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The article analyses the performance characteristics and operating costs of the three types of trolleybuses equipped with alternative energy sources, which are used by the MPK (Municipal Transport Company) in Lublin. The selected applications are adapted for driving off traction in emergency mode as well as servicing the regular route. Two of them are based on electrochemical batteries and one uses a system with an electric generator driven by an internal combustion engine.

Each of the steps of generation and conversion of electricity is related to the occurrence of losses. These arise in the production of energy, at transmission to the public power grid, during the processing stage at the traction substations supplying the overhead line and in the overhead line. Moreover, the electric vehicle drives have limited energy efficiency.The efficiency of electricity generation and public HV transmission systems is the subject of many scientific publications in the field of power systems. [Scarpellini et al. 2013; Sweet- Research Article MEASUREMENT AND ANALYSIS OF TRANSMISSION LOSSES IN THE SUPPLY SYSTEM OF ELECTRIFIED TRANSPORT ABSTRACTThe issue of electric energy saving in public transport is currently becoming a key area of interest, a fact connected with both an increase in society's environmental awareness and a rise in the prices of fuel and electricity. Electricity can be saved by reducing transmission losses in the supply system. The article presents a method of measurement and analysis of transmission losses in the supply system of electrified public transport on the example of trolleybus transport in Gdynia and Lublin in Poland.

The aim of this study was to analyze the impact of the categories of bus downtime caused by the necessity of their repair on the availability indicator. A retrospective study covering 12 years of bus operation was carried using the selected municipal transport company as an example. The share of the selected categories of downtime in the total time of vehicle downtime was analyzed. The Spearman’s rank correlation coefficient was used for the analysis. The research covered seven makes and types of buses and six categories of downtime. A ranking of the downtime categories was developed according to the criterion of the statistical dispersion of stoppage time as a measure of their unpredictability. It was shown that categorized unavailability was strongly dependent on the rank of downtime and loosely dependent on the age of buses. In practical applications, the test results may be useful in improving the fleet maintenance processes, selecting the make of new buses or development of models for safety margin availability.

The development of public transport systems presently focuses on sustainability. In this situation, the issue of user (passenger) migration has become important to the transport company as a service provider. This paper presents an integrated model of the operational risk of vehicle incapacity, including the following: costs of incidental repairs, costs of unplanned downtime and costs resulting from potential user migration. The paper presents the results of operational research on buses of two makes over a period of 6 years, in the mileage range of 0–420 000 km. The authors have determined the risk as a regression function of operational mileage to estimate the optimum life cycle. The quality of the vehicle was assessed using the criterion of the maximum cost of the operational incapacity risk being equal to the current residual value of the vehicle. The research results confirmed the suitability of the integrated risk model for a comparison of vehicle makes and assessment of their reasonably foreseeable life cycle in a balanced carrier-vehicleuser system.