Introduction. The paper considers the operation of interregional express trains operated by electric motor-car rolling stock whose route partly runs along non-electrified sections. These sections have electric trains hauled by a passenger diesel locomotive that also supplies electricity for the electric train auxiliary needs and the cabin microclimate system. The research is intended to compare the energy indicators of different modes of motor-car rolling stock operation on mixed routes with electrified and non-electrified sections.

Materials and methods. The paper analyses the actual operational consumption of fuel and energy resources for a number of electrified and non-electrified sections, including electricity supply for auxiliary needs of electric motor-car rolling stock and the cabin microclimate system. The paper compares the energy consumption of these sections for different series of tractive rolling stock.

Results. The author obtained data on the fuel consumption of a diesel locomotive with an electric train and a diesel train depending on the train composition and time of year, as well as indicators of specific fuel consumption for a diesel locomotive driving an electric train and a diesel train in negative temperature zones, i. e. with operating heating.

Discussion and conclusion. The study shows that a diesel locomotive for electric train traction is less feasible than a diesel train in terms of energy consumption. The author gives a preliminary assessment of comparative characteristics of energy consumption under different modes of motor-car rolling stock operation on non-electrified sections. If these research data remain relevant, the next stage should include data processing from on-board registration systems and comparative testing.

Introduction. Solving the dynamics problems of rail cabs requires specifying the kinematic disturbance of their oscillations represented through equivalent vertical and horizontal geometric irregularities of the left and right rails. The formation of such four-dimensional disturbance involves the generation of multivariate random processes based on auto- and cross-correlation functions or spectral and cross-spectral densities of actual recordings of rail track irregularities. The paper refines the probabilistic properties of the disturbances that cause rail cab oscillations and develops a new simplified method for their generation.

Materials and methods. The paper provides a probabilistic analysis of long-term (over 14 km) recorded natural rail track irregularities and an approximation of the obtained probabilistic properties with analytical expressions corresponding to differentiable random processes. The parameters of these processes were found by the least-square method. The new method generated random irregularities for the track coordinate using a multivariate shaping filter whose impulse characteristics were found with analytical expressions of auto- and cross-correlation functions.

Results. The authors refined the probabilistic values of rail track irregularities that may be used to specify disturbances of rail cab oscillations when solving dynamics problems and proposed a simplified irregularity generation method for the track coordinate argument that provides high convergence to the previously obtained data.

Discussion and conclusion. The received probabilistic characteristics may be applied to generate a multivariate random irregularities when examining the oscillations of different type rail cabs occurring at different speeds movement. The proposed simplified generation method reduces the time for simulating disturbances.

Introduction. In order to increase the cold downtime of diesel locomotives in winter, the authors suggest using thermal accumulators in the oil system. The research considers using thermal accumulators to increase the temperature of the pumped oil portion immediately before starting the diesel motor in negative ambient temperatures.

Materials and methods. The research covers a thermal accumulator suggested for use as part of the diesel motor oil system. The researchers conducted a physical laboratory experiment on a reduced copy of the accumulator and scaled the results to a diesel shunter based on the similarity theory. The temperature parameters were recorded in real time using a microcontroller-based automated measurement system. Microsoft Excel was used for a statistical analysis of the experimental results.

Results. The tests results of the laboratory sample of the thermal accumulator for motor oil are presented. The authors evaluated the dependencies of the oil temperature inside the thermal accumulator and inside the crankcase of the shunter diesel motor on the cold downtime, which proves the effectiveness of the proposed technical solutions.

Discussion and conclusion. Accumulation of thermal energy of locomotive diesel motors service fluids is a promising method increasing the diesel locomotive pre-launch performance in negative temperatures. The heat preservation method used in the thermal accumulator is versatile and may be applied to both oil and cooling liquid of transport diesel motors. The authors propose to use thermal accumulators on diesel shunters.

Introduction. Railway transport has ultrasonic control as one of the main methods of detection of defects of the type of continuity violation (cracks, pores and others) both in the base metal and in weld seams of various items. Ultrasonic control tools primarily include a flaw detector with piezoelectric transducers. Piezoelectric transducers are usually supplied with the flaw detector depending on the general or specialized configuration. Flaw detector manufacturers often offer the customer their own piezoelectric transducer kits for certain device configurations with installed software referring to incompatibility of other manufacturers piezoelectric transducers with the electronic unit. The article is intended to carry out a comparative analysis of ultrasonic control sensitivity using straight and angle transducers of different manufacturers, and to compare the results with the control sensitivity using piezoelectric transducers traditionally used on the railways.

Materials and methods. The paper gives the results of testing the sample using Flaw Detector UD2-102 Peleng produced by Altek LLC. Industrial oil I-20 was used as a contact fluid. The authors compared the following piezoelectric transducers: straight (made by Altek LLC and NPO INAKON (Russia)) and angle (Altek LLC (Russia), Iskatel-2 LLC (Russia) and SIUI (China)).

Results. The paper reports the results of an experiment detecting artificial reflectors in the form of through cylindrical side holes in a sample of 20GL steel by straight and angle piezoelectric transducers of different manufacturers using Flaw Detector UD2-102 Peleng.

Discussion and conclusion. Connection of other manufacturers transducers to Flaw Detector UD2-102 Peleng of Altek LLC confirmed that they are compatible with the electronic unit. Thus, given the choice of a wide selection of piezoelectric converters from various manufacturers, the requirement of coordination with the electronic unit of Flaw Detector UD2-102 may be neglected. At the same time, it is important that the manufacturer stipulates the joint use of its product with other types of flaw detectors.

Introduction. The design of the longitudinal side of the gravity humps provides for the implementation of structural and technological calculations, which simulate the rolling of the cut of single cars with established characteristics —“calculated runners”. The fleet of cars has been significantly updated, the share of cars with an axle load of 25 t has increased, and the innovative cars models with an axle load of 27 t has been constructed since the development of the gravity humps design standards. The object of research in this work is the numerical characteristics of the main specific resistance to movement of cars when rolling down a gravity hump. The subject of the study are the values of the main specific resistance to movement of “calculated runners” for modern car fleet circulation on the Russian railway network. The purpose of the study is to update the parameters of the main specific resistance to movement of “calculated runners” used in the design of a gravity hump.

Materials and methods. The researchers made in-field observations of single cars rolling down a real gravity hump. The observations were made on a straight track section without braking within the measurement area in summer. The statistical analysis of single cars rolling on the same gravity hump in summer involved a computer vision system developed by the Rostov Branch of the Research and Design Institute for Information Technology, Signalling and Telecomminucations in Railway Transportation.

Results. The authors obtained new values of the main specific resistance to movement for the established types of “calculated runners”, which have significantly decreased compared to existing standards. The use of new characteristics of “calculated runners” would improve the quality of gravity humps calculations in the development of design solutions for height, longitudinal side and technical equipment of gravity humps.

Discussion and conclusion. The obtained results showed the need to adjust the rules and design standards of shunting facilities in terms of determining the values of the main specific resistance to movement for the established types of “calculated runners”. In order to introduce new values of the main specific resistance to movement into regulatory documents, it is advisable to continue research in order to expand the sample size and clarify the obtained results. At the same time, similar studies should be performed at different marshalling yards of the network located in different climatic zones.

Introduction. Interference in the continuous automatic cab signalling channel distorts transmitted signals and causes signalling malfunctions. Reduction of interference in the channel involved a previously proposed receiver with quadrature channels and its implementations with non-linear signal transformation in one or two sections of the receiver. The research is intended to find the best implementations of the quadrature receiver.

Materials and methods. The research uses a computer simulation of the operation of the studied receivers under the influence of harmonic interference from a power line. For this purpose, the authors used Simulink visual programming environment and developed receiver simulations, applied the harmonic interference simulation model and conducted experiments to assess noise immunity expressed as a time interval showing receiver malfunction.

Results. The researchers determined the effect of non-linear signal transformation on the harmonic noise immunity of the receivers.

Discussion and conclusion. The research shows that the receiver with a deadband is the most preferable of all considered variants of quadrature receivers in terms of maximum harmonic noise immunity. The receiver with combined interference suppressor and deadband is slightly inferior.

Introduction. Solutions to car weight-bearing capacity problems currently tend to benefit from the properties of aluminium alloys. Aluminium alloy wagon units are about three times lighter than steel ones, which helps to carry more freight with the same number of cars while maintaining the specified axle load. The Ural Wagon Factory was the first to use aluminium as a structural material for the manufacture of axle box mount in the 1950s.

Materials and methods. This paper reviews the research on the production of wagon wheel pair axle boxes from aluminium alloys in Russia and abroad. It examines the manufacturing techniques of the aluminium axle box and the results of bench and operational tests.

Results. The analysis of production technologies of aluminium alloy axle boxes and the results of operational tests of the pilot batch of axle boxes revealed the advantages and disadvantages of this design and led to the conclusions about its feasibility.

Discussion and conclusion. The authors propose to resume the use of aluminium alloys in wagon axle boxes considering modern operating conditions. Confirmation of its technical and economic efficiency requires a set of bench and operational tests with the use of modern diagnostic tools.