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This paper presents the testing methodology of specimens made of layers of titanium alloy Ti6Al4V in dynamic impact loading conditions. Tests were carried out using a drop-weight impact tower. The test methodology allowed us to record parameters as displacement or force. Based on recorded data, force and absorbed energy curves during plastic deformation and sheet perforation were created. The characteristics of the fractures were also analyzed. The impact test simulation was carried out in the ABAQUS/Explicit environment. Results for one, two, and three layers of titanium alloy were compared. The increase in force required to initialize the damage and the absorbed energy during plastic deformation can be observed with an increase in the number of layers. The increase in absorbed energy is close to linear. In the simulation process, parameters such as Huber–Mises–Hencky stress value, equivalent plastic strain, temperature increase, and stress triaxiality were analyzed.

This study is an attempt to investigate possible applications of rubber granulate SBR (styrene-butadiene rubber) produced from recycled waste tires as an elastic cover for prototype rail dampers, which are aimed at reducing the level of railway noise emitted in the environment. The authors present laboratory procedures and discuss the results of several experimental tests performed on seven different SBR materials with the following densities: 1100, 1050, 1000, 850, 750, 700 and 650 kg/m3. It is proven that rubber granulate SBR produced from recycled waste tires, can be used as an elastic cover in steel inserts in rail dampers, provided that the material density is not lower than 1000 kg/m3. In the conducted tests, samples of the materials with high densities exhibited good static and dynamic elastic characteristics and had sufficient operational durability.

In the present paper results of the tests for fatigue strength and resistance to severe environ-mental conditions performed on several prototypical under sleeper pads (USP) are presented. The work includes results of the static and dynamic tests carried out on samples of three materials, which were used to produce the USP. The fatigue tests were performed up to 500 thousand load cycles and they aimed at determining which of the analysed USP have favourable properties, taking into account their potential application as the elements used for reduction of stresses in the ballast – especially in the ballast layer directly under the sleeper – and reduction of the material and acoustic vibration emitted to the railway track’s surrounding (vibration and noise). In the climatic tests that were aimed at determining the influence of severe environmental conditions on the properties of USP, the samples were attached to concrete blocks and immersed in water for 24 h and then placed in a climatic chamber, where they were subjected to freeze-thaw cycles. The results show that both the fatigue and climatic tests have influence on the damping-related parameters of the USP, what affects the effectiveness of the vibration isolation.

In the present paper results of pull-off tests performed on several prototypical under sleeper pads (USP) attached to the concrete body are presented. The pads had been tested beforehand for resistance to severe environmental conditions. The USP are used in the ballasted track systems to reduce the material and acoustic vibration emitted to the railway track’s surroundings (vibration and noise) and to reduce stress in the ballast – especially in the ballast layer directly under the sleeper. The presented values of tested bond strength of the USP were compared to the requirements used by foreign railway infrastructure managers.

The present paper is aimed at the analysis of under ballast mats (UBM) which are used in ballasted track structures as vibration isolators and to protect the ballast layer against fast degradation. The mats were tested in the laboratory and afterwards a novel 4-DoF mechanical model of the track structure with UBM was developed. The novelty of this study consists in the comparison of two testing procedures: a procedure based on the popular German standard DIN 45673-5 and a new European standard EN 17282, released in October 2020. Major discrepancies were demonstrated in the determined values of the static and dynamic characteristics using both approaches—especially in reference to the mats with higher stiffness.

The present paper is dedicated to the analysis of under sleeper pads (USP), which are resilient elements used in ballasted track systems as vibration isolators. Four types of USP are considered. The authors present the results of laboratory tests, which are then used as input values for the finite element (FE) and mechanical model of the structure. A special focus is put on the description of an original four-degree-of-freedom (4DoF) mechanical model of the system that includes a fractional rheological model of USP. Using the proposed approaches, the dynamic characteristics of under sleeper pads are determined, and conclusions on vibration isolation effectiveness are drawn.

The paper presents results of the laboratory tests made for the prototype resilient under sleeper pads in the Warsaw University of Technology laboratory unit. These pads are dedicated to reduce vibrations transmitted to the vicinity of the railroad and to improve the resistance of the railroad structure. The laboratory testing program was carried out for elastomeric materials (polyurethane and rubber based) due to the PN-EN 16730 standard. The obtained values of the key parameters were used in order to determine the insertion loss vibration level by applying analytical method. The paper presents the influence of selected parameters i.e. static and dynamic moduli on the reduction of vibration and structure-borne sound level.

The paper is devoted to testing, modelling and performance assessment of vibration isolation products applied in ballastless track structures. In the first part of the paper, results of laboratory tests of vibration isolation products, such as under slab mats (USM) and under block pads (UBP) are summarised. On their basis, the Fractional Zener Model (FZM) is calibrated and it is shown that the model properly covers the stiffness and damping characteristics of tested materials in a wide frequency range. Then, results of the finite element analysis performed in a frequency domain using the Abaqus code are presented, taking into account the frequency-dependent material characteristics. The analysis concerned a ballastless track structure with a discrete system of rail fastening (embedded block system – EBS) laid on USM. The proposed approach was compared with the simplified one, in which the frequency-dependence of material properties is neglected. The presented modelling methodology, based on outcomes of laboratory tests, makes it possible to compare various vibration isolation systems in a short time. Consequently, it can be considered as a useful engineering tool.

The present paper focuses on laboratory tests of fatigue strength of prototype under ballast mats (UBMs), carried out according to the procedure described in the new European standard EN 17282, which was released in October 2020. The mineral wool-based mat revealed significant differences in the values of static and dynamic characteristics, measured before and after the fatigue tests. The elastomeric mats based on recycled materials (SBR granulate and fibers) turned out to have had sufficient durability and effectiveness of protection against vibration caused by railway traffic. The values of static and dynamic bedding moduli, determined before and after the fatigue tests, were used to develop a viscoelastic rheological model of the vibration isolator with the use of fractional derivatives. Using this original model of the ballasted track system with four degrees of freedom, a significant influence of cyclic loading on the level of vibration suppression (insertion loss factor) was demonstrated. The analytical model confirmed that the mats with variations of bedding moduli exceeding 10% should not be used as resilient elements.

The paper presents essential static and dynamic properties characterizing resilient mats for vibration isolation of railway tracks. The attention was focused on under-ballast mats and slab-track mats used in the construction of railways. Referring to this type of mats, selected test procedures for determining the values of parameters describing static and dynamic characteristics were described. Basic classification of vibration isolation mats was presented in the paper. Moreover, the essential functional and operation features related to various types of mats were given. Some theoretical aspects concerning viscoelastic dynamic modelling of resilient track elements were also outlined. In order to characterize requirements and methodology of research for resilient mats in railway tracks, German Standards [1–3] were used herein.

The paper presents an overview of vibroacoustic isolators used in railway tracks to reduce negative effects from railway traffic. These include single components or their assemblies, with different material characteristics and location in the track structure due to track structure type (ballasted or ballastless track system). The reduction of negative effects relates mainly to the reduction of vibration and structure-borne noise. The practical solutions for railway structures include various components that perform different functions at the same time: vibroacoustic isolation and mechanical function to ensure safe and durable use of rail track (i.e. rail fastening systems, rail supporting structures). The main goals of this paper are systematization and description of basic material characteristics of vibroacoustic isolators applied sufficiently close to the place of vibration generation during the movement of rail vehicles.

The paper presents findings from research project Mobis which is aimed at developing a method of assessing safety of unsignalised pedestrian road crossings using video image analysis. Pedestrian and vehicle traffic has been recorded at selected zebra crossing sites in Warsaw and Wrocław, before and after installation of active signage systems SignFlash and Levelite. Speeds of approaching vehicles were measured and drivers’ behaviour was classified using video analysis.The paper presents a comparison of effectiveness of systems such as SignFlash and Levelite based on changes in the mean and standard deviation of vehicle spot speeds as well as changes in speed profiles of vehicles approaching the crossings.Results indicate that both SignFlash and Levelite active signage reduce mean vehicle approach speeds and have a positive impact on drivers’ behaviour.

In many fields of Civil Engineering Finite Element Analysis (FEA) is widely used at the design stage. In case of railway trackbed design we can take into account various geotechnical and structural problems. In many countries the resilient modulus is used as a key parameter for evaluation of design correctness. Knowledge of the module itself does not prove the correctness, because for example it does not account slope stability. These phenomena, which are crucial to the subgrade behavior, can be described using FEM models. This article presents a simplified numerical model of railway trackbed layered structure. The stress and strain fields were analyzed and compared with estimation using available empirical formulae.

The paper presents selected theoretical aspects concerning viscoelastic dynamic modelling of resilient elements used in railway tracks. In order to characterize the research methodology for resilient mats in railway tracks, German Standards [1-4] are used herein. The main goal of the paper is to demonstrate the procedure of insertion loss calculation for a single degree of freedom truck system containing under-ballast mats. Selected results of certain dynamic characteristics of resilient truck systems (transmissibility, Bode and Nyquist plots etc.) are also discussed. The results of calculations visualized in graphs, were obtained by using own applications written in programming language MATLAB.

The paper describes the essential functional and operational features of the Under Sleeper Pads (USPs), used in ballasted rail track systems. The overview of appropriate test methods for determining the values of relevant parameters for the purposes of using vibro-acoustic isolators was presented, with special attention drown to the changes resulting from the introduction of the PN-EN 16730 standard in this field. Due to the given testing procedures for USPs, selected examples of the normative testing methods of the USPs’ carried out at the Faculty of Civil Engineering of the Warsaw University of Technology with the results were presented.

The paper presents laboratory methods of testing the prototype resilient mats, used in rail track systems in order to reduce vibrations transmitted to the vicinity of the railroad and to improve the resistance of the railroad structure. The laboratory testing program was carried out for elastomeric materials (polyurethane based). The key parameters being investigated in the Warsaw University of Technology laboratory unit were used in order to determine the insertion loss vibration level by applying analytical method. The paper presents the influence of selected parameters i.e. static and dynamic moduli on the reduction of vibration and structure-borne sound level – i.e. the value of insertion loss parameters.

Pedestrian fatality rate in Poland of 30 deaths per year per million population was the second highest among the EU countries in 2013. In the years 2007-2013 some 13% of pedestrian fatalities and 26% of injuries occurred at unsignalized pedestrian crossings where pedestrians should theoretically be safe. The paper presents results of research project MOBIS which was aimed to develop surrogate safety measures based on detection of dangerous situations or near-accidents. Within the project, pedestrian and vehicle traffic was recorded at four pedestrian crossings in Warsaw and Wrocław, for a period of approximately 2 months per crossing. Motion trajectories of vehicles and pedestrians were determined and certain parameters describing the pedestrian-vehicle encounters calculated. The average number of such encounters was over 1000 per day in both Warsaw and Wrocław. Dedicated video and data analysis algorithms were used to extract interactions that met certain criteria. To this end the following parameters were used: velocity profiles of pedestrians and vehicles, minimum distance between the participants, deceleration during braking, etc. These variables were used to develop surrogate safety indicators for pedestrian-vehicle encounters. A classification of encounters based on the characteristics of pedestrian-vehicle interaction is also proposed. Within the project certain solutions for increasing pedestrian safety at road crossings were installed and evaluated. These included speed cushions and flashing lights warning the drivers about pedestrian presence that were either mounted on traffic poles or embedded in the road surface. The evaluation of these solutions will be based on surrogate safety measures developed in the MOBIS project.