The dissertation is devoted to the problem of improving the efficiency of the system of maintenance and repair of freight wagons, by moving from the operating system of planned repairs to the repair system in a condition that allows taking into account the real need for repair of freight cars. The expediency of an additional assessment of the technical condition of the units and parts of the vehicle by means of diagnostic means is considered.
The criteria for assessing the technical condition of freight wagons in operation and during repair is substantiated.
The current direction of evaluation of the technical condition is indicative control. Various performance wear and tear indicators are used in such crucial parts as friction wedge, adapter, slider, wheel, brake pad. The use of indicators minimizes the human factor in determining the wear units and parts of the wagon, shortening the time of technical maintenance of cars at the maintenance park, allows you to get around the car inspectors without the use of measuring instruments and templates.
The probability of finding a freight wagon in the corresponding life cycle will be determined by its previous technical condition, and the total magnitude of the set of all possible states consists of a Markov chain for random processes with random states and a continuous flow of time.
As a result of theoretical studies, the dependence of the probability of finding a freight wagon in working condition during the life cycle was obtained. On the basis of the obtained expression for the probability of finding a freight wagon in working condition, the expression for the coefficient of technical readiness of the car park is specified. Since the technical condition of the freight wagon is constantly changing, that is, maintenance or repair will be necessary, then this state can be divided into several levels, which will include: the level of maintenance required; the level of the need for ongoing repair; the level of the need for major repairs. For the proposed levels, the expressions for the probability of failure-free operation of the freight wagon in general form are taken, which takes into account the probability of failure-free operation of the freight wagon at the appropriate level with the help of indicator control boundary states of nodes.
The interpretation of Harrington's desirability function for the case of application to freight cars is given.
It is proposed to assess the quality of the train safety index in the form of correction factor, which is determined by the ratio of the probability of finding a freight wagon in working condition and the design probability of failure-free operation of the freight wagon at the appropriate time interval.
In addition, theoretically, an estimate was given to the inter-repair resource of freight wagons with the suggestion of an expression for its evaluation.
Presented the results of experimental studies in the transition to the system of maintenance and repair on the technical condition with the use of indicator control of the boundary states of the units of freight cars.
When applying the indicator control of the limiting states of the units of the gondola there is a reduction of the influence of the human factor on the technical condition during conducting the system of maintenance and repair.
In the transition to the system of technical power of the state with the use of indicator control of the boundary states of the nodes, the total volume of work on the maintenance of freight wagons is increased by 33 %, while there is a simultaneous decrease in the total volume of work on depot (by 36 %) and overhaul (by 30 %).
Comparing the inter-repair resource of the semi-trailer 12-7023, depending on the run in real operating conditions, is lower by 12 % compared to the prescribed values under the existing system of maintenance and repair.
In the event of a transition to a system of maintenance and repair on a technical condition with the use of indicator control of the boundary states of nodes, the value of the inter-repair resource for the gondola 12-7023 is higher by 7,4 % compared with the normative values established under the existing system of maintenance and repair.
In the transition to a system of maintenance and repair on a technical condition with the use of indicator control of the boundary states of the units of freight cars, it is possible to achieve a reduction in the cost of the lifecycle of the gondola 12-7023 by 13,2 thousand UAH.
