This 23.671 km long route was completed on 1 May 1900 under a Bavarian concession granted on 24 January 1897 to the Lokalbahn AG (LAG).

[1][page needed] On 1 January 1905 it was electrified, becoming the first railway in Germany to run on single-phase AC power.

But it was not until 1954/55 that the power system was converted to the usual 15 kV, 162/3 Hz by the Deutsche Bundesbahn, and four of the five DRG Class E 69 electric locomotives modified accordingly.

Pro Bahn demanded inter alia a new crossing place at Altenau (Bay) and the retention of the second track at Oberammergau.

For example, since the renovation in autumn 2005 there has only been one track at the terminus in Oberammergau; the rest of the area has been built on to provide a bus station and other facilities.

Furthermore, locomotives can no longer run around at the terminus in Oberammergau; only push-pull trains or multiple units can use the single track there.