How electromagnets propel roller coasters to high speeds

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Muslim women working in a factory.

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Learn about mining and refining copper from the Atacama Desert, northern Chile.

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It was a world before streaming services.

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Both Union and Confederate forces needed trains to move and supply troops during the American Civil War, which meant that railroads determined the outcomes of some battles.

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Animation of the underfriction, or upstop, wheel, patented by American designer John Miller in 1919. It keeps the roller coaster on track, as does the guide, or side-friction, wheel, while the road, or running, wheel rides astride the track and carries the load.

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Abraham Lincoln once called the railroad the United States' most important goal.

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Learn about the technology used in Tokyo's railway system.