How do fires affect the railway? - A Swedish study on what factors influence fire risk and how it affects railway traffic.

Abstract: Forest fires can start in a variety of ways. "Fires started deliberately" and "fires started by sparks generated from a train braking" were two of the most common causes of fires between 2010 and 2020. Train braking accounted for 1.1% of all fires, whereas fires created by unknown reasons accounted for 43% of all fires. The climate is expected to change in the future, and since different weather factors affect the risk of fire differently, it is interesting to observe how train traffic is currently affected by fires and where these fires occur, in order to prepare for and ease the consequences of future weather changes. In this thesis, the number of rescue missions reported was compared to two databases containing information concerning fires near the railway. They were compared because rescue operations imply that the fire was so broad at the time that aid was required, which makes it interesting to examine. Between 2010 and 2020, these comparisons produced 1,337 matches. Where matches represent how many times a fire was reported on one of these databases on the same day and location that a rescue mission was established. When delays were calculated, just one database was compared to the number of rescue missions, because the other one did not possess information about delays. This comparison produced 621 matches with a total delay of 203,821 minutes. The distribution of the counties where the matches and delays occurred was observed in order to determine which additional variables might have contributed. The population and land area were compared to the proportion of matches and delay minutes, and it was noticed that the counties of Stockholm, Västra-Götalands, and Skåne, which had the most people, were also in the top four for the most matches and the top eight for the most delay minutes. The municipalities with the largest values were also examined more closely, for both the 1,337 and 621 matches. For the 1,337 matches, the average temperature and average precipitation for the ten municipalities with the largest values in each category were compared to the average value for all 161 municipalities that were affected. For the 621 matches, the matches, the delay minutes and the number of affected trains for the ten municipalities with the largest values in each category were compared to the average value for all 130 municipalities that were affected. Regressions were used to calculate the impact of various weather events on the number of matches and the number of delay minutes. In the regression for the number of matches, temperature and precipitation were used as the independent variables which were taken from the 1,337 matches, these gave a result that both variables explain a portion of the matches. The regression performed for the number of delay minutes used the same independent variables but instead took them from the 621 matches, this showed that the variables did not explain the outcome of the number of delay minutes. Weather factors other than temperature and precipitation that have not been studied, such as relative humidity and wind speed, appear to have an impact on the number of matches, according to various sources. Where, for example, records on relative humidity from prior years correspond quite well with when a match occurs. Furthermore, the locations of matches and delays appear to be connected to the population, with more individuals implying a larger risk.