Change in thermal conditions during construction and operation of a long railway tunnel - takeing the Koralmtunnel as an example

Activity: Talk or presentationTalk at conference or symposiumScience to public


The requirements for the thermal conditions inside the tunnel differ between the construction phase and tunnel operation. During the construction phase, the main constraint is the maximum allowable air temperature in the working areas, since this must not be exceeded. In contrast, during railway operation, the thermal conditions in the tunnel itself are important because tunnel air is often used for cooling technical equipment, which is usually located in special rooms or zones within the cross-passages between the two tubes of th etunnel.

Thermal conditions in a tunnel depend on a variety of paramteres and these vary as one proceeds from the construction to the operation phase. To give a brief overview of the impact of such parameters, the Koralmtunnel, which is still under construction, is taken as an example. The Koralmtunnel (KAT) is an approximately 32.9 km long twin-tube railway tunnel located in the south of Austria, connecting the federal states of Carinthia and Styria. It forms, together with the Semmering base tunnel, the core part of the Austrian section of the Baltic-Adriatic axis within the Trans-European railway network. The KAT has about 70 cross-passages containing utility rooms for the electrical and IT equipment. To guarantee that the acceptable temperature limits for the single rooms are maintained, tunnel air is required for a cooling process. For reasons of cost efficiency, a simple mechanical ventilation system is to be installed in as many cross-passages as possible. Simulations were performed in order to identify those tunnel regions where tunnel air is cool enough to ensure compliance with thermal requirements.
Period12 Jun 2018
Event titleTunnel Safety and Ventilation
Event typeConference
LocationGraz, AustriaShow on map


  • tunnel climate
  • construction-operation requirements
  • thermal parameters