it was dismantled for scrap shortly thereafter.
