This was a testbed for a proposed upgrade of all UP's SD24s, but UP decided not to go ahead with the work. Both UP 3100 and UP 414 were classified as "SD24m" by the UP, but some UP internal documents class UP 414 as a "SD24-4". CNW SD18R Several high-nose Southern SD24s were rebuilt by the Milwaukee Road and Morrison Knudsen for Precision National's lease fleet in 1979. The turbochargers and dynamic brakes were removed, and Precision gave them class SD10. In 1980 more followed, though they were low-nose units of Union Pacific origin. In 1982 the Chicago & North Western bought 22 of the high-nose and four of the low-nose units. Producing (without the turbocharger), they were designated model SD18R - not to be confused with actual SD18 locomotives as manufactured by General Motors Electro-Motive Division. Preservation At least two SD24s survive in museums: Chicago Burlington & Quincy 504, formerly Burlington Northern 6244 (which can be seen in the movie Groundhog Day), is preserved in operating condition at the Illinois Railway Museum. Wisconsin Central 2402, ex Fox River Valley Railroad 2402, built as Burlington 510, is at the National Railroad Museum in Green Bay, WI, mechanically complete except for traction motors, its currently being restored back to its Fox River Valley Railroad appearance. References External links EMD SD24 Diagram at the Illinois Railway Museum official website. SP SD24 info. C-C locomotives SD24 Diesel-electric locomotives of the United States Railway locomotives introduced in 1958 Locomotives with cabless variants Freight locomotives Standard gauge locomotives of the United States