The paper substantiates an approach to assessing the fire hazard of spark discharges in the electrical equipment elements of passenger cars of rolling stock based on the detection of optical flashes using fiber-optic sensors. The presented numerical model makes it possible to realize the possibility of detecting and evaluating optical flashes of weak spark discharges on potentially fire-hazardous electrical contacts in the electrical networks of passenger cars. To solve this problem, it seems appropriate to place sensors of electrical discharges using optical fibers to deliver to them the radiation of optical flashes of spark discharges from fire-hazardous spatially remote elements of the electrical network.

Emergency states that arise at influence of free fire on an oil and gasoline tank shell lead to thermal stress that can cause shell damage, a decrease of hardness and material strength. The paper considers a method for determination of a non-steady thermal field of the shell in a fire centre. Besides, the authors have got a thermal conductivity equation in partial derivatives and suggest a new approximation of the thermal field in the form of polynomials. The method is realized in the MathCad program complex and can be used at design of railway tanks for transportation of dangerous freights and at development of systems for protection from emergency thermal influences.