Even since railway vehicles were invented, railway scientists and engineers have been putting a lot of effort in finding the solution to the fundamental conflict between vehicle stability in the lateral plane and vehicle's capability of negotiating curves. Many configurations of railway bogie vehicles have been proposed and applied to minimise the conflict. The purpose of the research project is i) to create new configurations that can decouple the basic conflict, ii) to investigate dynamic behaviour of the new configurations and iii) to conceive a new mechanism that can improve the dynamics of the new configurations. Three configurations of body-steered bogie vehicles have been set up in the research. The sufficient conditions for them to be capable of perfect steering have been derived. They are called perfect steering vehicles when they satisfy these sufficient conditions. Their curving ability, stability and ride performance have been investigated. To overcome the disadvantages of the perfect steering vehicles, the reconfigurable mechanism has been conceived. The improvement in the dynamic behaviour of the perfect steering vehicles with the reconfigurable mechanism has been demonstrated. A computer program has been developed to undertake the simulation. The steering capability of the perfect steering vehicles is much better than that of conventional bogie vehicles. There are two modes of instability in the perfect steering vehicles: low conicity instability and conventional instability in the perfect steering vehicle. The perfect steering vehicles can decouple the conflict between their conventional stability and curving. The improvement of stability and ride performance of the perfect steering vehicles is, however, limited by the low conicity instability. When the reconfigurable mechanism is applied, a body-steered bogie vehicle can become a perfect steering vehicle when on curves and can become a conventional bogie vehicle when in other circumstances. Low conicity instability can be eliminated when the reconfigurable mechanism is used. This class of vehicles possess the advantages of both conventional bogie vehicles and perfect steering vehicles, and thus, provide a very valuable solution for the fundamental conflicts between the stability and steering ability and between ride performance and stability of railway vehicles. The findings in this thesis have great significance in developing perfect steering vehicles.

Following successful implementation of inerters for passive mechanical control in racing cars, this research studies potential innovative solutions for railway vehicle suspensions by bringing the inerter concept to the design of mechatronic systems. The inerter is a kinetic energy storage device which reacts to relative accelerations; together with springs and dampers, it can implement a range of mechanical networks distinguished by their frequency characteristics. This thesis investigates advantages of inerter-based novel devices to simplify the design of active solutions. Most of the research work is devoted to the enhancement of vertical ride quality; integrated active-plus-novel-passive solutions are proposed for the secondary suspensions. These are defined by different active control strategies and passive configurations including inerters. By optimisation of the suspension parameters, a synergy between passive and active configurations is demonstrated for a range of ride quality conditions. The evidence of cooperative work is found in the reduction of the required active forces and suspension travelling. This reveals a potential for reducing the actuator size. Benefits on power requirements and actuator dynamic compensation were also identified. One of the strategies features a nonlinear control law proposed here to compensate for 'sky-hook' damping effects on suspension deflection; this, together with inerter-based devices attains up to 50% in active force reduction for a setting providing 30% of ride quality enhancement. The study is developed from both, an analytical and an engineering perspective. Validation of the results with a more sophisticated model is performed. The lateral stability problem was briefly considered towards the end of the investigation. A potential use of inerter-based devices to replace the static yaw stiffness by dynamic characteristics was identified. This leads to a synergy with 'absolute stiffness', an active stability solution for controlling the wheelset 'hunting' problem, for reducing the creep forces developed during curve negotiation.

<p>У раду је дат нагласак на потенцијалне користи<br />увођењем стратегије одржавања на основу стања<br />возила. Истраживање је базирано на реалним<br />мониторингу кола. Развијени су fuzzy модели за<br />локацију мерних станица на мрежи и предикцију броја<br />деформисаних точкова кола. Дефинисани су<br />параметри за оцену стања склопова железничких<br />возила. Извршено је дизајнирање оперативног центра<br />са умреженим мерним станицама и дефинисана<br />методологија управљања одржавањем железничких<br />возила са предлогом новог модела организације<br />одржавања возних средстава према стању.</p> / <p>U radu je dat naglasak na potencijalne koristi<br />uvođenjem strategije održavanja na osnovu stanja<br />vozila. Istraživanje je bazirano na realnim<br />monitoringu kola. Razvijeni su fuzzy modeli za<br />lokaciju mernih stanica na mreži i predikciju broja<br />deformisanih točkova kola. Definisani su<br />parametri za ocenu stanja sklopova železničkih<br />vozila. Izvršeno je dizajniranje operativnog centra<br />sa umreženim mernim stanicama i definisana<br />metodologija upravljanja održavanjem železničkih<br />vozila sa predlogom novog modela organizacije<br />održavanja voznih sredstava prema stanju.</p> / <p>The paper gives emphasis to the potential benefits of the<br />introduction of maintenance strategies based on the condition of<br />the railway vehicle. The research is based on realistic monitoring<br />circuits. They were developed fuzzy models for the location of<br />measuring stations on the network and prediction of the number of<br />deformed wheel car. Defined parameters for assessment of the<br />state assemblies for vehicles. Executed designing operational<br />center with networked measuring stations and the methodology<br />for maintenance management of vehicles with the proposal of a<br />new model of organization of maintenance of rolling stock<br />according to the state.</p>

As digital tools and technologies, such as AR, VR, Digital Twin, IoT and other interactive visualization technologies are being developed, new opportunities arise to use these to optimize the efficiency of operations, not least in the area of maintenance. One industry where maintenance is of utmost importance is the railway industry, where the goal of having a punctual, reliable and cost-effective railway traffic is dependent on the availability of maintained railway vehicles. The maintenance procedures of the vehicles are performed by technicians, working in depots to fix faults and service the vehicles. However, a lack of resources, poor coordination and information handling, and complex vehicles make the work and procedures of technicians cumbersome. The purpose of this thesis project was to investigate and give recommendations on how digital tools and technologies can facilitate the maintenance of railway vehicles. To do so, a qualitative study has been performed consisting of 12 interviews with technicians and depot staff. The purpose of the study was to understand their main challenges and time-consuming activities. Moreover, the potential use of digital tools and technologies to facilitate the identified challenges has been analyzed to establish recommendations on what tools and technologies can be used and how they should be used to aid technicians. The main challenges and time-consuming activities found include finding and accessing relevant information quickly and easily, understanding the information available, and collaborating with actors for support and expertise. The digital tools and technologies recommended consist of tablets to access information quick and easy, AR to visualize instructions and create an environment for remote support, AI to quickly search and filter information to enhance troubleshooting procedures, Digital Model to visualize vehicle configuration and link and structure information, and lastly, real-time data transfer utilizing eMaintenance technologies to faster receive information about the vehicle and its faults. The results of this thesis project can give direction for future research and the development and integration of digital tools and technologies to facilitate technicians in the maintenance of railway vehicles. / I takt med att digitala verktyg och tekniker såsom AR, VR, Digital Tvilling, IoT och andra interaktiva visualiseringsteknologier utvecklas uppstår nya möjligheter att använda dessa för att optimera effektiviteten inom verksamheter, inte minst inom området för underhåll. En bransch där underhåll är av största vikt är järnvägsbranschen, där målet att ha en punktlig, pålitlig och kostnadseffektiv järnvägstrafik är beroende av tillgången av underhållna spårfordon. Underhåll på fordon utförs av fordonstekniker som arbetar i depåer för att åtgärda fel och serva fordonen. Brist på resurser, dålig samordning och informationshantering samt komplexa fordon gör dock fordonsteknikernas arbete och rutiner besvärliga. Syftet med detta examensarbete var att undersöka och ge rekommendationer hur digitala verktyg och tekniker kan underlätta underhållet av spårfordon. För att uppnå det har en kvalitativ studie genomförts bestående av 12 intervjuer med fordonstekniker och depåpersonal. Syftet med studien var att förstå de största utmaningarna och tidskrävande aktiviteter de stöter på i sitt arbete. Vidare har potentiella användningsområden hos digitala verktyg och tekniker för att underlätta de identifierade utmaningarna analyserats för att fastställa rekommendationer om vilka verktyg och tekniker som kan användas och hur de bör användas för att hjälpa fordonsteknikerna. De främsta utmaningarna och tidskrävande aktiviteterna som hittats inkluderar att snabbt och enkelt hitta och komma åt relevant information, förstå tillgänglig information, samt samarbetet med aktörer för stöd och expertis. De digitala verktygen och teknikerna som rekommenderas består av surfplattor för att nå information snabbt och enkelt, AR för att visualisera instruktioner och skapa en miljö för fjärrsupport, AI för att snabbare söka och filtrera användbar information för att effektivisera felsökningsprocedurerna, Digital Modell för att visualisera fordonskonfiguration samt länka och strukturera information, och slutligen eMaintenance teknik för överföring av realtidsdata för att snabbare få information om fordonet och dess fel. Resultatet av detta examensarbete kan ge en riktning för framtida forskning, utveckling och integration av digitala verktyg och tekniker för att underlätta för fordonstekniker i underhållet av spårfordon.

reducing noise, noise in railway transport, management of application of products for modification of adhesion