DYNAMIC PERFORMANCE OF FREIGHT CARS ON BOGIES MODEL 18-1711

*LTD «Main Specialized Design Bureau of Car Building named after V. M. Bubnov (MSDBCB)», Mashinostroiteley Sq., 1, 87535, Mariupol, Ukraine, tel. +38 (0629) 51 86 43, e-mail n-mankevich@mail.ru Dep. «Wagons and Wagon Facilities», Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan, Lazaryan Str., 2, 49010, Dnipropetrovsk, Ukraine, tel. +38 (056) 776 84 98, e-mail sergeymyamlin@gmail.com


Introduction
Dynamic characteristics of the running parts of railway rolling stock directly affect the safe operation of trains in different modes of car loading and in the entire range of their motion speeds.That's why scientists and designers during improvement and construction of the new bogies of the rolling stock paid great attention to such junctions and elements the providing of necessary quality of the car course with the least resistance to its motion depends on [1,4,7,9,12].
Application of spring group in the construction of upgraded and new bogies with bilinear force characteristics and increased flexibility under the tare and gross rail load can improve the vertical dynamics parameters, promote traffic safety, as well as to provide the lesser sensitivity of the empty car dynamic parameters to the wedge wear.
In this case installation of the springs with increased altitude under the friction wedges allows one to create the necessary pressing force to provide both the better damping and increased resistance to the bogie side frames lozenging.
The use of non-metallic insertions between the friction wedges and bolster eliminates the «metal on metal» contact and stabilizes functioning of the shock absorbers [14].Increase of the friction wedges width or their form changing from the flat to the spatial one increases the side frames cohesion with the bogie bolster.It reduces the degree of the side frames lozenging and thus promotes the motion stabilization.Installation of the double-row tapered bearings, which do not require maintenance and repair on the wheel sets increases the overhaul life of the cars.Installation of elastic wear-proof insertions between the bearing adapter and supporting surface of the side frame axle-box nozzle protects the supporting and thrust surfaces of adapter and the side frame from the wearing.Thus the system of bogie primary suspension is created.The elastic insertion of adapter dampers the high frequency vertical oscillations and brings the wheel set back to its original position after oblique setting during motion in the curved track sections.This has a positive effect on the side frame durability [13,15].Installation of fixed contact bearings on the bolster provides an effective oscillation damping and reduces the wheel sets wearing.This significantly decreases the level of dynamic loading of the car center pivot and reduces the negative impact on the track [2,3,5,6,11,16].
A number of these design solutions are implemented in the new generation of bogies with an axle loading of 25 tnf, including the models 18-1711 (Table 1).

Purpose
The purpose of the article is the study of car dynamic qualities.According to the study results the use possibility of bogie model 18-1711 as the freight car running gears was evaluated.

Methodology
Running gears dynamic parameters of the rolling stock directly affect the motion safety parameters of the freight cars on the basis of wheel and rail interaction conditions.Experimental studies of car dynamic qualities are an important step in the modernization of existing bogie designs and in the construction of the new ones.Experimental data can confirm the results of theoretical studies and check the correctness of the design decisions.Therefore, the following algorithm can be determined as a research methodology: design engineering of the freight car bogie, theoretical research performing, experimental studies of freight car dynamic loading on the bogies of new construction in comparison with the serial ones, results analysis, and decision preparation about the possibility of using the bogies with new designs.

Findings
This paper presents the dynamic running tests of the tank car model 15-1900 and the  open car model equipped with bogies 18-1711, with an axle loading 25 tnf, which were carried out according to the papers [8,10].These types of cars are the most common types of the freight vehicle  During the tests the general working capacity of the vehicle in motion was examined.There were determined and evaluated the parameters of running characteristics of cars, which were equipped with bogie model 18-1711.The different motion speeds, including the speed exciding the design speed by 10% and different loading modes for the specific track sections with the corresponding construction and the current technical conditions were taken into account as well.
The technical characteristics of the studied cars are presented in the Table 2.The car length of the coupler pulling face, mm 12020 13920 The height of the car gravity center from the rail top level, mm -in the empty condition -in the loaded condition

Originality and Practical Value
The dynamic characteristics of freight cars with the bogie models 18-1711 are obtained.These characteristics give a complete idea of the car loading and allow us to estimate the dependency of the car dynamic performance on the bogie design.Two-axial bogie model 18-1711 with axle loading 25 tnf can be used as the freight cars running gears of the new generation of 1520 mm track.

Conclusions
1.The test results show that the studied cars have satisfactory dynamic qualities.
2. Maximum commonality of parts and components of their running gears and bodies with the previous generation of cars ensures their maintainability on the existing infrastructure of railways of the 1520 mm track.
3. To ensure the traffic safety during manufacturing and repairing of new generation cars, components and details, of which are unified with the previous generation of cars, it is necessary to exclude the possibility of "reverse installation", i.e. the installation of the new generation car parts with obsolete design.For this purpose there are many methods of control, such as logic control through the informationanalytical system of railway computer centers.
Ключові слова: динаміка вагона; динамічні випробування; осьове навантаження; уніфікація конструкцій; вагони нового покоління В. М. БУБНОВ 4 (46) РУХОМИЙ СКЛАД ЗАЛІЗНИЦЬ І ТЯГА ПОЇЗДІВ © V. M. Bubnov, S. V. Myamlin, N. B. Mankevych, 2013 on the track 1520 mm.The prototypes for these cars were respectively the tank car model 15-1547-03 and the 12-1704-04 open car model produced by PJSC «Azovobshchemash» for many years.Body researched cars also on most parts and components are unified with the previous generation cars.Bodies of the researched cars are also unified with the cars of previous generation according to the most parts and components.