The work and the technique: Bologna-Florence high-speed railway, Italy
The project represented a high-speed quadrupling of the Italian rail network and system.
Due to its size, technical and organizational difficulties, deployment of means and human resources as well as the orographic and hydrogeological characteristics of the Tuscan-Emilian Apennines to be crossed, the Bologna-Florence high-speed and high-capacity section was a major engineering challenge for our country and one of the most important projects in Europe.
The work, entrusted to a consortium led by Salini Impregilo then, now part of the current Webuild Group, began in 1996 and required the opening of 22 construction sites where a total of more than 2,000 people worked.
The works involved 79 km of sections, including 72 km of natural tunnels and 1.8 km of artificial tunnels, complemented by 6 viaducts-with lengths varying between 60 and 637 meters-in reinforced concrete or mixed (concrete-steel) and corresponding pile foundations. For the construction of the Bologna-Florence, a total of 9,920,000 m³ of material was excavated and 3,640,000 m³ of concrete and 30,000 tons of steel were used.
Among the tunnels, the most challenging were the Raticosa, the Firenzuola, and the Vaglia Tunnel. The latter, with a length of 18,713 meters, became upon completion the longest railway tunnel on Italian territory, surpassing the historic Apennine Tunnel (located on the Direttissima, the other railway line that directly connects Bologna and Florence), which held this record since way back in 1934.
However, the Vaglia tunnel is destined to lose the record to the main tunnel of the Terzo Valico dei Giovi, which is just over 27 km long. In the list of the longest tunnels in the world, the Vaglia tunnel occupies the 15th place.
Other works performed included the construction of a geological prospecting and service tunnel with a diameter of 5.50 meters and a length of 1,587 meters (excavated by the traditional method), the embankment of the railway body with earthworks including foundation soil remediation, the railway equipment and the electric traction, signaling, telephony, lighting, remote control and security and motive power systems.