In the steep valleys of Baishidu Town, the Yantang Bridge spans the Baisha River. Completed in March 1936, this eighty-meter-long concrete structure was a triumph of necessity. Facing severe funding shortages and a lack of imported steel, chief engineer Ling Hongxun chose to build with local stone and concrete. His team anchored the bridge's northern pier directly into an exposed natural rock outcrop on the canyon wall.

The bridge stands fifty meters above the rushing green water. It features a main arch spanning forty meters, which made it one of the largest concrete railway spans in pre-1949 China. Ling Hongxun carved his name and the year 1936 directly into the central face of the main arch. Today, visitors can still trace these deep intaglio letters with their fingers.

For over fifty years, steam and diesel locomotives roared across this narrow, six-meter-wide deck. The bridge deck lacks handrails. Concrete safety bays protrude from the sides every dozen meters. Here, track workers once pressed their bodies against the concrete, feeling the violent vibrations of passing trains while suspended over the canyon. During the Long March, the Red Army utilized this strategic corridor, leaving a legacy that later earned the bridge its status as a provincial revolutionary site.

The state decommissioned the line in 1988 after completing the Hengguang double-track project. Workers removed the steel rails, leaving a flat gravel and concrete roadbed. Today, the bridge is quiet. Local villagers walk across the empty deck to gather firewood, their footsteps echoing where heavy freight trains once rumbled. Across the river, modern trains on the new Jingguang line rush past, their noise drifting over to this silent monument of Chinese engineering.