Christopher Brimley updated June 6, 2011


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  • The First Turbo SD: Part 5

    by George Melvin

    ICG SD20 2015 is fresh from the shop in the striking gray-and-orange ICG livery of the era. In fact, the stacks are capped with black plastic. It was rebuilt from SOU SD24 6342 and was the fourth ex-SOU unit finished in the SD20 program. It has a look quite unlike an SD24 aside from keeping the proportions of the original unit. Decals: Microscale 87-409. Paducah, KY; September 1980.
    Model Railroading - April 2005 - Page 20

    (Editors Note: Oops. Due to my error, Part 6 was run last month, ahead of Part 5, which appears here. I dont think I can pass this mistake off as an April Fools joke though, so I apologize for any confusion my mistake may have caused our readers. Randy).

    The SD24 was produced in a period of transition in diesel development. They were some of the first second-generation units since they replaced earlier diesels rather than steam engines and as such were some of the first models, along with the GP20, designed for this purpose. They were also some of the first SD units built for longhaul mainline duty as the earlier SD7/9 lived up to their Special Duty moniker and were usually bought for certain service. These earlier SDs were often delivered concurrently with four-axle units bought for more general assignments. The SD was now graduating to mainline through freight assignments and as the decade of the 1980s began, sales of the SD40 and comparable models from General Electric were outnumbering those of four-axle road switchers.

    At this time, three of the four fleets of SD24s were finishing their careers with their original owners. Since Santa Fe had invested in a major rebuilding of their SD24 fleet, their units still had a number of years left to serve their original owner, but the other three roads were disposing of their SD24s. As we detailed in the installment covering the Burlington, 12 of their 16 units retired in 1982 were traded to GE for C30-7s, with the remaining four moving on to the Maryland Midland. The Union Pacific started retiring SD24s in 1977, but the Southern retired their entire fleet and sold them to Precision National (PNC) in January 1978. Of their 48 units, all but four went on to new operators.

    C&IM SD20 81 was originally SOU 6316 then ICG SD20 2022 before going to the C&IM in January 1996, 16 years after its rebuilding by ICG. It is one of five units, all ex-SOU units rebuilt in 1980 acquired by this coal-hauling shortline operating just 200 miles north of the home of the SD20s. This unit has ditchlights but no evidence of marker lights in the short hood. Note the location of the roads herald on the rear of unit 82. Springfield, IL; July 27, 2002. Decals: Microscale 87-595 and 87596 (stripes).
    Model Railroading - April 2005 - Page 21

    The Illinois Central Gulf (ICG) bought 18 units from PNC in 1979 and put them through their SD20 rebuild program right behind a group of 11 bought earlier from the Union Pacific. The ex-SOU units were rebuilt to SD20s 2012 through 2025 and units 2027, 2029, 2031 and 2033. Three more units were renumbered by PNC but were not rebuilt and were later sold to ICG and became SD20s 2035-2037. Prior to the acquisition of the former Southern units, ICG had begun acquiring SD24s from the Union Pacific. They started the SD20 program in 1979, and the first 12 units, numbered 2000-2011, were completed in late 1979 and early 1980. A year later, UP 448, the former demonstrator unit went to ICG and became SD20 number 2026.

    The first of what would become known as a Paducah Rebuild was done in 1967, the 50th year for the famous Illinois Central shop at Paducah, KY. This unit was an SW1 switcher, but the program was primarily to modernize the roads roster of first-generation Geeps. Between 1967 and 1982 over 1,000 units were rebuilt and most were given new model designations. The program expanded from rebuilding units from the IC roster to acquiring similar models from other sources and finally to the SD20 program which utilized several SD models never owned by the road prior to the rebuilding.

    To avoid confusion over the IC or ICG question, it should be noted that the original Illinois Central merged with the Gulf, Mobile & Ohio on August 10, 1972, to create the Illinois Central Gulf. Then, in 1988, the road once again became the Illinois Central and was merged with the Canadian National in 1999.

    Seven years later, we see IC SD20 2000 in the new solid black IC livery. The warning lights in the numberboard assembly have been removed but most details remain the same. This unit became Missouri & North Arkansas 1000 in 1994. Woodcrest, IL; July 1, 1990. Decals: Microscale 87-529.
    Model Railroading - April 2005 - Page 22 Model Railroading - April 2005 - Page 23

    The SD20 rebuilding was a thorough upgrading: the unit was stripped to the frame, the 567 engine was upgraded to a 645E rated at 2,000-hp, and the turbocharger was removed. A new sealed hood was added with a central air intake. A new cab was added and, in the case of former UP booster units, the unit received its first cab! Above the frame, the most visible evidence that the unit had been an early SD was the radiator and fan section retained from the donor unit. After rebuilding 38 units, 35 SD24s and three SD7s from the UP, the ICG went shopping for newer power and the last four of the total of 38 SD20s were rebuilt from ex Baltimore & Ohio SD35s, the model that replaced the SD24 in the EMD catalog.

    In the mid 1990s, the SD20 fleet started to break up, and several small to medium sized roads acquired these units. The Chicago & Illinois Midland, Indiana Harbor Belt, Iowa Interstate, Missouri & North Arkansas, and Wisconsin Southern have operated third-hand SD20s. A number of them were bought through dealer and lessor National Rail Equipment, which bought at least 16 of the fleet.

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