This paper deals with the analysis of the operating conditions of traction drives of the electric locomotives with asynchronous traction motors. The process of change of the catenary system voltage was found to have a stochastic character. The method of current controller synthesis based on the Wiener–Hopf equation was proposed to enable efficient performance of the traction drive control system under the condition of the stochastic nature of the catenary system voltage and the presence of interferences, when measuring the stator current values of the tractor motor. Performance simulation of the proposed current controller and the current controller used in the existing vector control systems of the traction drives used in the electric locomotives was implemented. The results of the performance simulation of the proposed current controller were compared with the performance of the current controller in existing vector control systems of the traction drives. The results are applicable to the design of vector control systems of traction drives in electric locomotives and to the study of the influence of performance of electric traction drives in electric locomotives on the quality indicators of the power supplied by the traction power supply system under the actual operating conditions of the locomotive.

Bicycle riders are among the highest risk group in traffic. A cyclist simulation study captured kinematics and injuries to legs, pelvis, neck, and head for one human body size. We analyzed the number of parameters (forces acting on left and right tibia, head injury criterion, neck tensile force, neck shear force, and pelvic acceleration) for each of the four different cases: bicyclist ride out-residential driveway, motorist overtaking-undetected bicyclist, bicyclist left turn-same direction, and bicyclist right turn-opposite direction. The comparison of simulation outcomes for leg injuries with official hospital records has shown a very good correlation in terms of injury severity prediction. This study concludes that if countermeasures to prevent fatal cyclist injury in car impacts were to be concentrated on mitigating head and neck impact to the windscreen of the car, a dominant share of fatal cyclist crashes and severe traumatic head injury cases at collision speeds exceeding 40 km/h could be prevented.

Two trends could be observed in the evolution of road transport. First, with the traffic becoming increasingly intensive, the motor road infrastructure is developed; more advanced, greater quality, and more durable materials are used; and pavement laying and repair techniques are improved continuously. The continued growth in the number of vehicles on the road is accompanied by the ongoing improvement of the vehicle design with the view towards greater vehicle controllability as the key traffic safety factor. The change has covered a series of vehicle systems. The tire structure and materials used are subject to continuous improvements in order to provide the maximum possible grip with the road pavement. New solutions in the improvement of the suspension and driving systems are explored. Nonetheless, inevitable controversies have been encountered, primarily, in the efforts to combine riding comfort and vehicle controllability. Practice shows that these systems perform to a satisfactory degree only on good quality roads, as they have been designed specifically for the latter. This could be the cause of the more complicated car control and accidents on the lower-quality roads. Road ruts and local unevenness that impair car stability and traffic safety are not avoided even on the trunk roads. In this work, we investigated the conditions for directional stability, the influence of road and vehicle parameters on the directional stability of the vehicle, and developed recommendations for the road and vehicle control systems to combine to ensure traffic safety. We have developed a refined dynamic model of vehicle stability that evaluates the influence of tire tread and suspensions. The obtained results allow a more accurate assessment of the impact of the road roughness and vehicle suspension and body movements on vehicle stability and the development of recommendations for the safe movement down the road of known characteristics.

The dynamic process of the railway track–rolling stock interaction is characterized by time-dependent dynamics that are determined by both the varying characteristics of the interaction objects and the varying climatic conditions. This study investigated the effect of different groups of influence on the dynamic process, with a view towards the reduction of the cases of randomness during the registration of the process in experiments and an expansion of the understanding of the processes happening during the assessment of the registered data. The static nature of the rolling stock has been demonstrated to be not uniform and to influence the scattering of dynamic values under the variation of vertical and horizontal forces due to the characteristics of a rolling stock. The position of the rolling stock truck relative to the track axis during the movement of the rolling stock has been shown to enhance static non-uniformity. The results of the longitudinal force measurements under the three-point and Schlumpf methods have suggested that it is necessary to investigate the process of rail warping under the action of the rolling stock wheels. To enhance the output of the experiments, it is proposed to consider not only the stiffness of the basis of the oscillatory processes that imitate the physical process of oscillation of the system elements by means of the oscillation amplitude, but also the time of response to the oscillation process by using and assessing the triggering time rather than the frequencies of the oscillation processes.

This article presents an experimental–analytical statistical study of low-cycle fatigue to crack initiation and complete failure. The application of statistical and probability methods provides for the possibility of improving the characteristics related to the structural life and the justification for the respective values of cyclic loads in the design stage. Most studies investigating statistical descriptions of crack initiation or complete failure do not analyse the distribution of the characteristics, correlation relationships, and statistical parameters of low-cycle fatigue. Low-cycle failure may be quasistatic or (due to the fatigue) transient. Materials with contrasting cyclic properties were selected for the investigation: cyclically softening alloyed steel 15Cr2MoVA; cyclically stable structural steel C45; cyclically hardening aluminium alloy D16T1. All samples were produced in a single batch of each respective material to reduce the distribution of data. The lowest values of the variation coefficient of one of the key statistical indicators were obtained using the log-normal distribution, which is superior to the normal or Weibull distribution. Statistical analysis of the durability parameters showed that the distribution was smaller than the parameters of the distribution of the deformation diagram. The results obtained in the study enable the verification of durability and life of the structural elements of in-service facilities subjected to elastoplastic loading by assessing the distribution of characteristics of crack initiation and failure and low-cycle strain parameters as well as the permissible distribution limits.