The railway line linking the Tyrrhenian with the Adriatic coast of Italy will be doubled and made suitable for high speed train operation.
The part of the line currently running at grade between the stations of Terni and Spoleto will be flanked by an underground stretch of about 20 km.
The tunnel consists of two single track tubes. Only one of them will be, at the beginning, put in operation. The second will be excavated, but not yet equipped for railway service. It will, however, be equipped to serve as an escape way in case of an accident in the other tube. Later, when the train traffic increases, the second tube will be fitted out and put into operation.
The ventilation required in case of fire is based on jet fans, providing the longitudinal airflow needed to control the smoke propagation and to assure that the non-incident tube stays free from smoke during the evacuation phase.
The scope of the design was to define the minimum number of jet fans required to assure, in case of fire, the full control of the smoke propagation along the Terni-Spoleto tunnel.