During the steam era the Illinois Central's Paducah, KY, shops were masters at "kit bashing". Between 1937 and 1942 the shops constructed 4-8-2's 2500-2555 using 2-10-2 boilers mounted to new frames.
This meant there were now 56 surplus 2-10-2 frames. 41 of these frames were used to construct the 2100-class 2-8-2's, numbers 2100-2140 (the boilers for these locomotives came from 2-8-2's, which were surplus from other projects).
Between 1939 and 1941 the remaining 15 frames (minus the trailing truck) were mounted to old 2-8-2 boilers to construct 2-10-0's number 3610-3624. These rebuilds were definitely unorthodox, but several of these kitbashed 2-10-0's served into the mid-1950's.
3616 is seen inside the roundhouse at Paducah KY, on Dec. 30, 1959. The locomotive was created in December, 1939, by mating the boiler of 2-8-2 1566 to the frame of 2-10-2 2925. Meanwhile, 2925's boiler was used to construct 4-8-2 2533!
Don Morice photo