This diploma thesis deals with a valid legislation in the field of investigation of fire causes in the area of the Slovak Republic. In the individual chapters, there is described a fire protection in the selected rolling stock, its technical description elucidated as well as the locations with the higher risk of fire and dangers, which a fire investigator is threatened by at a seat of the fire. The fire statistics of the rolling stock for the period of 10 years (2009-2018) shows, how many fires arose in the Slovak area, the direct damage arisen, how many persons were injured and killed. The thesis examines three most common causes of the fire of a diesel locomotive, an electric locomotive and passenger cars. However, there are even more causes of the fire. The results of the fire statistics on the rolling stock follow that the fires of the diesel locomotives were the most frequent, there were the highest damages and the number of injuries was the highest. The research in the thesis is aimed at testing of covering materials such as (covering fabrics and leatherette) for railway passenger car seats. The research done by means of the three testing methods is focused on evaluation of flammability for the selected covering materials from abroad and Slovakia. We have found out that the composition of the materials is important, when the materials were made and used. During the first two testing methods the results were the same. The ignition of the materials was not realized. However, during the third method, there was an ignition of the old materials mostly. The best results were achieved with the newer covering materials, which are used nowadays. They are safer and in a higher quality than those used in the past.