The Biasca–Acquarossa railway (Italian: Ferrovia Biasca–Acquarossa; BA) was a Swiss metre gauge railway that linked the towns of Biasca and Acquarossa, in the canton of Ticino.
The Gotthard railway opened in 1882, providing a transport link to the communities of the valley of the Ticino River. In order to provide a link to the communities of the Valle di Blenio, the Biasca–Acquarossa railway was opened in 1911. The line closed in 1973 and was replaced by a bus service.
The line was 13.8 kilometres (8.6 mi) long, and was electrified at 1200 V DC using overhead lines. It commenced from the square in front of Biasca station, had 14 stops, a maximum gradient of 3.5% and a minimum radius of 133 metres (436 ft).
The main depot of the line in Biasca, which was built in the late 1960s, is in use as a bus depot by Autolinee Bleniesi, who operate bus services including those replacing the railway. The line's Acquarossa terminus is also used by the same company.