Overview of Heritage Lines in Germany

There is a list in Wikipedia, which is incomplete and sometimes outdated: https://de.wikipedia.org/wiki/Liste_von_Museumsbahnen

Nils started to create a map of the heritage lines and groups in germany, currently Bavaria and Baden-Württemberg are close to finished: https://umap.openstreetmap.de/de/map/museumsbahnen_38011#6/50.785/10.239

Google Maps from eisenbahnplaner.net: https://www.google.com/maps/d/viewer?ie=UTF8&hl=de&msa=0&ll=50.736455%2C10.766601999999995&spn=9.740098%2C35.15625&z=5&source=embed&mid=131Q4rRc6jHuF6HOa9WqGF5X7jtY