The "tightness" of a train's turn is measured by its Minimum Curve Radius, and it varies drastically depending on the type of rail system. Standard long-distance freight and passenger trains are quite limited; they typically require a radius of at least 200 to 400 meters (650–1,300 feet) to navigate a turn safely at moderate speeds. If the turn is too tight, the rigid wheelsets of the train could climb the rail, leading to a derailment. However, light rail and streetcars (trams) are designed for urban environments and can turn much more sharply, with some systems managing a radius as small as 11 to 25 meters (36–82 feet). To achieve these tight turns, light rail vehicles often use "articulated" joints that allow the body of the car to bend. On high-speed rail lines (like the Shinkansen), curves must be incredibly gradual—often requiring a radius of 4,000 meters (2.5 miles) or more—to maintain speeds of 300 km/h without subjecting passengers to extreme centrifugal forces. In 2026, engineers also use "canting" (tilting the track inward) to allow trains to take curves slightly faster and tighter than they could on flat ground, but the physical length of the train cars remains the ultimate limiting factor in how sharp a turn can be.