Dynamic Stability of Cars in Long Freight Trains

1974 ◽  
Vol 96 (4) ◽  
pp. 1159-1167 ◽  
Author(s):  
F. B. Blader ◽  
E. F. Kurtz
Keyword(s):  
Simple Model ◽  
Linear Model ◽  
Dynamic Stability ◽  
Primary Effect ◽  
Lateral Stability ◽  
Transfer Matrices ◽  
Wheel Wear ◽  
Lateral Response ◽  
Natural Response ◽  
Freight Car

A method is described for investigating the lateral response and hunting tendency of cars in long trains. A linear model is developed representative of North American freight-car design with parameters descriptive of wheel wear and truck flexibility. Included is a simple model of the couplers assumed under tension. Transfer matrices are used to examine the behavior of groups of cars. Results are given showing that the behavior of a group of such cars under tension is no less stable than that of the single uncoupled car. The effects of variation in certain parameters on the natural response are described. Truck stiffness is shown to have a primary effect on the lateral stability of the car.

scholarly journals Reduction of freight car wheel wear of 1520 mm gauge railways

2020 ◽  
Vol 985 ◽  
pp. 012004
Author(s):  
V Ushkalov ◽  
T Mokriy ◽  
I Malysheva ◽  
L Lapina ◽  
S Pasichnik ◽  
...  
Keyword(s):  
Wheel Wear ◽  
Freight Car

Performance Analysis and Testing of a Conventional Three-Piece Freight Car Truck Retrofitted to Provide Axle Steering

1982 ◽  
Vol 104 (1) ◽  
pp. 93-99 ◽  
Author(s):  
P. Marcotte ◽  
W. N. Caldwell ◽  
H. A. List
Keyword(s):  
Steady State ◽  
Performance Analysis ◽  
Economic Impact ◽  
Dynamic Stability ◽  
Cast Steel ◽  
Performance Tests ◽  
Comparative Performance ◽  
Railway Operations ◽  
Freight Car ◽  
State Curve

The paper reviews the performance analysis and test work carried out on a conventional three-piece freight car truck retrofitted with elastomeric elements and cast steel steering arms in order to provide axle steering on curves and improved dynamic stability at higher speeds. A general approach on truck design is presented concerning linear truck dynamic stability and linear/nonlinear steady-state curve negotiation. Results of comparative performance tests are given, including the measurement of interaxle stiffnesses and the measurement of forces and angles of attack in curves, for both the conventional and the modified trucks. Comments are given on the economic impact that the retrofitted steering truck is expected to have on railway operations.

scholarly journals Modelling car motion and the calculation of the wear of wheels with the VNITsTT rolling surface profile

2019 ◽  
Vol 78 (1) ◽  
pp. 41-47
Author(s):  
A. M. Orlova ◽  
Yu. V. Savushkina ◽  
V. I. Fedorova
Keyword(s):  
Mathematical Modeling ◽  
Critical Speed ◽  
Surface Profile ◽  
Operating Conditions ◽  
Wheel Wear ◽  
Large Circle ◽  
Limit Values ◽  
Rolling Surface ◽  
Wheel Profile ◽  
Freight Car

The wear problem of wheels along rolling surface or thin flange is currently involved a large circle of specialists. There are opinions that it is necessary to establish new limit values for wheel wear in operation, put into practice the re-profiling (profile grin ding) of rails, install a larger number of floor-mounted lubricators in places of increased rail wear intensity, but one of the priority direction in this area is the development of a new surface rolling wheel profile for freight cars, the use of which will help to increase the turnaround time and increase the service life of the wheels in operation. Geometry of the rolling surface profile of the wheel should allow to provide a contact form between the wheel and the rail conformal or close to conformal. This solution has already found its application and achieved desired results on foreign railways (North America, South Africa, China, etc.). Authors developed a technique for designing a new wheel profile, which was used to build a profile of the rolling surface made by the Russian Research Center for Transport Technologies (LLC “VNITsTT”). As part of the study, calculations were carried out using the method of mathematical modeling of a freight car motion in the MEDYNA software package and performance indicators were evaluated on the VNITsTT rolling surface profile in comparison with the profile made according to GOST 10791 – 2011, and the wheel wear rate produced on the section of the track close to the average network operating conditions. Additionally, critical speed of the sinuous motion of the car was evaluated, which showed that despite the increased equivalent taper, the critical speed remained almost unchanged (an increase of 6 %). Theoretical calculation of the wheel resource based on the results of mathematical modeling has been made. According to the calculations, it was determined that the resource of the flange before turning for the RDCTT profile is 409.3 thousand km, and for the rolling surface — 663.3 thousand km, for the profile made according to GOST 10791 – 2011, the resource for the flange was 285.6 thousand km, and for the rolling surface 401.2 thousand km. Thus, the use of the VNITsTT profile is more effective than the profile made according to GOST 10791 – 2011 by 30.2 % for the flange and 39.5 % for the rolling surface. The developed VNITsTT profile, in comparison with the profile made by GOST 10791 – 2011, according to the results of calculations, confirmed the provision of standard indicators of the dynamic qualities of a freight car. 

Assessment of the wear of wheels of freight cars under the existing standards for releasing three-piece bogies with an axle load of 23,5 tf from repair

2021 ◽  
Vol 18 (1) ◽  
pp. 52-61
Author(s):  
A. V. Saidova ◽  
◽  
V. I. Fedorova ◽  
Yu. B. Zhitkov ◽  
I. V. Fedorov ◽  
...  
Keyword(s):  
Computer Modeling ◽  
Software Package ◽  
Practical Importance ◽  
Optimal Parameters ◽  
Wheel Wear ◽  
Rail System ◽  
Freight Car ◽  
Universal Mechanism

Objective: To assess the effect of the dimensions and tolerances of three-piece bogies of freight cars with a maximum static axle load of 23,5 tf when they are released from scheduled repair on the wheel flange wear in operation. Methods: For this purpose, drawing on a review and analysis of the literature in the field of wheel-rail system wear and the current requirements of guidelines for the repair of freight cars and their parts, design cases were formed to simulate a railway crew movement along a track of various designs with operating speeds, and the processes of wheel flange wear were studied using simulation computer modeling in the environment of the “Universal Mechanism” software package. Results: The parameters of freight car bogies which have the greatest impact on wheel wear have been determined. The quantitative values of the indicators of wheel wear for various cases of crew movement have been determined. The ways of reducing the wear of car wheels in operation by changing the dimensions and tolerances of bogies when they are released from scheduled types of repair are shown. Practical importance: The obtained results of the work commissioned by JSC “First Freight Company”are currently used to formulate requirements for the dimensions and tolerances of bogies when they are released from repair in order to establish the optimal parameters that would help to reduce the wheel flange wear in operation. In addition, they can be used in the developing new designs of freight car bogies.

Analysis of the effect of wheel–rail pair contact surface wear on the oscillations of a freight car with an increased axle load

2020 ◽  
Vol 2020 (4) ◽  
pp. 117-125
Author(s):  
V.F. Ushkalov ◽  
◽  
T.F. Mokrii ◽  
I.Yu. Malysheva ◽  
N.V. Bezrukavyi ◽  
...  
Keyword(s):  
Dynamic Stability ◽  
Life Extension ◽  
Rolling Stock ◽  
Wear Resistant ◽  
Profile Shape ◽  
Spatial Oscillations ◽  
Wheel Profile ◽  
Freight Car ◽  
Lateral Displacements ◽  
New Generation

At present, nearly all countries of the world develop and implement measures aimed to increase the competitiveness and efficiency of their railways. One of the priority lines is to increase the carrying capacity of freight trains. In Ukraine, 18-9817 trucks of axle load 25 tf were developed and adopted as basic ones for new-generation freight cars, and the ITM-73-03 wear-resistant wheel profile of flange thickness 32 mm was developed for them too. The aim of this paper is to study the effect of in-service variation in the wheel and rail profile shape on the spatial oscillations of a freight car with 18-9817 trucks and the ITM-73-03 wheel profile. The paper estimates the effect of in-service variation in the wheel and rail profile shape on the dynamic stability and ride performance of the car under consideration. The wear of wheels with the new profile is predicted by solving the geometrical problem of wheel–rail interaction with account for the mutual horizontal lateral displacements of the wheel and the rail, the wheelset angle of attack and angle of roll, the nonlinearity of the contacting surfaces, and the possibility of their conformal contact. The results of calculation of the spatial oscillations of the car in tangents and curves are presented. It is shown that wear-caused variation in the wheel and rail profile shape has little effect of the dynamic performance of a new-generation freight car with 18-9817 trucks with an increased axle load and the ITM-73-03 wear-resistant wheel profile, its dynamic stability and ride performance remaining at a high level. The use of the above car on the Ukrainian railways fully meets the objectives of home rolling stock renewal: vehicle ride performance improvement, running gear life extension, and vehicle and track wear reduction

Application of the semi-Hertzian method to the prediction of wheel wear in heavy haul freight car

Wear ◽  
2014 ◽  
Vol 314 (1-2) ◽  
pp. 104-110 ◽  
Author(s):  
Junjun Ding ◽  
Fu Li ◽  
Yunhua Huang ◽  
Shulei Sun ◽  
Lixia Zhang
Keyword(s):  
Wheel Wear ◽  
Heavy Haul ◽  
Freight Car

Tribological interrelationship of seasonal fluctuations of freight car wheel wear, contact fatigue shelling and composition brakeshoe consumption

Wear ◽  
1996 ◽  
Vol 191 (1-2) ◽  
pp. 210-218 ◽  
Author(s):  
J. Kalousek ◽  
E. Magel ◽  
J. Strasser ◽  
W.N. Caldwell ◽  
G. Kanevsky ◽  
...  
Keyword(s):  
Contact Fatigue ◽  
Seasonal Fluctuations ◽  
Wheel Wear ◽  
Freight Car

Influence of Car Tonnage and Wheel Adhesion on Rail and Wheel Wear: A Laboratory Study

1986 ◽  
Vol 108 (1) ◽  
pp. 48-58 ◽  
Author(s):  
S. Kumar ◽  
P. K. Krishnamoorthy ◽  
D. L. Prasanna Rao
Keyword(s):  
Wear Rate ◽  
Wheel Wear ◽  
Wheel Load ◽  
Adhesion Coefficient ◽  
Wear Rates ◽  
Bilinear Relation ◽  
Mild Wear ◽  
Rate Versus ◽  
Freight Car ◽  
Plastic Shakedown

This study presents the results and analysis of a laboratory investigation, of rail and wheel wear under clean and dry tangent track conditions, utilizing the IIT-GMEMD quarter scale simulation facility. Important factors influencing rail degradation are discussed followed by five different load/lubrication classifications of contacts. Influence of two important parameters, viz. wheel load (N) and adhesion coefficient of the tractive wheels (μ), on rail and wheel wear has been studied under conditions of Hertzian simulation. Seven separate experiments were conducted to measure wear of rail and nontractive freight car wheels. These were followed by six additional wear tests, simulating a typical U.S. locomotive, to investigate the effect of adhesion coefficients. The wear rates for tonnages* exceeding 65–70 t car increase at a much higher rate than those for tonnages below 65 t. Nonlinear relationship showing wear rate proportional to N5.4 and a bilinear relation have been developed. Considerations of contact plasticity show that the stress corresponding to 68-t freight load is a threshold stress which when exceeded leads to continual plasticity of new rails thus preventing shakedown. The influence of adhesion coefficient is also quite nonlinear, the wear rates being much higher for μ > 0.3. Photomicrographs of the surfaces of the wheel and rail at the end of the tests showed mild wear for μ ≤ 0.25 and severe wear for μ ≥ 0.35 indicating a transition of wear mechanism from mild to severe slightly above μ = 0.25. Wear rate is found to be approximately proportional to the square of the adhesion coefficient. A bilinear relation of wear rate versus μ, which is more accurate, is also given. It was observed that the effect of adhesion is more severe than the effect of tonnage alone. However, the tonnage effect is of serious consequence regarding plastic shakedown of the rails. A formulation of wear rate as a combined function of tonnage and adhesion coefficient is given. The urgent need for a solution of this problem is pointed out.

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