The Bavarian Class PtzL 3/4 engines with the Royal Bavarian State Railways (Königlich Bayerische Staats-Eisenbahnen) were rack railway locomotives whose cogwheel drive was designed for working on tracks with a Strub rack. In 1923 they were incorporated by the Deutsche Reichsbahn as DRG Class 97.1 (Baureihe 97.1) in their numbering plan. The locomotives remained on their regular route between Erlau and Wegscheid until the closure of this rack railway in 1963. The last journey was on 5 January 1963. They were scrapped in April 1964 at Simbach am Inn. (Wikipedia)