Route A nice route would be the track from Niebüll where a lot of trains are loaded with cars to be carried over to Sylt. It would pass through the Station of Klanxbüll and pass over the Hindenburgdamm to the island Sylt. After reaching Sylt, there are two more small stops (Morsum and Keitum) before reaching it's final destination Westerland (Sylt). It's a nice scenic route through villages and fields and of course the 11km long dam passing from the mainland through the North sea to Sylt. The route in general is about 40 km long and it is not electrified which makes it quite a bit different from the other german routes. Train suggestions BR 245: The BR 245 is a modern dieselelectric locomotive biult by TRAXX and shares the same basic shapes with the BR 146, 185 etc. It's mainly running the cargo based operation on that route, meaning transporting the cars of the tourists over to the island and is currently entering Klanxbüll station BR 218: An older dieselelectric locomotive still running a lot on several lines but is mainly replaced by newer models like the BR 245 BR 928: The Syltshuttle is a small dieselcommuter stoping at all the small stations and brings over tourists who do not want to bring their car to the island or just want to go there for a one day adventure
The route could be expanded as well, if my proposal is a bit to short. There are options of continuing the line to the south or going up to the danish border. Also here are some more impressions
