The first Mikados ordered by the Illinois Central from Lima was the class 1701. Lima manufactured part in 1915 and 1916, with the remainder being supplied by Lima and Baldwin in 1918 and 1919. They were largely similar to the class 1501 and 1551 locomotives.
In 1931, the firebox of number 1742 was modified. It received two thermic siphons and a brick arch. This increased the overall efficiency of the boiler by 8.47 percent, so that at least 50 other machines were rebuilt in the same form in the following years.