The Swedish Transport Administration is planning to expand the railroad network between Hallsberg and Stenkumla to increase the capacity and punctuality. The expansion includes a new track and also a new railroad tunnel.A fire on a passenger train located in a tunnel could lead to an evacuation scenario. Evacuation trough an underground tunnel during a fire is done with potentially great consequences. Several technical systems can be applied to minimize the consequences. One example of such technical system is a fire gas ventilation system which also is going to be the focus for this thesis. Regulations, interviews, comparisons, calculations and simulations have been used to answer the thesis objectives. • Which fire gas ventilation system is optimized for the railroad tunnel´s area of use? • How is fire gas ventilation systems performed in other railroad tunnels compared with the current tunnel? • What is the ongoing research work within the field about? • Can the research lead to new solutions of fire gas ventilation systems in the near future?After the identification of requirements, design parameters, system options and the indication by the calculations and simulations that risk reducing means might have to be applied. The application of a mechanical fire gas ventilation system was ruled out in the analysis due to other means are prioritized and more cost effective.The comparison with other railroad tunnels confirmed that the approach was similar due to the fact that the majority of Sweden’s railroad tunnels longer than 1 km without stations are not equipped with a mechanical fire gas ventilation system. Several limitations were discussed and they generated a continuous analysis consisting of profound information gathering and usage of more advanced simulation software. No major ongoing research about fire gas ventilation systems in railroad tunnels has been identified. / <p>Validerat; 20160630 (global_studentproject_submitter)</p>