CFD and Evacuation simulations for three railway tunnels

Although they are not common, and the latest standards make them highly improbable, the fires in trains can create critical situations due to the amount of people involved as passengers, remarkably if this situation happens inside a tunnel. Therefore, it is highly important to consider the necessity of installing mechanical ventilation in the railway tunnels, being this something that must be studied individually for each tunnel considering its specific characteristics.

Three railway tunnels were studied, with different characteristics in length, cross section and slope. For them, CFD and evacuation simulations were carried out with Pyrosim and Pathfinder, being coupled between them in order to obtain more accurate results in terms of evacuation time and poisoning. Visibility, temperature and FED were analysed to verify the tenability conditions during the evacuation.

The results showed that evacuation was feasible, but visibility was a matter of concern, and mitigation measures were needed. Finally, mechanical ventilation was judged as not necessary considering the evacuation conditions and the probability of this kind of incidents.