Melide is a railway station in the Swiss canton of Ticino and the municipality of Melide.
 The station is on the Swiss Federal Railways Gotthard railway, between Lugano and Chiasso.
 It is situated immediately to the west of the Melide causeway, which carries the railway, along with several roads, across Lake Lugano.
Taverne-Torricella is a railway station in the Swiss canton of Ticino.
 The station is located on the border between the municipalities of Torricella-Taverne, Lamone and Bedano.
 The station is on the Swiss Federal Railways Gotthard railway, between Bellinzona and Lugano.
Mendrisio railway station is a railway station in the Swiss canton of Ticino and municipality of Mendrisio.
 The station is on the Swiss Federal Railways Gotthard railway, between Lugano and Chiasso, and is also the junction for the Mendrisio–Stabio railway, currently only used for freight traffic, but being rebuilt as an international connection to Varese.
Mezzovico is a railway station in the Swiss canton of Ticino and municipality of Mezzovico-Vira.
 The station is on the Swiss Federal Railways Gotthard railway, between Bellinzona and Lugano.
Lugano (] ) is a city in southern Switzerland in the Italian-speaking canton of Ticino bordering Italy.
 It has a population (as of December 2016 ) of , and an urban agglomeration over 145,000.
 The 9th largest Swiss city, it is the largest in Ticino and largest with an Italian speaking majority outside Italy.
 The city lies on Lake Lugano, surrounded by the mountains of the Lugano Prealps.
Maroggia-Melano is a railway station in the Swiss canton of Ticino.
 The station is located on the border between the municipalities of Maroggia and Melano, and serves both.
 The station is on the Swiss Federal Railways Gotthard railway, between Lugano and Chiasso.
Giubiasco is a railway station in the Swiss canton of Ticino and municipality of Giubiasco.
 The station is on the Swiss Federal Railways Gotthard railway, between Bellinzona and Lugano, and is the junction point with the Luino–Bellinzona railway that has branches to Locarno and Luino.
Balerna is a railway station in the Swiss canton of Ticino and the municipality of Balerna.
 The station is on the Swiss Federal Railways Gotthard railway, between Lugano and Chiasso.
The Maroggia Tunnel is a railway tunnel in the Swiss canton of Ticino.
 The tunnel is situated on the eastern bank of Lake Lugano, between Bissone and Maroggia.
 It forms part of the Swiss Federal Railways Gotthard line, which links Lugano and the north of Switzerland with Chiasso and Italy, between the Melide causeway and Maroggia-Melano station.
 It is 569 m in length, and carries standard gauge () track electrified at 11 kV AC 16 2/3 Hz using overhead catenary.
Rivera-Bironico is a railway station in the Swiss canton of Ticino and municipality of Monteceneri.
 The station takes its name from the nearby villages of Rivera and Bironico, and is on the Swiss Federal Railways Gotthard railway, between Bellinzona and Lugano.
 Just to the north of the station, the line enters the Monte Ceneri Tunnel.

Question: Which Italian-speaking Swiss canton is served by the Swiss Federal Railways Gotthard railway in a city on Lake Lugano?
Answer: Ticino