The Interessengemeinschaft 3-Seenbahn e.V. is a German heritage railway located in Schluchsee-Seebrugg in Black Forest. It was founded on 13 January 2008 to prevent the demolition of the former freight yard in Seebrugg. At certain dates all over the year the volunteers organize and operate vintage train rides on the Three Lakes Railway (Titisee - Seebrugg) and on the Höllentalbahn (Freiburg - Titisee - Donaueschingen)
In 2008, Deutsche Bahn (DB) planned to demolish the abandoned former Seebrugg freight yard. At this time, the station was largely in the state of the 1950s, so eight railway enthusiasts founded a society to save the tracks from being removed. After they managed to stop the demolition and to buy the terrain from DB, they organized first steam train rides in August 2008, which were financed by ten communities near Seebrugg. They started to free the tracks from vegetation. Since 2009, the tracks are passable again. The same year in summer they were first used by steam trains.
In 2010 an original Baden water crane was placed in Seebrugg. In April a Henschel DEL 110, a 1939 Diesel-Electric switcher, was handed over by Club 41 073 as permanent loan. In May an Eilzugwagen reached Seebrugg as their first own rail vehicle.
In 2011 the society started to raise money to renovate the old tracks, which were about 50 years old and in poor condition. The districts of Lörrach, Waldshut and Breisgau-Hochschwarzwald and several communities in Black Forest promised financial support. Additionally, €270,000 were asked from the LEADER funding program of the EU. From 14 September until November 2014 the tracks were completely changed by Geiger + Schüle Bau Ulm. In the following years the overhead wiring will be hung up again after being illegally removed by DB in 2008.