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The main task of a railway undertaking is to transport passengers and/or freight safely and cost-effectively. This task is enabled by the use of energy carriers. Since most of the rolling stock operated by major railway undertakings is electric, an additional area of activity involves managing electricity consumption and supply processes. Every business activity entails risk, including energy-related operations. The aim of this paper is to develop a method for assessing the risks associated with a railway undertaking from an electrical perspective and, based on this method, to perform such an assessment. As part of the research, a universal risk assessment approach based on the M_o_R® (Management of Risk) methodology was developed. Risk identification was performed using the risk description principle, followed by risk estimation. The study proposes national-level variables and a procedure for determining them using publicly available data. Risk assessment and process evaluation were carried out using Monte Carlo simulation as a probabilistic tool for uncertainty propagation. As a result, the potential losses and gains that a railway undertaking may experience from an electrical perspective were estimated for scenarios in which the identified risks materialize.

The issues addressed by the article concern the assessment of energy efficiency in rail transport, resulting from the proper organization of rail traffic. The problems related to energy consumption and, thus, the negative impact of rail transport on the natural environment are highly significant in terms of the green deal concept, climate change and sustainable development. In this article, energy efficiency is investigated in the context of minimizing the energy consumption necessary to satisfy a specific transport requirement. The essence of this article is to present an approach to energy-efficient planning of rail freight traffic. This article aims to develop a method covers the allocation of railway vehicles dedicated to freight traffic (locomotives and railcars) to perform a defined transport task, taking into account the energy efficiency assessment of the solution, routing the train launched with regard to the accomplishment of the defined transport task on the railway network, and determining the conditions of transport for a defined transport task, taking into account the allocated rolling stock (locomotives and railcars) and the route. In this article, based on the presented state of knowledge, a decision-making model has been proposed, including the model’s parameters, the values being searched for, indicators for assessing the quality of the solution, as well as the limitations and boundary conditions of the problem. The function of minimizing the energy consumption necessary to transport a shipment within the railway network (determining the energy efficiency of the proposed solution) has been proposed as the criterion. In addition, a description of the proprietary method of selecting rolling stock for accomplishing tasks, based on the assessment of the energy efficiency of the solution and a case study illustrating the operation of the method on the example of the area of Poland, has been presented.

Development of railway infrastructure at the turn of the 20th and 21st centuries, as well as the speeds of trains in passenger and freight traffic are the result of improving the structure of modern rail vehicles and railway infrastructure optimization. The structure of the railway surface, which enables high speeds and transferring ever greater loads and pressures of up to 25–30 t/vehicle axis, must meet very strict strength and durability requirements. This paper discusses mathematical and numerical tools used in simulation and experimental tests of railway surfaces, as well as its selected elements. Issues addressed in this paper concern, among others, modeling of the railway track, calculations related to its static and dynamic loading, and simulation of the technological process of selected elements of railway turnout. Selected results of the simulation tests on numerical models showing their behavior under different loads are also presented in this paper. The concept of symmetry is included in the possibility of applying the method described in the article both for testing other sections of railway lines, as well as for testing other elements in which stresses occur.

One of the assumptions made during the modernization process of diesel shunting locomotives is the replacement of a diesel traction motor with a DC generator with an electric asynchronous traction motor. The article aimed to develop a method of selecting energy-efficient parameters of an asynchronous electric traction motor for diesel shunting locomotives, which will ensure that its operating energy efficiency will be as high as possible. The method was verified on the example of a locomotive series ChME3 (ЧMЭ3, ČME3, ČKD S200). It has been found that using a traction asynchronous electric drive on a ChME3 locomotive, its efficiency increases in comparison with DC electric motors by 3–5% under the long-term operation modes and by 7–10% during locomotive operation with traction at the adhesion limit. Using a new traction gearbox with a higher gear ratio expands the speed range in which the asynchronous traction drive operates with a high-efficiency factor. It is effective to use a traction asynchronous electric drive to modernize ChME3 diesel locomotives in case of their use under the modes requiring the implementation of maximum traction forces at low speeds. A further increase in the efficiency of the traction asynchronous electric drive is possible based on the optimal design of the wheel-motor unit and the asynchronous traction electric drive.

This article presents research results on a multi-aspect assessment of delivery planning in the urban transport network. The distribution of goods and the operation of a network of small services in urban agglomerations is a very important decision-making problem. This is due, on one hand, to the dense development of urban areas and, on the other hand, to the increasing restrictions on minimizing harmful exhaust gases emitted by cars. Hence, many researchers are looking for decision support methods that take into account many partial points of view in the field of transport services for small service companies located in urban areas. The authors present a method of multi-criteria decision support in the planning of urban supplies, taking into account the minimization of emissions of harmful compounds (carbon dioxide, nitrogen oxides, and particulate matter), the cost, time, and amount of ecosystem exposure to these compounds. An important aspect of this research was to identify partial criteria of the decision support methodology and the definition of decision variants. The partial criteria included cost, time, and the amount of exposure of the ecosystem to harmful compounds. The Saaty method was used to determine the weights of the criteria.

Nowadays, apart from travel time and cost, more and more attention is paid to ensuring that ecological footprint of the means of transport used for a journey is as small as possible. Therefore, it is reasonable to look for methods and solutions that will allow planning communication connections according to the principles of sustainable development. The aim of the article was to present mathematical model of the proecological distribution of traffic flow into a network, together with a determination of how the amount of emissions of harmful compounds for rail transport will be calculated (based on amount of energy necessary for movement, calculated on circumference of the wheels). The model has been verified on real data. The traffic flow was distributed over a selected communication route: Warszawa—Gdansk, where the criterion was minimization of total carbon dioxide emissions. An evolutionary method implemented in Microsoft Excel was used to solve the optimization problem. For the analysis of only the fastest connections, the railway one was the optimal from the point of view of the adopted criteria. After the train capacity was exceeded, air and car connections were loaded. Based on the research, a function that represents the amount of carbon dioxide emissions in the analyzed traffic route depending on the size of the traffic flow was developed.

Decisions concerning development of the transport system in district, city or region should be undertaken after careful analysis. One of the methods to carry it out is utilization of a computerized traffic model which is prepared in specialized software - e.g. in the VISUM. Traffic model allows to predict the effects of proposed changes in configuration of the transport network, in traffic restrictions or in effects of changes in anticipated spatial development of the area. The models can be created for different applications - e.g. only for research the modal split in passenger traffic with taking into account all the possible ways of movement, for research the distribution of selected types of transport means in transport network, or for research investment needs in transport infrastructure development. In each of these cases there is a need to develop a model of the transport network as well as demand model. The article presents an approach to modeling cycling in cities using the PTV VISUM. Were presented solutions for the development of the network model, demand model (including travel generation and spatial travel distribution), model of traffic distribution on the network, as well as in the field of verification, validation and calibration. In addition, it describes the use of described approach to develop a cycling model for Warsaw. This model is one of the elements of the Transportation Model of Warsaw Agglomeration 2016 which is result of work carried out by the consortium: PBS, Cracow University of Technology and Warsaw University of Technology. Model developed as part of this project is a tool for supporting planning of cycling in Warsaw. Described approach can be used to develop a model of cycling for any area (of course in case of having relevant data).

The correct operation of the continuous welded track requires diagnosing its condition and preparation of track metrics requiring measurements of displacements of rail under operation. This is required as there are additional thermal stresses in the rails with values depending on the temperature changes of the rails. Therefore, the climatic conditions are important. This paper presents the original effective analytical method for diagnosing the condition of continuous welded track based on experimental research. The method allows for an appropriate repair or maintenance recommendation. In the experimental research, the authors considered track diagnostic conditions for two conditions: track under load and track without load. This paper presents empirical formulas for calculating rail temperature and longitudinal force based on ambient temperature, developed from long-term measurements. The formulas were developed for a track located on a straight section—both for a rail loaded and unloaded with a passing train under the following conditions: 60E1 rail, not on an engineering structure, conventional surface, wooden sleepers and very high train traffic load. The obtained results in the value of the correlation coefficient R2 ≥ 0.995 attest to very high accuracy of the calculations performed with the method proposed by the authors.

Nowadays, thanks to funds coming from various sources -including the European Union, intensive modernization and revitalization works regarding railway transport infrastructure are carried out. These works include both the railway surface and the change in the way of conducting railway traffic on both open lines and operating control posts. During modernization and revitalization, efforts are being made to introduce more and more new solutions in both mentioned areas. However, there is no multi-criteria method that would allow to assess which method seems to be the most advantageous. The aim of this article is to present a multicriteria method of choosing the method of conducting railway traffic on the open line for modernized and revitalized railway lines. It should be noted that the basic group of criteria in the method applies to the organization of railway traffic. The article discusses the basic issues regarding the modernization and revitalization of railway lines, ways of conducting railway traffic on open lines and multi-criteria assessment methods. A multicriteria method for selecting the method of conducting trains was presented and it was verified for a selected railway line in Poland.

The most important problems concerning the organization of railway traffic is continuous provision and systematic improvement the level of safety of services provided by railway transport enterprises. This safety results from many factors – including condition of the infrastructure, state of superstructure or the way of conducting railway traffic. This article covers railway infrastructure within its scope. In this regard include, among others take appropriate actions to monitor its condition. One of the methods may be the audit of the railway line in terms of infrastructure condition. The purpose of the article is to present the method of railway line audit in the area of infrastructure. The concept of railway line audit from the point of view of infrastructure status was defined in the paper. The audit method was presented along with the identification of problems that may occur as a result of the audit and suggestions for solutions to these problems. The presented method was verified for a selected railway line in Poland railway line No. 12 Skierniewice – Łuków. The possibilities of improving the condition of this line were proposed together with the estimation of the amount of expenditures necessary to make therefore and time gains achieved through improvement.