the locomotive that became 2124 was originally built as reading company class i-10sa 2-8-0 number 2044 in 1924. starting in 1945, reading began building a new class of 4-8-4 northern-type locomotives using the boilers and fireboxes from the i-10sas, designating these new locomotive the t-1 class. 2044 underwent this rebuild in late 1946 and emerged in january 1947 as the number 2124.