Freight can be handled more economically in the United States and Canada than in most other countries because a high proportion of freight is moved in large units for long distances and can therefore be carried in long cars, which have a large capacity. The greater the capacity, the greater the ratio of the payload to the deadweight of the car. For example, a 14.6-m (48-ft) coal car weighing 27 metric tons can carry 77 tons of coal, but a 15.2-m (50-ft) car of similar construction, with a weight of 34 tons (23 percent more), can carry 109 tons of coal.
In a newly released report, the Federal Railroad Administration (FRA) finds that double stack freight rail transportation is up to five times more efficient than motor carrier transportation. The FRA's "Comparative Evaluation of Rail and Truck Fuel Efficiency on Competitive Corridors" underscores the advantages of projects such as the National Gateway. The National Gateway is a public-private partnership seeking to create a state-of-the-art, double-stack cleared rail corridor between East Coast sea ports and Midwest distribution centers. According to the FRA report, double-stack trains tend to be more fuel efficient than other types of trains. The study also cites increased efficiency, technology improvements and improved railcar designs.
Freight service is generally of two types. One type carries bulk commodities, such as coal, grain, or ore, and generally runs from origin to destination without switching, but on no set schedule. The other type of freight service operates on a regular schedule on a set route and carries all types of commodities. Most railroads operate trains containing only piggyback (trailer-on-flatcar) equipment on schedules almost as fast as passenger trains.
Freight trains transport goods such as coal, grains, ore, livestock, liquids, food, and other general merchandise. Large, sealed shipping containers are a common method of packing goods. During transport they ride piggyback on a type of freight car called a flatcar. The aforementioned 77-ton and 109-ton coal cars are among the largest freight cars in general use. A 36- or 45-ton boxcar offers a striking contrast to the freight cars of the early 20th century, when the usual capacity was 9 or 14 tons.
In the United Kingdom, where most freight is moved in small consignments on short hauls, most freight cars carry less than 14 tons. Most continental European freight cars are mounted on fixed wheels rather than on swiveling trucks and would be considered small or at best medium sized in the United States. Large cars similar in most respects to American cars are used to a considerable extent, however, in Russia and the other countries that were part of the former Union of Soviet Socialist Republics (USSR), and also in India and Australia and throughout Africa and South America.
A variety of rail freight cars is visible in this rail yard in Allentown, Pennsylvania. The black tanker car in the middle of the image carries oil or other petroleum products. The white hopper car is used for hauling bulk products such as grain or gravel. The brown and red boxcars are mulitpurpose cars that can carry a wide range of products or materials.
Besides boxcars, flatcars, and the open hopper or dump cars used for coal and ore, a variety of specially designed freight cars is made for particular purposes. Large semitrailers are carried piggyback on flatcars 24 m (80 ft) long. Refrigerated cars and, in freezing weather, heated cars, are needed for meat and other perishables. Special cars are provided for live poultry and livestock. Gases such as ammonia; liquids such as gasoline, oil, alcohol, acids, and paints; and also semiliquid or even solid products, including pickles, are often shipped in tank cars. The caboose, the small car that forms the tail end of a freight train, provides shelter and conveniences for the train crew. To permit the conductor to survey the entire train at intervals, the caboose usually has a glassed-in cupola projecting from the roof, but some cabooses have bay windows instead.
Beginning in the 1960s railroads began allowing higher freight-train speeds up to 112 km/h (70 mph) on some heavily used routes, although 80 km/h (50 mph) is more common. By the early 1980s, however, the industry had discovered that transit time could be shortened more easily by reducing the time that cars spent in yards than by raising speed limits en route.