The paper is devoted to modeling of nonstationary field of a passenger car wheel at braking. The calculation is based on formulation of thermal conductivity equation for the wheel tread as a curved rod with the application of linear approximation of thermal field. At formulation of thermal conductivity equation it is necessary to consider a balance of heat in small volume of tread with the consideration for thermal flow from braking shoe, thermal emission to the environment and thermal conductivity in circular direction. The authors have set for the initial equation of thermal conductivity a functional and have formulated conditions of stationarity that leads after integration to the system of the first order differential equations of time. The authors have applied the Euler method at integration. The developed method has been realized in the C++ program. With the use of this application the authors have conducted a research of the thermal field of the passenger car wheel. The method can be used at designing of new rolling stock and for the analysis of reasons of flaws appearance on the surface of car wheels.

The paper is devoted to optimization of maintenance and repair system of passenger cars. The method is based on the use of profitability as a criterion of optimization. Revenue from car operation is supposed to be uniform during a service life. Costs include price of construction, expanses on utilization (with deduction of income from the writeoff), expanses on repairs of large volume, expanses of other railway services and variable expanses on current maintenance of a car in inter-repair periods that are assumed to change linearly and quadratically during each inter-repair period. The authors propose a method to consider dependence of current repairs cost on a car condition during its life cycle. They also have developed a method of optimization of costs on roundhouse servicing and major overhaul. The proposed methods are realised on C++ language in the form of software package that can be used to control the passenger car repair system and for development of new cars.