Flatcar

A flatcar (US) (also flat car (US) or flat wagon (UIC)) is a piece of railroad (US) or railway (non-US) rolling stock that consists of an open, flat deck mounted on a pair of trucks (US) or bogies (UK), one at each end containing four or six wheels. Occasionally, flat cars designed to carry extra heavy or extra large loads are mounted on a pair (or rarely, more) of bogeys under each end . The deck of the car can be wood or steel, and the sides of the deck can include pockets for stakes or tie-down points to secure loads. Flatcars designed for carrying machinery have sliding chain assemblies recessed in the deck.

Flatcars are used for loads that are too large or cumbersome to load in enclosed cars such as boxcars. They are also often used to transport intermodal containers (shipping containers) or trailers as part of intermodal freight transport shipping.

Aircraft parts were hauled via conventional freight cars beginning in World War II. However, given the ever-increasing size of aircraft assemblies, the "Sky Box" method of shipping parts was developed in the late 1960s specifically to transport parts for the Boeing 747 and other "jumbo" jets of the time. The "Sky Box" consists of a two-piece metal shell that is placed atop a standard flatcar to support and protect wing and tail assemblies and fuselage sections in transit (originally, depressed-center or "fish belly" cars were utilized).

Boeing 737 aircraft have been shipped throughout the United States on special trains, including the fuselage.

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