[openrailwaymap] Harzer Schmalspur Bahn

Dear OpenRailwayMappers, recently I had a look at the marvellous openrailwaymap. I am astonished by the many different classes for railway lines. Although commuting everyday by train, I never imagined so many different track types. One thing confused me, maybe you can enlighten me. Why is the 9701 "Brockenbahn" running to the top of the highest peak in the Harz mountains neither "Schmalspur" nor "Museumsbahn" but a "Überleitgleis". Even more confusing, at some stations the parallel tracks are tagged as "Schmalspurbahn" (e.g. Schierke). According to the website of the "Harzer Schmalspur Bahnen" http://www.hsb-wr.de/mehr-erfahren/streckennetz/interaktives-streckennetz/ the "Brockenbahn" and the "Harzquerbahn" are claimed to be "Schmalspurbahnen". thanks robert