In 1872 a railway line was proposed linking Menaggio to the town of Lugano and then onto Luino, on the eastern shore of Lake Maggiore. This proposal was soon reduced to construction of two separate lines linking Menaggio and Porlezza at the eastern end of Lake Lugano and Luino and Ponte Tresa at the western end of Lake Lugano. Ponte Tresa - Lugano - Porlezza traffic was to be serviced by steamboats along Lake Lugano. The change of plan was caused partly by difficulties in financing the proposal, particularly the substantial engineering works that would be required between Porlezza and Lugano, and partly over concern about opposition to the proposal from boat operators on the lake. The two railway lines were each just over 12 km in length.
Earthworks high above Menaggio not far from the tunnel c1884
On the 23 August 1873 government authorisation was given to form a company to build and operate the two railway lines. Although the railway lines were to be built on Italian territory, the company was based in Switzerland and finance provided by the Banca per la Svizzera Italiana [Bank for Italian Switzerland]. The Società di Navigazione e Ferrovie pel lago di Lugano (generally known by the acronym SNF) [the Navigation and Railways of Lake Lugano Company] was authorised to build narrow gauge railways between Menaggio and Porlezza and between Ponte Tresa and Luino and to operate them until 6 January 1973. Opposition to the plan delayed construction and it was not until June 1883 that contracts for the supply of materials and construction were awarded.
Construction of the viaduct over the Fontanin valley between Menaggio and Grandola c1884
The track was laid to the unusual gauge of 850mm. The rail weighed 27 kg per metre (~ 60 lb per yard) which had an expected lifespan of 60 to 70 years. The only tunnel on the Menaggio to Porlezza line, just east of Grandola, was 90 metres in length, 3.3 metres wide and had a height of 3.9 metres above track level. Bridges along the Menaggio to Porlezza line included a three arch brick and stone structure across the stream in the Fontanin valley, a stone bridge over the Menaggio to Porlezza road about 4.5 km from Menaggio and two iron bridges, one 24 metres long over the Cussio torrent and the other 10 metres long over the Rezzo torrent.
The intermediate station buildings at Grandola, Bene Lario, Carlazzo, S. Pietro di Sovera and Tavordo were similar in design having between 6 and 8 rooms, which included a ticket office, a baggage room, a small parcels office and lodgings for the stationmaster. The fašade to each building had a plaque showing the altitude of the station.
In March 1884 the first of the 6 locomotives ordered by the company arrived at Lugano and was transported by boat to Porlezza. Construction was nearing completion by June, but opening of the line was delayed by the late arrival of the final two locomotives and by an outbreak of cholera which caused the closure of the Italy-Switzerland border for a month. The Menaggio-Porlezza line opened on Wednesday 8 October 1884. The Ponte Tresa-Luino line opened on 26 February 1885.
Construction of the Menaggio - Porlezza line had cost 1.1 million Swiss Francs (1.2 million Italian Lire).