Alte Eisenbahn, Unfinished railway tunnel in Eggegebirge, Germany

The Alte Eisenbahn is an abandoned railway tunnel project in the Eggegebirge mountains between Lichtenau and Willebadessen featuring visible tunnel openings and water-filled excavations. The site displays multiple access shafts sunk into bedrock and deep cuts carved through the hillside during construction attempts.

Construction started in 1847 when the Cologne-Minden-Thuringian Railway Company began driving a 600-meter tunnel through the mountain. The work stopped early when funding dried up, leaving only one-third of the planned tunnel completed.

The name Alte Eisenbahn refers to the 1847 construction site of the Köln-Minden-Thüringer Verbindungs-Eisenbahn-Gesellschaft, which was left unfinished after the company's bankruptcy. The planned route would have run from Paderborn via Borchen, Atteln and Lichtenau to the tunnel, and on the east side via Borlinghausen and Bonenburg to Warburg. The public was told that permanent water inrushes ended the work.

The site lies in forest beside the L 763 between Willebadessen and Kleinenberg, with no parking area recorded in the sources. The 19 km Wilderer-Wanderweg loop passes directly by and gives views from above into both cuttings; the 70 km Eggeweg crosses the L 763 and allows a view of the eastern cutting. The cuts are 15 to 20 m deep and partly water-filled, so sturdy footwear is needed.

At the end of 2016, divers examined the flooded cuttings: these were the first underwater archaeological investigations by the LWL-Archäologie für Westfalen. The dive survey showed that only the Richtstollen (pilot tunnel) had been started and that the surviving west cutting was barely wide enough to carry rails.