Sandiaoling is an area between Ruifang and Shuangxi Districts in New Taipei City, rich in tourism resources such as the Sandiaoling Historic Trail and the Sandiaoling Eco-Friendly Tunnel. Sandiaoling Station, opened in 1922, is the region’s key transportation hub. Located on the left bank of the Keelung River, it links Houtong to the north and Mudan to the south, and is the only Taiwan Railways station without a connecting road. Riding the train to Sandiaoling offers views of the magnificent upper Keelung River valley and its famous potholes. Set into the cliff face with no road access, this “secret” station—“with towering peaks before and behind, a fairyland in the Keelung River gorge”—was praised in Japanese-era guidebooks for its superb scenery. Nestled in the left-bank cliff, Sandiaoling is the sole Taiwan Railways station unreachable by road, drawing railfans and hikers alike. A third-class station served only by local trains, it is the junction of the Yilan and Pingxi lines, so visitors can see every type of east-coast train as well as Pingxi branch-line locals, watching trains burst from the tunnel in shifting light and split toward Jingtong or Yilan.