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The Bologna–Florence railway is one of the major links in the Italian rail network, connecting the railways of the Po Valley with the railways of Tuscany and central Italy under the Apennines. It is also known as the Bologna–Florence Direttissima—"direttissima" is Italian for "most direct". It was Italy's greatest engineering achievement in the first half of the twentieth century. When it opened in 1934 it significantly shortened the old winding Porrettana line over the Apennines via Pistoia, and was made possible by the 18.507 km-long Apennine Base Tunnel. The new Bologna–Florence high-speed railway was opened on 5 December 2009; it includes 73.8 km of tunnels in its 78.5 km length. ==History== |} The Porrettana line was opened across the Apennines between Bologna and Florence via Pistoia and Prato in November 1864 to connect the trunk railway of the Po Valley (the Milan–Bologna and the Bologna–Ancona railways, completed in 1861) with the railways of Tuscany. Florence was finally connected by rail with Rome via Perugia in 1866. The Porrettana line was immediately successful but while it was a significant engineering achievement it soon became clear that it was inadequate to cater for the traffic attempting to use it. In particular, it was a single track line, with steep gradients and its Apennine tunnel was built on a steep slope causing climbing steam trains to generate suffocating smoke, even when extra ventilation shafts and fans were eventually installed. Various projects for additional crossings of the Apennines were developed, and the Pontremolese line was opened in 1892 between La Spezia and Parma providing an alternative route from Rome to Milan. The Faentina line was opened in 1893 from Florence to Faenza as another alternative route. However these lines suffered from the same basic problem: they were mountain lines consisting of a single, winding track and were subject to being obstructed by snow in winter. As time passed, traffic increased, but so did technical expertise in drilling long tunnels, so it became possible to envisage more direct routes with reduced climbs up a pass. In 1882 the designer of Porrettana, Jean Louis Protche, was commissioned by several institutions to examine a number of projects including one dating back to 1871, proposed by the engineer Antonio Zannoni which proposed a more easterly route for the new line in order to reduce the length of climb. Protche chose a slightly different route through the valleys of the Setta and Bisenzio rivers, connecting with the existing line in Prato, and passing under the Apennines through an 18,032 m tunnel; its approach line would have had a total vertical climb of 328 m at a maximum slope of 12 per thousand. In 1902, the Colombo Commission was established to study the proposals of Protche and Zannoni along with those of several other engineers, Sugliano, De Gaetani, Naldoni and Mercanti. In 1908 the government authorised for a budget of 150 million lire dor final studies for the project and its construction. The approval of the final route of the ''Direttissima'', however, continued to debated until 1911. The project was then approved for a double track line using electric traction, widely spaced stations, 31 tunnels—which alone constitute 37% of the line—and numerous bridges. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Bologna–Florence railway」の詳細全文を読む スポンサード リンク
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