The S50 is a railway service that runs every hour between Biasca and Malpensa Aeroporto Terminal 1 in the Swiss canton of Ticino and the Italian state of Lombardy, respectively. Treni Regionali Ticino Lombardia (TILO), a joint venture of Swiss Federal Railways and Trenord, operates the service.

Biasca railway station is a railway station in the Swiss canton of Ticino and municipality of Biasca. The station is on the original line of the Swiss Federal Railways Gotthard railway, at the foot of the southern ramp up to the Gotthard Tunnel.The line through the Gotthard Base Tunnel, now used by most trains on the Gotthard route, diverges from the existing line to the south of Biasca station, passing on the surface to the west of the town before entering the tunnel proper at Bodio. Biasca station can therefore only be served by trains on the slower, but much more scenic, original route.