Following the opening of KCR British Section in 1911, local authorities in Tai Po District Office proposed the construction of railway branch to boundary town Sha Tau Kok, which was likely to increase the revenue of mainline considering the stable movement of villagers between Sha Tau Kok Market and Sham Chun Market (now Shenzhen).

[2] The branch was built reusing the narrow gauge works railway tracks and rolling stock previously used to help construct the mainline.

[2] The line was opened to public in two phases, on 21 December 1911 from Fanling to Shek Chung Au,[3] and on 1 April 1912 to Sha Tau Kok.

[2] The branch facilitated the officials travelling to Sha Tau Kok, and benefited the villagers in the region, and merchants and workers frequently crossing the Hong Kong–China border.

The line was divided into four sections, between Fanling, Hung Leng, Wo Hing, Shek Chung Au, and Sha Tau Kok.

Foreseeing the inevitable closing of branch after the decision to build Sha Tau Kok Road in 1923, the KCR Corporation kept the expenditure as low as possible, but the number of passenger carried ironically rose to a record high.

From Au Ha to Sha Tau Kok the geography required that the line took its own less easy route, involving gradients as steep as 1:45 and curves of radius down to 150 feet (46 m).