spoorbogen

Sp oorbogen is a Dutch term used in railway engineering to refer to the curved section of a railway alignment that connects straight track portions. The word combines spoor (rail or track) and boog (arc or bend). In practice, a spoorboog forms the horizontal curve of the line and is designed to guide trains smoothly from one straight run to another.

Geometrically, a spoorboog is defined by its radius and central angle and may be a simple circular arc or part of a more complex alignment that includes transition curves. A transition, or easement spiral, is often used to gradually introduce curvature from a straight section to the main curve, improving ride quality and reducing dynamic effects on rails, wheels, and ballast. The curve’s length, radius, and degree of curvature influence lateral acceleration and, consequently, the speeds that can be safely accommodated through the segment.

Design considerations for spoorbogen include speed targets, clearance constraints, and cant (superelevation) to counteract centrifugal forces at velocity. Engineers select radii appropriate to the planned traffic and enforce maintenance and monitoring of the geometry to preserve safe and comfortable operation. In practice, spoorbogen are a fundamental element of horizontal alignment planning and are routinely checked with track-geometry measurements.

The term is primarily used in Dutch-speaking contexts; in English-language railway terminology, the corresponding concept is typically described as a railway curve or track curve.