Electro-Motive Division of GMC produced five different dual-purpose SDP models between August 1964 and June 1970: SDP45, SDP40, SDP38, SDP35 and SDP28. The entire SDP production was delivered to Class 1 mainline railroads, including those shipped to Korea.

Merger activity during the next two decades was strong and saw the names of SDP owners change. Names such as Atlantic Coast Line, Great Northern, Louisville & Nashville, National de Mexico/FNM, Seaboard Air Line gave way to new Class 1 operators, including Burlington Northern, Conrail, Seaboard System, and CSX plus regional railroads FerroMex and FXE. By that time most SDPs were getting long-in-the-tooth and faced retirement. Only a few of the dual-purpose SDPs found a place in the second-hand market, after retirement from mainline service, and it was not surprising, given the limited production. By 1990, most domestic EMD SDPs had been already converted to a SD40-2 or variant.

EL #3638 Photo Note: Some Erie-Lackawanna fans were quick to point-out the omission of EL's SD45Ms 3635-3653 from last month's part 1 profile. Although EL's elongated freight motors lacked a steam generator, they provided the requisite platform to hang a 5000-gallon fuel tank in place of a standard 4000-gallon. Thus, it is fitting to include them in this discusion given their multiple ownership (EL > Conrail > NS).

Sources:

• BN 1972 Motive Annual by F. Hol Wagner
• Extra 2200 South Locomotive Newsletter
• EMD Order Numbers at TrainWeb.com
• KCS 2011 roster by FL "Dutch" Schultz
• RRPicturesArchives.net
• William Davis, Jr.