The Taiping Mountain Forest Railway (Chinese: 太平山森林鐵路; Pe̍h-ōe-jī: Thài-pîng-soaⁿ Sim-lîm Thih-lō͘), also known as Bongbong Train (Chinese: 蹦蹦車; Pe̍h-ōe-jī: Póng-póng-chhia) is a 36.4 km (22.6 miles) long narrow-gauge forest railway with a gauge of 2 ft 6 in (762 mm) in Yilan County, Taiwan.

It runs at a height of 1.870 m to 1.950 m above sea level on the disused railway track and has thus only a relatively small gradient.

Thus, some of them have been repaired, some of them left as historic ruins, and others have had to be removed and replaced by modern suspension bridges.

[7] The Old Taiping Mountain Railway (Chinese: 舊太平山; Pe̍h-ōe-jī: Kū Thài-pîng-soaⁿ) has been removed and only very little information about it is available.

The New Taiping Mountain Railway (Chinese: 新太平山; Pe̍h-ōe-jī: Sin Thài-pîng-soaⁿ) is the main system that exists today.