It's no doubt that railroads are an important part of distribution. One could argue many reasons for this with the main reasons including size of railroads, the low impact on the environment and cost and ease of operation.
With railroads in Canada such as CN Rail with approximately 15 000 route miles of main track including 750 in the States. And employees exceeding 21 000 that service all five of Canada's major ports: Halifax, Montreal, Thunder Bay, Prince Rupert, and Vancouver and strategic connections to the States through Chicago and Detroit, explaining why it is popular through its size. Another example of railroads power through size is shown when a single freight train can haul up to 200 trailers and containers at a single time.
Current highway delay, exceeds two billion hours annually in the United States, costing tens of billions of dollars per year in lost wages and wasted fuel. Building more highways is not the answer to this problem. Each new highway claims more scarce land, invites even more punishing traffic, and wastes additional fuel. It also increases air pollution, contributes to accidents, and exhausts publicly-funded road maintenance budgets. With its size, again a single freight train operating on privately owned tracks can carry up to 200 trailers and containers that otherwise would travel over public highways. By shifting freight form truck to rail highway congestion can be eased -- and so can pressure to build new highways.
Shifting freight from highways to rail saves fuel. One locomotive moves a ton of freight almost 300 miles on one gallon of fuel, while a truck moves a ton only about 100 miles per gallon. If just 10 percent of the freight moving by highway were diverted to rail, the nation could save 200 million gallons of fuel annually.
Tank cars have been in use on railroads since the late 1880's. Originally, they were made of wood and used to transport crude and refined oil products---even pickles in brine and oysters on ice---but their use has grown substantially. Today, tank cars are constructed of steel, stainless steel and aluminum and carry many of the chemicals, liquefied gases and foodstuffs used by industry and consumers to improve the quality of life. Railroads own very few tank cars. Tank cars usually are owned by leasing companies or shippers and marketers can have their own tank cars built, and railroads transport the cars in their direction. There are two general categories of tank cars--- those that carry their contents under pressure (pressurized cars) and those that carry their contents at normal atmospheric pressure (non-pressurized cars). Beyond these broad categories are a wide variety of designations that address the type, strength and thickness of material used for the tank.
Tank cars transporting higher hazard materials warrant the use of extra safety features. Among these are steel shields at each end of the car. These "head shields" are intended as further protection against puncture of a tank. To protect the tank in the event of fire, some cars may have thermal shields. Also, some cars have insulation (to maintain the product at constant temperature), bottom outlets, and/or pressure relief devices. The safety record of railroads moving hazardous materials is impressive. For every billion ton-miles of hazardous materials transportation, trucks ,which operate over inherently more dangerous public highways--are involved in five times as many accidents as are railroads. In 1991, railroads generated 65.9 billion hazardous cargo ton-miles on movements greater than 200 miles, and were involved in only 65 accidents or derailments involving a release of hazardous materials--fewer than one accident/derailment per billion ton-miles. Trucks, by comparison , produced 18.7 billion hazardous-cargo ton-miles on movements greater than 200 miles in 1991, but experienced 89 accidents in which an unintended releases of hazardous materials occurred, for a rate of 4.8 accidents per billion ton-miles.
For these reasons, such as size of railroads, the low impact on the environment and cost and ease of operation and many more reasons that can be stated, railroads are an integral part of distribution.