In 1895 the intention was for a line that branched off the Freyung railway at Fischhaus and ran via Büchlberg and Hauzenberg to Wegscheid.

From now on railway passengers could enjoy the full splendour of the Danube to their left as they travelled through Löwmühle (formerly a halt) to Erlau.

The station at Erlau was only provided with one platform, which was not helpful for the subsequent crossing of trains from Wegscheid and Hauzenberg.

The Erlau–Obernzell railway ran picturesquely along the Danube until it swung away into the mountains towards Wegscheid at Obernzell (300 m above NN) over the viaduct (demolished in 1982).

From there it entered the rack railway section between 5.67 and 9.48 km from the start, running uphill to Untergriesbach (542,7m above NN), on through curves with radii as little as 200 m, and on inclines of up to 25 per mille on the adhesion section to Withterwasser (535,0 m ü. NN) in order to overcome the height difference.

For this railway, special steam locomotives were built, even during the planning and construction stages, by the firm of Krauss in Munich.

These were Class PtzL 3/4 locomotives, passenger tank engines with a rack railway system, three of the four axles being driven, with the works numbers 4101–4003, 8033.

The agricultural and forestry industries transport a large amount of produce by road and the line would also have been useful for tourism.