Gemmenicher Tunnel (Vaalserquartier), Aachen Travel Guide

The Gemmenicher Tunnel, also known as Botzelaer Tunnel in Belgium, is an 870-meter-long railway tunnel located near Aachen, Germany, in the Vaalserquartier. This engineering marvel was constructed in 1872 by the Bergisch-Märkische Railway Company as part of the Aachen–Bleyberg–Welkenraedt railway line. The tunnel is named after the village of Gemmenich and is a significant landmark on the Montzen Route, connecting DB Strecke 2552 in Germany with SNCB Ligne 24 in Belgium.The tunnel is a unique border crossing, with approximately 250 meters of its length lying within Belgian territory. The border within the tunnel shifted slightly after Germany's territorial concessions following World War I. The tunnel passes under the Vaalserberg, the highest point in the Netherlands, at a maximum depth of 66 meters.Operationally, the tunnel has been managed by the German side since its construction, initially by the Bergisch-Märkische Railway Company, then by Deutsche Reichsbahn, Deutsche Bundesbahn, and since 1994 by Deutsche Bahn AG. Between 1989 and 1991, the tunnel was widened and renovated for future electrification. This included partially removing the up to 77 cm thick brickwork and replacing it with a reinforced 17 cm thick shotcrete shell. A third track was added in the form of a track intertwining towards the tunnel center, allowing trains with excessive loading gauges to use the route. The tunnel was electrified in 2008.Today, the Gemmenicher Tunnel stands as a testament to the region's industrial heritage and offers visitors a chance to explore its historical and ecological significance. Surrounded by greenery and hiking trails, it's a destination for both history enthusiasts and nature lovers.