Nehru Setu Bridge, spanning across the Sone River near Dehri-on-Sone in Bihar, is the longest railway bridge in India with a length of approximately 3.8 kilometers. This bridge was built in 1900 and remains an important rail connection on the Howrah-Delhi main line. The Narnarayan Setu is a road bridge, while the Jamuna Bridge and Thane Creek Bridge are not the longest railway bridges.