BBC News (TV, The Travel Show) is running an episode on German trains this weekend.
https://www.bbc.co.uk/programmes/m001v91y
Emeline Nsingi Nkosi explores the German rail network. She heads into Berlin's underground U-Bahn system to visit the disused war bunkers built inside its stations, attends the opening of a museum dedicated to Wuppertal's distinctive suspended monorail, and rides a makeshift narrow-gauge train that links the remote Hallig Islands to the mainland.
also here: https://www.youtube.com/watch?v=JzgJ2D-4FgI