A review on design and testing methodologies of modern freight train draft gear system

Rolling stock connection systems are key to running longer and heavier trains as they provide both the connections of vehicles and the damping, providing the longitudinal suspension of the train. This paper focuses on the evolution of both connection and stiffness damping systems. Focus is on freight rolling stock, but passenger draw gears are also examined. It was found that connection systems have evolved from the buff and chain system used in the pioneer railways of the 1800s to the modern auto-coupler connection systems that are in-service worldwide today. Refined versions of the buff and chain coupling are, however, still in use in the EU, UK, South America and India. A wide range of auto-coupler systems are currently utilised, but the AAR coupler (Janney coupler) remains the most popular. A further variation that persists is the SA3 coupler (improved Wilson coupler) which is an alternative auto-coupler design used mainly throughout the former Soviet Union. Restricting the review to auto-coupler systems allowed the paper to focus on draft gears which revealed polymer, polymer-friction, steel spring-friction, hydraulic draft gears and sliding sill cushioning systems. Along with the single compressive draft gear units balanced and floating plate configurations are also presented. Typical draft gear acceptance standards are presented along with modelling that was included to aid in presentation of the functional characteristics of draft gears.

Analysis of technical solutions for a pallet car

Objective: Drawing on the results of the conducted marketing research, to work out a portrait of a potential consumer of groupage cargo transportation in a pallet wagon and a matrix of market consumer expectations with an assessment of customer focus and effective demand; provide a list of technical requirements for the car, potential routes, additional options and services for the transportation of groupage cargo in a pallet car, on the basis of which to evaluate possible options for technical solutions. Methods: Comparative analysis and assessment of the obtained analytical dependencies are applied; the need for options based on statistical processing of respondents’ answers is justified. Results: Technical solutions in several versions are recommended, the concept of a covered wagon with a large-volume body and an increased length of the loading and unloading front, with a draft gear, in a single-storey design, was proposed as a general one when a pallet car enters the market. An integral assessment of the opinions of respondents was carried out, by means of statistical analysis and visualization of the results obtained, a typical consumer was characterized. Practical importance: Marketing research data can be used when entering the market in terms of establishing optional lines of technical performance of rolling stock and its cost.

INFLUENCE OF DYNAMIC LOADING ON THE CHARACTERISTICS OF POLYMER IMPACT DAMPERS

The article is devoted to the study of the influence of dynamic loading on the characteristics of polymer elements of shock absorbers of the rolling stock of railways and to the description of the creation of a mathematical model of their work. The results of mathematical modeling are further used to solve problems of the longitudinal dynamics of rolling stock. In the study, the initial loading rate varied, the ambient temperature and the influence of the wear factor remained unchanged. For the operating speeds of a freight car, a mathematical model of the PMKP-110 draft gear was determined.

Dynamic Characteristics of Metro Trains under Rescue Conditions

In order to study the dynamic characteristics of metro train under rescue conditions, a detailed dynamic model with different train formations is established, taking into account the characteristics of wheel-rail contact, nonlinear characteristics of suspension components, and nonlinear hysteresis characteristics of the draft gear systems. To verify the accuracy of the simulation results, field tests are carried out and comparison is made between simulation and test results. Then, simulation analyses are conducted under the condition of AW0 rescues AW0, AW0 rescues AW3, and AW3 rescues AW3. Based on the simulation results, the longitudinal dynamic characteristics of the train under different rescue conditions are compared, and the influence of the longitudinal impulse on the dynamic performance of coupler and vehicle is analyzed. Finally, some suggestions are put forward to improve the draft gear as well as the rescue method.

Calculation of Loads on Carrying Structures of Articulated Circular-Tube Wagons Equipped with New Draft Gear Concepts

This article deals with the dynamic load and strength of the carrying structures of articulated circular-tube wagons. The study was conducted on the carrying structures of wagons equipped with new draft gear concepts. The accelerations on the carrying structures of wagons were determined using mathematical modeling. The results of modeling show that implementation of the draft gear concept can decrease the dynamic load of wagons by about 10% in comparison with that of a typical SA-3 coupler. Using the created computational models, the service life of the structure of the proposed articulated wagons was also determined. This research will encourage engineers to design modern structures of railway vehicles of higher operational efficiency.