In 1936, the civil engineer Ling Hongxun completed a monumental three-span concrete arch bridge over the Baisha River. This deep green waterway marks the rugged border between Hunan and Guangdong provinces. Known as the Provincial Boundary Bridge, the structure stands as a monument of Chinese engineering, built entirely by domestic hands during a period of intense national mobilization.

The bridge spans 105 meters in length, rising 26.03 meters above the river valley. Its central arch stretches 40 meters, flanked by two 20-meter side arches. To build it, workers mixed concrete in a remote mountain gorge, pouring the liquid stone into wooden molds. On the central arch wall, they carved the characters for "Provincial Boundary Bridge" alongside Ling Hongxun’s name and the date, Year 25 of the Republic of China. They also pressed stylized rice ear patterns into the wet cement, a visual nod to Guangzhou, the City of Rams.

During the War of Resistance Against Japanese Aggression, this bridge carried heavy steam locomotives transporting troops and supplies along the Yuehan Railway. In the winter of 1934, during the Long March, the surrounding Baishidu area served as a recruitment site for the Red Army, linking the bridge to the revolutionary struggle.

For over fifty years, the concrete arches vibrated with the rumble of passing trains. In 1988, the opening of the double-track Hengyang-Guangzhou Railway bypassed this single-track route. Workers removed the iron rails, leaving a flat, gravel-strewn roadbed.

Today, the bridge serves a quieter purpose. The old railway deck is a rural road where local pedestrians and small vehicles cross between the two provinces. Standing on the edge, visitors feel the dizzying height of the gorge. Directly adjacent, modern trains roar along the new Beijing-Guangzhou line, sending rushes of wind across the silent, yellowing concrete of the historic span. The old bridge remains a quiet observer, bridging two eras of Chinese transit.