A flatcar (also flat car) is a piece of railroad rolling stock that consists of an open, flat deck on four or six wheels or a pair of trucks (US) or bogies (UK). 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 containers or trailers in intermodal shipping.
Aircraft parts flatcarsAircraft 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).
Today, Boeing's 737 aircraft are shipped throughout the United States on special trains, including the fuselage.
Bulkhead flatcarsBulkhead flatcars are designed with sturdy end-walls (bulkheads) to prevent loads from shifting past the ends of the car. Loads typically carried are pipe, steel slabs, utility poles and lumber, though lumber is increasingly being hauled by centerbeam cars.
Centerbeam flatcarsCenterbeams are specialty cars designed for carrying bundled building supplies such as dimensional lumber, wallboard, and fence posts. They are essentially bulkhead flatcars that have been reinforced by a longitudinal I-beam, often in the form of a Vierendeel truss, sometimes reinforced by diagonal members. They must be loaded symmetrically, with half of the payload on one side of the centerbeam and half on the other to avoid tipping over.
Heavy capacity flatcarsHeavy capacity flatcars are cars designed to carry more than 100 tons (90.72 t) of lading. They often have more than the typical North American standard of four axles (one two axle truck at each end), and may have a depressed center or "fish belly" to handle excess-height loads as well as two trucks of three axles each (one at each end) or four trucks (two at each end) of two axles each, connected by span bolsters. Loads typically handled include electrical power equipment and large industrial production machinery.
Remote control useSome railroads, such as CSX, have former wood-carrying flatcars rebuilt into platforms which mount remote control equipment for use in operating locomotives. Such platforms are fitted with appropriate headlights, horns, and air brake appliances to operate in the leading position on a cut of cars (i.e. coupled ahead of the locomotive).
Intermodal freight useCOFC (container on flat car) cars are typically long and carry four 20 ft containers or two 40/45 ft containers (the 45 ft containers are carryable due to the fact that the car is actually long, using the strike plates). With the rise of intermodal cars, and given the age of most of these flats, numbers will decline over the next several years. Indeed, when the first double stacks appeared, many container flats were re-built as autoracks. The few "new build" container flats are identifiable by their lack of decking, welded steel frame, and standard 89 ft length. One variant is the car (which usually carries one large container as a load); these are actually re-built old boxcars. Common reporting marks are FEC, CP, SOO and KTTX. The ATTX cars, which feature no spark grips and sides, are built for hauling dangerous goods (ammunition, flammable fluids, etc.).
A TOFC (trailer on flat car, a.k.a. piggy-back) car once again, is usually an 89 ft car. In the past, these carried three trailers which are, as of 2007, almost obsolete, or one large, , or two 40 or 45 ft trailers. As intermodal traffic grows, these dedicated flats are in decline. Most have been modified to also carry containers. One notable type is Canadian Pacific Railway's XTRX service — dedicated 5-unit flats that only carry trailers.
Idler flatsIn marine service, the linkspan between a ferry or barge and its dock is very weak. In order to avoid loss of cargo and/or heavy locomotives, an old flatcar (which is usually the lightest car available) is used as a bridge between the locomotive on the dock and the cars on the ferry or barge.
Idler flat cars are also used in oversize freight service. Flatcars are flat, so if a gondola or large flatcar is carrying an oversized cargo, empty flatcars will be placed on both ends of the loaded car. This protects the cargo ends from damage and ensures that the loaded cars don't bind, and therefore damage, the ends of other cars.
Often a flat car is placed directly in front of a crane ("big hook") in order to:
- provide a way to remove a wrecked car from a crash site.
- provide a way to store new or removed rail from a work site.
- allow room for the crane's boom while in transit to and from a work site.
- Great Northern Equipment Color Pictorial: Book Two, Freight Cars
flatcar in German: Flachwagen
flatcar in Esperanto: Platforma vagono
flatcar in French: Wagon plat
flatcar in Japanese: 大物車
flatcar in Japanese: 長物車