Pictured is a model of a railway carriage introduced on the Stockton & Darlington Railway. How did we get from here to high-speed trains? 

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­Chugging across short distan­ces or entire continents, trains act as a major form of transportation worldwide. Also called railroads or railways, trains carry within their cars passeng­ers or freight -- such as raw materials, supplies or finished goods -- and sometimes both.

Back before the wild ideas of people like the Wright brothers, Henry Ford and Gottlieb Daimler, you had limited options for traveling around town and country. Paved roadways didn't always crisscross the countryside. Even with roads, horse-drawn vehicles still struggled to move people and goods, especially in bad weather. As early as 1550, pragmatic Germans constructed and used wooden railway systems, reasoning that horse-drawn wagons and carts could travel more easily and quickly over wooden rails than dirt roads. By the late 1700s, iron wheels and rails had one-upped wooden ones.

­But it wasn't until the steam locomotive was invented in 1797 in England that the railroad as we know it began to take shape. The Stockton & Darlington Railroad Company in England became the first public railroad to carry passengers and freight. Steam-powered locomotives carried six coal cars and up to 450 passengers a distance of 9 miles (14 kilometers) in less than an hour. Horses just couldn't top that.

Across the ocean, the B&O Railroad Company established itself as the first U.S. railroad company in 1827. By 1860, U.S. rail workers had laid more than 30,000 miles (48,280 kilometers) of track, more than in the entire world [source: AAR]. Railroads served as the main mode of transportation and made it cheap and easy to ship supplies and goods, even for Union and Confederate armies during the Civil War.

After the Civil War, the U.S. railroad network expanded again, and the country's first transcontinental railway was completed in 1869. Towns sprouted along the railway lines, and the railroad hastened westward expansion. By the early 20th century, U.S. railroads operated 254,000 miles (408,773 kilometers) of track. Diesel locomotives had replaced steam ones.

But by the mid-20th century, the decline of the U.S. railroads had begun. A developed interstate highway system and extensive federal regulations took their toll on trains. In the ongoing energy crisis, however, trains, which run on diesel and som­etimes even biodiesel fuel, may regain their former popularity with passengers as we move through­ the 21st century.

­Don't get derailed. Stick around as we talk about train technology, how trains move people and freight, and what the future of rail transportation may hold.