Spanish contractor Sacyr has begun work on a $267m railway bridge over the Biobío river in central Chile.

Due to be completed in 2025, the bridge will replace a viaduct built in 1889. That structure limits rail freight to a single track and is an impediment to the planned expansion of the country’s rail network around Concepción, known as the “Biotrén”.

The project involves building a 1.9km span to carry two tracks and a 320m tunnel. The aim is to allow trains to cross at up to 100km/h, and possibly also to accommodate double decker rolling stock.

According to local newspaper Diario Concepción, Sacyr has already built working platforms on either side of the Biobío, which is the second longest river in Chile.

Juan Antonio Carrasco, a regional president of EFE, the Chile’s State Railway Company, commented: “Until now, the railway bridge was a bottleneck that prevented us from thinking about a future expansion towards the province of Arauco or an increase in cargo transport.

“Now we are going to lift that restriction. The bridge will allow us to reach [the port of] Lota, avoiding urban centres. It will significantly increase the role of railways in our transportation system.”

Ricardo Montecinos, general manager EFE, added that before the pandemic, the Biotrén and the other main line, the Corto Laja, transported around 5 million passengers a year. This is expected to double in future, which he said would require more trains and larger stations.