The Alishan forest railway is one of only three high mountain railways existing in the world. Starting from a 30 meters altitude at Chiayi, the railway climbs through mountainous woodland to 2,216 meters high at Alisan. Owing to the special topography of Alishan, the locomotive at the early stage of the railway history was designed as 〝umbrella-like gear, vertical cylinder〞style and mainly used for transportation of timber. After a half-century's lumbering of the forest and the rapid development of tourism, the diesel train has superseded the steam train and turned out to be an alpine tourist train.