Vactrain

Train inside a vacuum tube

A vactrain is a proposed design for very-high-speed rail transportation. It is a maglev line using partly evacuated tubes or tunnels. Reduced air resistance could permit vactrains to travel at very high (hypersonic) speeds with relatively little power—up to 6,400–8,000 km/h (4,000–5,000 mph). This is 5–6 times the speed of sound in Earth's atmosphere at sea level.

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