The primary purchaser of the U36B was the
Seaboard Coast Line Railroad, which ordered 108 locomotives. The
Auto-Train Corporation, whose
Auto Train ran primarily over the Seaboard, ordered another 17, for a total production run of 125. Four of these would be delivered to
Conrail after Auto-Train ran into financial difficulties. The Conrail U36B locomotives were fitted with AAR Type B trucks. The unit price was $285,000. GE manufactured the U36B between January 1969 and December 1974, during a period when railroads in the United States moved away from high-horsepower designs. There were multiple reasons for this change: rising fuel prices because of the
1973 oil crisis, higher locomotive maintenance costs, and poor
wheel adhesion, resulting from the primitive state of wheel-slip control at the time. With its per axle, the U36B was the "ultimate in adhesion-limited locomotives." GE would not market another such type until the
Dash 7 series in the late 1970s. Seaboard Coast Line #1776(2nd) (locomotive originally built as SCL #1813, it traded numbers with original #1776, which had already been released into service wearing the standard SCL Black with Yellow stripe paint scheme--1776(1st) became 1813(2nd and 1813(1st) became 1776(2nd)) was painted in a red-white-and-blue color scheme to honor the
United States Bicentennial and made numerous special trips.
Amtrak leased car six of Auto-Train's locomotives during the
unusually harsh winter of 1976–1977 to provide power for the
Chicago–
Florida Floridian. == Preservation ==