Passenger Rail Vehicles Research Articles

Creep slope estimation for assessing adhesion in the wheel/rail contact

AbstractThe UK rail network is subject to costly disruption due to the operational effects of adhesion variation between the wheel and rail. Causes of this are often environmental introduction of contaminants that require a wide‐scale approach to risk mitigation such as defensive driving or rail‐head maintenance. It remains an open problem to monitor the real‐time status of the network to optimise resources and approaches in response to adhesion problems. This article presents an on‐vehicle monitoring method designed to estimate the coefficient of friction by processing data from on‐board sensors of typical rail passenger vehicles. This approach uses a multi‐body physics analysis of a target vehicle to create estimators for both creep force and creep, allowing a curve fitting approach to estimate the coefficient for friction from the creep curves.

Development of a condition monitoring of heat exchangers for corrosion progress and coolant condition

The transport sector, and thus also rail transport, needs to be completely decarbonised by 2050 at the latest. Considering the long service life of rail vehicles, this goal means enormous innovation and growth potential for the vehicle and supplier industry of railway technology in the coming years. This contribution presents the first results of an R&D project to reduce the total cost of ownership of passenger and freight rail vehicles. The reduced life cycle costs can be achieved over the operating life, among other things, with condition monitoring approaches for critical components of cooling systems to enable diagnosis-based maintenance. Based on guided elastic waves, an integrated system is being developed to analyse the depth and position of corrosion damage to heat exchangers in rail vehicles. This method is to be supplemented by a refractive index sensor integrated in the coolant circuit which can be used to derive influences of the coolant condition on corrosion. First, an acoustic measuring technique was put into operation. Suitable piezoelectric transducers were selected and test measurements, including the introduction of artificial damages, along different paths on a representative heat exchanger were carried out and evaluated. Measurement signals can be received over different distances, and a monitoring of larger areas of the heat exchanger seems possible. For the development of the monitoring of the coolant, plasmonically active sensor substrates with a gold nanostructure were produced and installed in a measuring flow cell. In laboratory tests, concentrations of water-coolant mixtures could be distinguished with the refractive index sensor. In the future, the refractive index sensing will be carried out by means of bypass flow measurement. Since the coolant is pumped in a circuit, the sensor system can be attached to one of the inlet/outlet lines.

Modernization of Railway Wagons for Customer Satisfaction and Safety

This article focuses on the assessment of the efficiency of the modernization of railway wagons intended for passenger transport. The modernization of railway wagons is an important step towards ensuring the safer and more efficient operation of railways. However, this modernization is not without risks and, in addition to its many positive effects, it can also bring new challenges in the form of breakdowns and technical problems. Failures in passenger rail vehicles are a challenge facing manufacturers and transport operators, and identifying the relationships between these failures can help to improve the design, manufacture, and maintenance of these vehicles. Passenger rail vehicle failures can vary in nature, whether mechanical, electrical, or inside the vehicle. This paper attempts to provide a comprehensive view of the effectiveness of passenger rail car retrofitting based on the data collected and statistical analyses. The article further focuses on the description of selected rail passenger wagons, describes the analyses of the statistical data using the correlation between the selected rail wagon failures and their significance, in addition to whether the impact of modernization reduces the number of rail wagon failures. The results of this statistical analysis can be used to better understand the impact of modernization on different aspects of passenger transport and will help in making future investment and policy decisions in this area. © 2017 Elsevier Inc. All rights reserved.

Multi-body dynamic modelling and simulations for train crashworthiness design analysis

ABSTRACT One of the most important issues for rail passenger vehicles is on occupant safety through vehicle crashworthiness. Crashworthiness, in terms of rail vehicle designs, is the capability to dissipate the crash energy in such a controlled fashion that the overall damage is inconsequential to passenger space. A case study on a popular city passenger train has been conducted using a multi-body formulation of a three-dimensional, non-linear rigid body dynamic train model. The simulated crash scenario details a one to eight vehicle train in a front-on collision onto a fixed block. The crashworthiness is measured in terms of the degree of impact energy absorption, vehicle deceleration, and passenger injury criteria. The results showed that in a single vehicle, the crash energy management systems (CEMS) adequately compensated for the effects of impact at a crash speed of 44.5 km/h and below. At higher speeds, it is projected that the energy crush zones will need significant structural increases in both its crush length and crush force. An increase in the crush length is normally preferred over the crush force so as to maintain the longitudinal deceleration gradient within a tolerable range to ensure passenger safety. The benefits of computational modelling and simulations should not be underestimated as it allows for a thorough appreciation of a sound appreciation of the crashworthy structures and energy absorbers within any rail vehicle during the initial periods of the design process.

Industry-Driven Approach for ANFIS-Based Intelligent Control Suspension System with MR Damper for Enhanced Ride Quality in Passenger Rail Vehicles for Technological Investigations

Industry-Driven Approach for ANFIS-Based Intelligent Control Suspension System with MR Damper for Enhanced Ride Quality in Passenger Rail Vehicles for Technological Investigations

Modelling and Dynamic Analysis of Adaptive Neuro-Fuzzy Inference System-Based Intelligent Control Suspension System for Passenger Rail Vehicles Using Magnetorheological Damper for Improving Ride Index

The ride comfort and safety of passenger rail vehicles depend on the performance of the suspension system in attenuating vibrations induced by track irregularities. This paper investigates the effectiveness of an Adaptive Neuro-Fuzzy Inference System (ANFIS)-based semi-active controlled suspension system using a magnetorheological fluid damper in reducing nonlinear lateral vibrations of a passenger rail vehicle. A complete rail vehicle model is developed, including the carbody, front and rear bogies, and the passive suspension system’s nonlinear stiffness and damping characteristics are considered from experimental data. The passive suspension model is validated through experiments, and an ANFIS-based controller is incorporated with the secondary vertical suspension system to improve ride behavior. Three semi-active suspension strategies are considered under varying speeds and track irregularities, and their effectiveness is compared to the nonlinear passive suspension system in terms of rms acceleration, rms displacement, ride quality, and comfort. The results shows that the ANFIS-based semi-active suspension system with a magnetorheological fluid damper outperforms the passive suspension system and semi-active strategies in all tested conditions. There is a reduction in rms acceleration by approximately 11.11% to 23.64% and rms displacement by about 5.36% to 32.06%. Moreover, it significantly improves ride quality (9.20% to 31.02%) and comfort (9.96% to 31.50%). The rms acceleration and displacement are reduced, and the Sperling ride index and Percentage Reduction Index values demonstrate that the ANFIS-based semi-active suspension effectively minimizes the impact of rail irregularities and vibrations, resulting in a significant gain in ride quality and passenger comfort.

Modelling and analysis of passenger rail vehicle for the improvement of critical speed using MR damper based semi-active suspension

Developing economies focus to enhance train speed by introducing high speed corridors and upgrading existing rail infrastructure. Higher speed has adverse impact on vehicle stability and ride comfort. Therefore, in order to improve critical speed and ride comfort magneto-rheological (MR) based dampers are used. Here, the lateral dynamics of an Indian passenger rail vehicle is expressed with 17 degrees of freedom model and after validation, it is used to examine the effect of suspension parameters such as damping and stiffness on critical speed. Moreover, a sensitivity analysis is performed and it is found that critical speed is the most sensitive to secondary lateral damping coefficient. Therefore, these dampers are replaced with MR fluid dampers to evaluate improvement in stability and critical speed. The modified Bouc-Wen model is formulated to characterise the behaviour of the MR damper. Herein, two distinct controllers: disturbance refusal and damper force tracking control algorithms are employed to govern the entire system. Measured random track irregularities are applied as an input to simulate the system. The results reveal that the semi-active suspension improves the critical speed by 19.38 km/h (9.89%) when compared to the existing passive suspension, and significantly reduces the vibration responses of the carbody in a wide frequency spectrum at higher speeds of the train.

Simulation of the Thermal Behavior of Cast Iron Brake Block during Braking Maneuvers

In recent years, the interest in monitoring the operating conditions of freight wagons has grown significantly to improve the safety of railway vehicles. The railway research group of the Politecnico di Torino has been working for years on the development of solutions to effectively monitor the operating conditions of passenger and freight rail vehicles. As part of the national Cluster ITS Italy 2020 project funded by Italian ministry of education, university and research (MIUR), the Politecnico di Torino has collected a considerable amount of data thanks to the wired and wireless prototypes developed. The data obtained are used in this paper for the validation and calibration of a finite element (FE) model that simulates the temperature variation of a cast iron brake block due to braking operations of an intermodal freight wagon. The developed model can be a useful tool to predict the temperature at the wheel–shoe interface as a function of the current operating conditions since a direct measurement is not easy to perform.

Combined Multi-Body-System and Finite Element Analysis of a Rail Locomotive Crashworthiness

The modelling and simulation of a passenger rail vehicle locomotive for its crashworthiness are carried out in this paper. It is carried out as an application of combined FEM and MBS analysis using MADYMO. In some parts, the locomotive is modelled as super elements, principal parts are modelled as finite elements and joints are taken as flexible elements considering all external forces along with boundary conditions. The crashworthiness has been determined by striking the locomotive on to a fixed barrier. The simulation results of MFBD model at 25 kmph is benchmarked to the EN 15227 for validation of this technique. Once the model is validated, it is used for the locomotive crash analysis of crashworthiness behaviour at a different impact speed of 100 kmph, 160 kmph, and 225 kmph. Local buckling is observed at multiple points that restrict locomotive continuous damage characteristics. The results predict an increase in the speed of impact, more plastic deformation for the locomotive frontal part. The peak deformation is nearly 8.23 m observed at 224 kmph velocity.

Theimpact of the Coatingsystem for Rolling Stock on Fire and Anti-Corrosion Properties

Abstract Paper discusses results of experimental research aimed at developing of an anti-graffiti paint system for passenger rail vehicles which fulfill the requirements of coating flammability characteristics according to EN 45545-2+A1:2015-12. The most important element of effective fire protection is the use of fire-resistant materials limiting the spread of fire and smoke in rolling stock. Coating system has to meet requirements in the field of fire properties with maintaining the desired performance parameters, such as protective and decorative properties. The development works that are the subject of this article were started by testing standard coating system flammable properties. Next stage of research was to modified fire properties of polyester putty. The tests have shown the effectiveness of the use of a protective paint that allows meeting the requirements in the field of fire safety. In addition, measurements of the corrosion resistance of anti-graffiti coatings were made.

Semi-active Control to Reduce Lateral Vibration of Passenger Rail Vehicle Using Disturbance Rejection and Continuous State Damper Controllers

In this paper, Bouc–Wen type magnetorheological fluid damper has been used to monitor the ride quality of a prevailing rail vehicle in lateral vibrations. Modelling of the rail vehicle is done in such a manner that it has an entire 9 degrees of freedom by significant considerations of lateral, roll and yaw motions of the car body, rear, and the front chassis. 200 km/h is considered as train speed for tracks with two varying disturbances. A system consisting of multibody in VI-rail software is provided by a track input and ergo, wheel response it obtained. SIMULINK (software) is responsible for the representation of the motions of the wheel as mathematical models. Two different types of analysis are done firstly with conventional passive lateral damper and secondly with semi-active MR lateral damper in subordinate suspension. To diminish lateral vibrations, the disturbance refusal and non-stop state controller algorithms were executed to manage the damper force. Results acquired are in the form of acceleration and displacement of the center of mass of the body under consideration is done by comparing in terms of reduction indices of their vibrations. A significant improvement in the index is seen in which a semi-active lateral damper is mounted. The results show that the proposed system significantly improves both, the vibration attenuation ability and the ride quality of the vehicle.

Crashworthiness of passenger rail vehicles: a review

In this article, based on a broad review of the literature, a comprehensive overview of the global state of the art in the development of rail vehicle crashworthiness is presented. Following large number of studies on rail vehicles, this article presents a review of the crashworthiness of passenger rail vehicles from the aspects of research approaches, accident investigations, mechanism analysis of occupant injuries and train damage, strategies of occupant protection, and crashworthiness design (crash energy management design) and performance of rail vehicles in collisions. Finally, some conclusions and recommendations for future research are presented.

Comparison of motor coach exhaust emissions in real operating conditions for different testing procedures

The article discusses the results of applying real driving emissions (RDE) testing methods in measuring the exhaust emissions of a passenger rail vehicle. Portable Emissions Measuring Systems (PEMS) were used to measure the exhaust emissions from a motor coach in real operation, performed on a test track for selected drive cycle parameters. The road emission values of exhaust components have been calculated and compared to road vehicles and road exhaust emission limits based on the legal norms. The assessment was concluded with a comparison of the environmental cost, in terms of exhaust emissions, of transporting passengers using the tested rail vehicle relative to alternative road transport, based on measurements in real operating conditions.

Estimation of ambient temperature impact on vertical dynamic behaviour of passenger rail vehicle with damaged wheels

Maintenance and repair specialists of rolling stock face the problem related to accurate and reliable assessment of the vibrations of the car body of passenger rail vehicle, caused by wheel damage, and its impact on passengers. Another important aspect is to deter-mine the permissible speed at which the passenger car with wheel damage could move to the nearest station or depot without badly damaging the rails. The purpose of this research is to examine the dynamic processes of the interaction of the passenger car chassis with the railway track using a newly developed mathematical models called the “Passenger Car - Track” system. During the simulation, the dynamic characteristics of the track, bogies and car body in different season temperature were estimated. The validation of theoretical results was obtained based on the field tests of the test train as well as the results of measurements of changes in track stiffness temperatures. Finally, conclusions and suggestions are presented.

Multi-objective design optimization of a rail HVAC CO2 cycle

In HVAC system design for passenger rail vehicles minimization of objectives on merchantability (initial costs), integration (equipment mass, volume), and operation (electric power demand, noise emissions) becomes increasingly important. Identification of appropriate process and component design parameters is a significant engineering challenge, particularly for emerging R744 (CO2) refrigerant cycles.In this work the sizes of the compressor, evaporator, gas cooler, cooler fan, and internal heat exchanger, plus the high pressure level and the cooler air flow rate of an R744 cycle were subject to multi-objective genetic optimization. Computationally inexpensive artificial neural networks were used as interface between different computation tools. As a result a set of Pareto-optimal R744 cycles was obtained to support the design engineer. For minimum volume and mass (153 l, 169 kg), total electric power demand was 9.2 kW. Vice-versa, minimum power demand (6.9 kW) yielded a large (272 l), heavy (198 kg), and expensive system.

Modeling, Simulation, and Testing of Switching Surge Transients in Rapid Transit Vehicles DC Power Systems

During the operation of dc rapid transit systems, the rail passenger vehicles are subjected to surge transient events that can damage the on-board equipment and cause service interruption. During the testing phase, vehicle manufacturers must demonstrate the performance of the vehicles under the specified transients. However, system testing is generally not available during design. Engineering analysis must be performed to ensure that the design will meet the transient requirements, and that the overvoltage and overcurrent protective devices are coordinated on a system level. In response to these design challenges, detailed time-domain simulation models of a switching surge transient generator and the vehicle equipment have been developed and validated experimentally. These models are used to evaluate vehicle system parameters sensitivity, as well as to provide design guidelines for increased vehicle power system safety, reliability, and availability.

The dynamic behavior of pneumatic vibration isolators

The ubiquity of pneumatic vibration isolators, especially in heavy road vehicle suspensions and in passenger rail vehicle secondary suspensions, has boosted research interest in these systems. Thermodynamic models have been used in order to inform and support engineering design decisions. Most models assume that the air inside the system undergoes a polytropic transformation during the compression/expansion cycle, but the necessary polytropic index value is often guessed at and seldom measured. This paper presents measured polytropic indexes that contradict the traditional assumptions with respect to its value. On a different note, the work presented in this paper also investigates the air flow through the restrictor (a component that is often used in suspension applications to introduce damping and adapt the frequency response function). The results show that this flow can be analyzed with utterly simple models.

Disturbance rejection and force-tracking controller of nonlinear lateral vibrations in passenger rail vehicle using magnetorheological fluid damper

In this article, an existing railway vehicle is modelled as a full-scale nine-degree-of-freedom system considering lateral, yaw and roll motions of the car body and the front and rear bogies. Moreover, nonlinear stiffness and damping functions of passive suspension systems are extracted from experimental data. In order to improve the ride quality of the rail vehicle, a magnetorheological damper is integrated into the secondary lateral suspension system. Parameters of the magnetorheological damper depend on current, amplitude and frequency of excitations. Tracks with five different types of irregularity are considered for train speeds of 160 and 200 km/h. The track input is given to the multibody system in VI-Rail software and the wheel response is generated. The wheel motions are input to the mathematical model represented in MATLAB/Simulink. Four types of analyses are performed with (1) conventional passive lateral damper, (2) semi-active low, (3) semi-active high and (4) semi-active controlled MR lateral damper in the secondary suspension. Disturbance rejection and force-tracking damper controller algorithms were applied to control the desired force to reduce the lateral vibration. The results clearly imply that the proposed semi-active suspension system improves the vibration attenuation and ride quality of the vehicle.

Crashworthiness Analysis and Energy Absorption Enhancement of a Passenger Rail Vehicle

Crashworthiness Analysis and Energy Absorption Enhancement of a Passenger Rail Vehicle

Identification of representative operating conditions of HVAC systems in passenger rail vehicles based on sampling virtual train trips

Simulation-driven development and optimization of heating, ventilation and air-conditioning (HVAC) systems in passenger rail vehicles is of growing relevance to further increase product quality and energy efficiency. However, today required knowledge of realistic operating conditions is mostly unavailable. This work introduces methodologies and tools to identify representative operating conditions of HVAC systems in passenger rail vehicles. First a Monte-Carlo-simulation approach was employed to acquire a large set of close-to-reality HVAC operating conditions based on simulated train trips. Sampling simulated train trips bypassed the issue of unavailability of appropriate real-world data. Furthermore the approach allowed high flexibility in considering HVAC-relevant factors associated to different categories of trains, rail networks, operation profiles and meteorological conditions. Second, algorithms and methodologies such as k-means clustering and an adapted Finkelstein–Schafer statistical method were implemented to identify representative HVAC operating conditions from the sampled dataset. Final results comprise a set of time-independent HVAC operating points with associated frequencies of occurrence (ROC-points) as well as a set of time-domain signals for representative days (ROC-signals). These results are input for stationary or dynamic system-level simulations, which are used to support design decisions. The developed methodology was exemplarily applied to urban/suburban trains in Switzerland.