Carl's Railway is a disused railway line along the Diemel river between Hümme and Bad Karlshafen, which was opened on 30 March 1848 and finally closed on 27 September 1986. It was built as part of the northern section of the Frederick William Northern Railway; the rest of the northern section is now part of the Kassel–Warburg line.
The 16.5 km-long single-track line was the only line in the Electorate of Hesse connecting to a port on the Weser. At that time the Fulda river had not yet been channelised and river boats could not reach Kassel. The Carl's Railway together with the Grebenstein–Hümme section of the Northern Railway was the first railway in Kurhessen and it was one of the oldest railways in Germany.
Wikipedia https://en.wikipedia.org/wiki/Carl's_Railway
Address 34369, Germany
Coordinates 51°33'0.464" N 9°24'19.437" E