In the August issue of Continental Modeller there is a nice review of the video on the Braunlage - Andreasberger Eisenbahn:
The video is availabe in DVD and Blue Ray format and can be ordered here: https://www.jaffas-moba-shop.de/buecher/
While the BlueRay variety is still in good stock, of the DVDs there is only a single digit number left, and Jaffa is going to order another bunch soon. But if you hurry ....
Otto