Puente ferroviario de Ñuble, Railway bridge between Chillán and San Nicolás, Chile.

The Ñuble railway bridge is a 500-metre iron viaduct over the Ñuble River, painted yellow, with ten arches on each side and a third upper chord beam added between 1945 and 1947. Its reinforced concrete foundations support the metal structure on the boundary between Chillán and San Nicolás.

Built between 1885 and 1888 for Chile's Ministry of Public Works at a cost of about 450,000 pesos, the bridge was engineered by Enrique Budge with modifications by Domingo V. Santa María. Its 500-metre iron structure was fabricated in 1886 by Lever, Murphy & Co. of Caleta Abarca, Viña del Mar. Reinforced in 1924 with arches, counterweights and chains, it received its current third upper chord beam between 1945 and 1947.

The bridge marks the boundary between the communes of Chillán and San Nicolás, and between the provinces of Diguillín and Punilla; the river below gives its name to both the bridge and the Ñuble Region. It carries the trunk line of the EFE Red Sur between the Chillán and San Carlos stations, so passengers on long-distance services still cross it today.

The bridge is best viewed from the riverbanks or from nearby train stations where you can see its full structure clearly. Access from both sides of the river is straightforward, making it easy to photograph or observe the engineering details.

On 8 February 2006 a freight train derailed on the bridge, damaging three track sections over 150 metres. Long-distance services were replaced by buses between San Carlos and Chillán, and the repair cost $180 million, including replacement of more than 80 sleepers; passenger trains resumed on 7 March.