The problem of risk assessment in railway transport is presented next to risk analysis and risk evaluation as one of the stages of risk management in the whole railway system. The level of generality in dealing with adverse events in the process of freight transport by rail often results in an inadequate and insufficient response to the upsetting of the acceptable level of risk by those involved in the process. It is common practice to react to the effects of rail incidents rather than prevent them from occurring. The groups of entities involved in ensuring safety in railway transport include rail operators, infrastructure managers, users of sidings, rolling stock manufacturers, manufacturers of devices and railway traffic control systems, designers and entities responsible for maintenance of rolling stock and railway infrastructure facilities. Risk assessment in the rail transport system can be seen as an approach aimed at identifying risks at junctions and on railway lines, including risks arising from operational processes and the actions of other actors in the system whose task is to provide rail freight transport operations. Risk assessment also consists of risk analysis and evaluation. Particularly relevant in this context is the risk profile R the socalled risk scenario representing the pattern of the risk distribution probability and its consequences written in the form of the following pairs [53]:

http://www.ein.org.pl/sites/default/files/2021-03-08.pdf

Risk assessment for rail freight transport operations

Electromagnetics for High-Speed Analog and Digital Communication Circuits: Electromagnetic propagation and radiation

This article describes the issues related to the analysis of the reliability-exploitation of power supply systems in transport telematics devices (PSSs in TTDs). This paper characterizes solutions, which are applied in supply systems, and describes a PSS in a TTD from a main source and a standby one. This enables determining the dependencies denoting the probabilities of the system staying in full ability state, safety threat state, and safety unreliability state. A quality analysis of the PSS in TTD was conducted, and the indicator value of the supply continuity quality was evaluated. This indicator allows the demonstration of continuity quality of power supply (CQoPS) dependency on many quality dimensions, not just reliability. An example demonstrates the calculation of CQoPS factor for both the main and the standby power supply, employing three observations, each influencing the quality. The presented considerations in the field of quality and reliability-exploitation modeling of a PSS can be applied as well in other public utility facilities (including those classified as critical infrastructure). The character of functions performed by critical infrastructure facilities demands an operating continuity of these systems at an appropriate level. The co-first authors of the article once again address the issue of determining CQoPS factor, this time on the basis of modeling using mathematical evidence. TTD is an example in this article, because the presented methods can be used in any kind of system, especially in the power source of critical systems.

Quality and Reliability-Exploitation Modeling of Power Supply Systems

Electromagnetic compatibility assessment in multiconverter power systems - Conducted interference issues

The article presents issues related to the determination of the continuity quality of power supply (CQoPS) for hospital electrical devices. The model describing CQoPS takes into account power redundancy. The uncertainty modeling method based on the certainty factor (CF) of the hypothesis was used to establish the single-valued CQoPS factor. CQoPS modeling takes into account multidimensional quality models and physical stages of power. The quality models take into account seven dimensions that make up CQoPS (availability, appropriate amount, power supply reliability, power quality, assurance, responsiveness, security). The model of power stages includes five of these stages (power generation, delivery to recipient, distribution by recipient, delivery to device, power-consuming device). To date, when designing hospital power systems, the applied reliability indicators revealed limitations because they do not consider all the possible factors influencing the power continuity. Estimating the supply continuity quality with the use of the uncertainty modeling proposed in this article allows for taking into account all possible factors (not just reliability factors) that may affect supply continuity. The presented modeling offers an additional advantage, namely, it allows an expanded evaluation of the hospital supply system and a description using only one indicator. This fact renders the evaluation of the supply system possible for unqualified staff. At the end of the article, some examples of calculations and simulations are presented, thus showing that the applied methods give the expected results.

https://www.mdpi.com/1996-1073/14/2/486/pdf

Method of Estimating Uncertainty as a Way to Evaluate Continuity Quality of Power Supply in Hospital Devices

This article presents the issues related to the functioning and reliability and operational analysis of light-emitting diode (LED) type lighting modules, which are used in the railway technology. These devices operate in different electromagnetic environment conditions in the vast railway area. In the railway area, there are intentional and unintentional electromagnetic (stationary and mobile) interference which affect the operation process of the LED type lighting modules. In the article, the electromagnetic compatibility tests of the lighting module with a converter were carried out with the use of the electromagnetic interference (EMI) receiver of the ESCI3 type and the NNB-51 artificial network. As a result of the carried-out electromagnetic compatibility (EMC) tests, the exceeding of permissible levels of the value of conducted interference emissions was found. The electromagnetic interference of this frequency range has an impact on the operation process of the lighting module with a converter, therefore, by using the appropriate relationships, the values of the probabilities of the system staying in the distinguished operation states were calculated (e.g., in two states of partial suitability distinguished in the LED lighting module due to parallel coupling through reference impedance Z and capacity C). The considerations presented in the article related to the LED type lighting module with regard to electromagnetic interference allow for numerical assessment of different types of (technical and organisational) solutions that can be implemented in order to minimise the electromagnetic interference impact on the system functioning.

Reliability-Operational Analysis of the LED Lighting Module Including Electromagnetic Interference

Mathematical modelling of transient processes in power supply grid with distributed parameters

RailTopoModel is a tool for logical defi ne object model of the data related to railway infrastructure. In April 2016, the standard was released by the UIC (International Union of Railways) as International Railway Standard IRS 30100:2016. RailML has been developed since 2002. It is based on the XML meta-language that is used to defi ne other languages. RailML is used as a data exchange format in railway systems. It includes within its scope data relating to railway traffi c management, rolling stock management, stacking timetables, information for passengers, booking and selling tickets. RailML is currently available in version 2.3. Its upcoming version 3.0 has been especially designed to ensure compliance with RailTopoModel and will be the fi rst practical implementation of this standard. Additionally interlocking schema will be included to the RailML 3.0 schema. Th e authors pay attention to the importance of both RailML and RailTopoModel specifi cation. Th e current state of the standards and their prospects are discussed. Th e authors also present their own soft ware which allows edit and validate RailML fi les.

RailTopoModel and RailML – data exchange standards in railway sector

Synchronizacja czasu na podstawie wzorca w komputerowych systemach sterowania ruchem w transporcie

Railroads and the Rail Traffic Control Systems installed on them in Poland have recently been undergoing rapid technological development (Brodzik, 2019). Modern transportation solutions are susceptible to electromagnetic interference (Paś and Rosiński, 2017). Development of modern railroad infrastructure means not only stations and modern rolling stock, but also safe and reliable train traffic control systems based on the latest telecommunication and IT technologies (Ciszewski et al., 2017). In the last century these technologies were still considered dangerous and were introduced with great fear. Today, computerized systems for controlling railway traffic on the track are becoming the norm. Systems are created as "overlays" for existing relay systems or autonomous systems are built based on microprocessor systems (Burdzik et al., 2017). Today it is hard to imagine a modern control room without computer equipment. The introduction of microprocessor technology to railroad traffic control devices took place at the turn of the century. However, the use of modern radio systems in rail transport is the moment when technology based on the appeared in the world LTE (Long-Term evolution) standard. The development of modern data transmission technologies is integrally connected with the mobility of its users. In the presented article the author has tried to determine the impact of transmission synchronization on the basic transmission parameters of LTE signal (Chrzan, 2021). The convenience of using rail communications for its users is the possibility of uninterrupted access to data transmission services along the entire route of the train. Therefore, the research presented in this article was focused on the use of the public radio communication network for passenger data transmission and data transmission for railroad needs.
The article presents the influence of synchronisation of data transmission in open railway systems using GPS (Global Positioning System) technology. It presents a description of the physical phenomena associated with synchronisation, and presents the author's method for carrying out measurements on railway line No. 4. For this purpose, a diagnostic station was built and special software for data transmission encryption was prepared. The process of synchronisation of clocks with the use of uniform time was adopted as the basis. General measurement results and conclusions resulting from the use of open transmission in railway radiocommunication systems synchronised by the GPS system signal are presented.



Marcin Chrzan

Papers

Reliability-Operational Analysis of the LED Lighting Module Including Electromagnetic Interference

Mathematical modelling of transient processes in power supply grid with distributed parameters

RailTopoModel and RailML – data exchange standards in railway sector

Synchronizacja czasu na podstawie wzorca w komputerowych systemach sterowania ruchem w transporcie

Effect of uniform time on the transmission of signals in rail open systems