We present results and special features of the conducted experimental studies into proposed theory of implementation of the coupled design of a center girder of hopper wagons for iron ore pellets. The importance and relevance of the set scientific and practical task is predetermined by economic expediency. In particular, by the attained possibility of bringing down the cost of manufacturing such wagons by10 %. In addition, such approach could be used for the modernization (including scheduled repairs of different types) of wagons under study, which would make it possible to significantly reduce the cost of their operation.The research found that the coupled design of the center girder of hopper wagons for iron ore pellets would guarantee to ensure the required indicators for operational reliability over the rated service life of wagon of 15 years. We can highlight as the scientific results of the work conducted the developed and experimentally-confirmed comprehensive technique for the implementation of coupled designs of wagon beams. The practical importance of research results is demonstrated by the proposed and patented solutions of technical realization of the chosen direction, implemented at a number of Ukrainian wagon building companies. The new and valuable results of present work include a created adequate spatial finite-element computer model of the improved design of hopper wagons for iron ore pellets.The proposed methodical complex for reducing the manufacturing cost of hopper wagons for iron ore pellets by the conjugated design of their carrying beams is expedient for application in other types of freight wagons, as well as other means of transport engineering

Energy saving direction on railway transport is substantiated based on reducing the motion resistance related to directing the undercarriages by a rail track. This motion resistance is defined as the kinematic resistance to motion. We clarified the nature of motion resistance associated with directing the rolling stock by a rail track. This opens up certain prospects in terms of reducing the kinematic motion resistance through design parameters of the trucks and the track. The kinematic resistance to motion could become an additional criterion for the optimal choice of characteristics of mechanical part of the undercarriages. The same applies to the permissible deviations in parameters of the rolling stock and the track.We model steady motion of a semi-wagon’s truck in a circular curve at constant velocity under the action of contact track forces, tractive force from the locomotive, and the unsuppressed centrifugal or centripetal forces of inertia. The kinematic motion resistance is determined as the longitudinal force applied to the truck’s pivot in order to balance all external forces.The dependences were obtained of specific kinematic resistance to motion on the motion velocity, base of the truck, radius of the curve, clearances of the wheelset in a rail track, and elevation of the outer rail. In particular, we derived a value of the motion velocity at which the minimum of resistance is observed. As we established, this speed does not match the equilibrium velocity and is 15−20 % lower.The study showed the possibility to predict resistance related to directing the undercarriages by a rail track. This opens up the prospect for choosing rational parameters of undercarriage gear of the rolling stock from the point of view of motion resistance

The study highlights the necessity to specify the safety factor against derailing of the wheels of a railway rolling stock. The modeling of the wheels’ derailment was carried out on the basis of considering the complete pattern of frictional interaction with the rails of the approaching and running-off wheels of a wheel pair. The simulation included the following previously overlooked factors: the dependence of the vertical component of the frictional force in the flange contact of the approaching wheel on the angle of the wheel running onto the rail; the influence of the frictional force in the flange contact of the approaching wheel on the increase in the horizontal lateral load on the flange; and the influence of the frictional force in the contact of the running-off wheel on the increase in the lateral load on the flange of the approaching wheel. The study has specified the safety factor – the Nadal criterion – against the derailment of the wheels of a railway stock. Unlike in the traditional approach, the safety factor of the wheel steadiness against derailment is assessed taking the frame force, rather than the lateral load on the flange, as the main factor of safety. This approach to determining the stability criterion gives more reliable results, since the frame force is more accessible for experimental and theoretical analysis.The proposed safety factor against the derailment of a railway stock, for different values of the flange inclination angle and the friction coefficient, is 10–50 % lower than the classical Nadal stability criterion. This makes the proposed criterion more reliable in assessing the safety of a railway rolling stock derailment

The analysis of operating conditions of traction drives of electric locomotives with asynchronous traction motors has been carried out. It was found that during operation in the output converter of an asynchronous motor, defects may occur, which leads to asymmetric modes of its operation. Models of a traction drive of an electric locomotive with asynchronous motors with scalar and vector control of the output converter are proposed, taking into account asymmetric operating modes. As a result of the simulation, the starting characteristics of the traction drive were obtained for various control methods both in normal and emergency modes of the drive. For the drive-in emergency mode, the following cases were investigated: the balance of the converter output voltages and the turn-to-turn circuit of 10% of phase A winding of the motor stator; imbalance of the output voltages of the inverter and an intact motor; imbalance of the output voltages of the converter and interturn short circuit of 10% of phase A winding of the motor stator. Comparison of the simulation results have shown that in emergency modes in the traction drive, the torque ripple on the motor shaft in the drive with vector control is 13% less, and in scalar control, the phase current unbalance coefficient is 22% less. The results of this work can be used to study the influence of the output converter control methods on the energy efficiency indicators of the traction drive of an AC electric locomotive.

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.