The Warburg–Sarnau railway is a 100.9 kilometre-long, single-track, partially disused secondary railway line in North Rhine-Westphalia and North Hesse. The middle section, Korbach–Frankenberg, is called the Untere Edertalbahn or the Nationalparkbahn and the southern section, Frankenberg–Sarnau(–Marburg), is called the Burgwaldbahn.