Influence of the Magnitude of the Working Stroke of the Constant

Contact Side Bearings of Freight Cars on the Parameters of the

Interaction of Rolling Stock and Track When Moving in Curved

Sections of the Track

Alexey Nikolaevich Davydov and Alexander Ivanovich Pribytkov

Ural State University of Railway Transport, Ekaterinburg, Russia

Keywords: Freight car, parameters of elastic side bearings, interaction of rolling stock and track, mathematical

modeling.

Abstract: This article is devoted to the study of the dynamic processes of the movement of a freight car along a curved

section of a railway track. Based on the developed simulation model of the movement of a freight car

equipped with constant contact side bearings, the influence of the working stroke of a constant contact side

bearing on the dynamic parameters of the interaction of rolling stock and track in curved sections of the

track is investigated. The paper presents the results of a study of the effect of the parameter under study on

the coefficient of the wheel's stability margin from rolling into the top of rail and shows that side bearings

with an increased working stroke of the elastic element are a more preferable design option compared to

side bearings with a standard working stroke according to the criterion of excluding complete side rolling of

the body to the side support, which leads to an improvement in the parameters interactions of wheel sets of

freight cars with rails when moving in curved sections of the track.

1 INTRODUCTION

To date, rail transport is the main component of the

transport system of the Russian Federation, which

ensures the functioning of the country's economy. In

this regard, the solution of issues to improve the

efficiency of its functioning is a very urgent task.

One of the ways to improve the efficiency of railway

transport is to improve the design of railway rolling

stock, aimed at improving the reliability of its

operation while reducing the economic costs

associated with its operation.

The modern development of computer

technology makes it possible to conduct research as

close as possible to the results of field experiments,

which significantly reduces the time and economic

costs when developing new design options for

various technical objects. This approach is widely

used in various industries, including transport

engineering.

To date, a separate direction has been formed in

the field of research on the dynamic processes of the

movement of rail carriages, called "dynamics of

wagons", within the framework of which theoretical

provisions have been developed to describe the

dynamic processes occurring during the movement

of wagons along both straight and curved sections of

the track. The application of these theoretical

provisions makes it possible to investigate the

impact of design improvement measures on the

expected changes in the running qualities of freight

cars. One of the directions in improving the design

of freight cars is the improvement of the connection

points of the body of the freight car with the running

gear, which are carried out in the form of

independent assembly units, which are called bogies.

An urgent problem in this area is the reduction of the

tendency of freight cars to tortuosity of movement in

straight and flat curves. The solution to this problem

is to equip the car with elastic constant contact side

bearings, which, due to the additional friction forces

arising between the car body and the bogie, make it

possible to effectively extinguish the tortuous

movement of the bogie under the car.

It should be noted that the constant contact side

bearings have found wide application in the design

of foreign and a number of domestic freight cars.

Side bearings of this type are mass-produced in

various modifications by several manufacturers and

the designs of bogies of freight cars of the largest

foreign manufacturers of running gear are adapted to

their use. However, to date, issues related to taking

Davydov, A. and Pribytkov, A.

Inﬂuence of the Magnitude of the Working Stroke of the Constant Contact Side Bearings of Freight Cars on the Parameters of the Interaction of Rolling Stock and Track When Moving in

Curved Sections of the Track.

DOI: 10.5220/0011584800003527

In Proceedings of the 1st International Scientiﬁc and Practical Conference on Transport: Logistics, Construction, Maintenance, Management (TLC2M 2022), pages 331-337

ISBN: 978-989-758-606-4

 2023 by SCITEPRESS – Science and Technology Publications, Lda. Under CC license (CC BY-NC-ND 4.0)

331

into account the peculiarities of domestic railway

transport, when adapting design variants of foreign

manufacturers for it, remain not fully investigated.

This article is devoted to one of such issues,

namely, the assessment of the influence of the value

of the working stroke parameter of the elastic

element of the side bearing on the dynamic

parameters of the interaction of rolling stock and

track in curved sections and the choice on their basis

of a rational value that provides the required

dynamic indicators of the movement of rail

carriages.

2 MATERIALS AND METHODS

To date, a significant number of scientific papers

have been devoted to the study of the movement of

railway rail carriages along curved sections of the

track, which affect a variety of research areas.

Among them, issues related to ensuring traffic safety

and improving the technical parameters of rail

crews, designed to reduce the loads acting on the

elements of rolling stock and railway track, occupy

one of the leading positions. Within the framework

of this direction, the issues of choosing rational

variants of the railway track design in curves are

considered (Akkerman, 2021; Akkerman, 2020;

Akkerman, 2020; Shkurnikov, 2020; Romanenko,

2020), as well as the issues of studying the influence

of rolling stock parameters on the dynamic

indicators of rolling stock movement (O'Donnell,

2005; Gabets, 2016; Wolf, 2005; Gadzhimetov,

2020; Davydov, 2021; Davydov, 2021; Tarmaev,

2019).

A significant part of the research in this area is

devoted to improving the running gear of freight

cars. One of the directions in this area is the

equipment of the car with constant contact side

bearings, which significantly reduce the tendency of

the bogie of the freight car to tortuous movement

and improve the parameters of interaction between

the rolling stock and the railway track. A significant

number of works by various scientists have been

devoted to the choice of the rational value of the

parameters of supports of this type.

However, to date, despite the research carried

out, not all issues in this direction are fully

investigated. One of such issues is the choice of the

magnitude of the working stroke of the elastic

element of the side bearing. At the same time, the

value of the working stroke is understood as the

maximum possible amount of compression of the

elastic element of the side pole, after compression to

which the side bearing becomes a solid with the

possibility of further compression only by the

amount of plastic deformation of the metal structural

elements of the bearing. The magnitude of the

working stroke is determined by the design of the

side bearing and, most often, is limited by the stop in

the design of the side bearing. The lack of research

in this area is largely due to the fact that the

magnitude of the working stroke of the side bearing

is laid by the manufacturer at the design stage of this

support and is limited by the design features of the

placement of the bearing between the body and the

bogie. However, many manufacturers have several

variants of the working stroke of side bearings,

which can be equipped with exactly the same bogies

of freight cars. In this connection, the development

of computational methods for studying the influence

of this parameter on the dynamic indicators of the

movement of freight cars in the curve and the

selection on their basis of rational values of the

values of the working stroke of the side bearing is an

urgent task aimed at improving the safety of train

traffic and increasing the efficiency of rolling stock

operation.

The main feature of the movement of freight cars

along curved sections of the track is the appearance

of centripetal acceleration, which occurs when

moving even at a constant speed. To neutralize the

centrifugal force in the curves, the out rail is laid

with some elevation relative to the inner one. The

centrifugal force acting towards the out rail of the

curve, due to the elevation of the out rail, can be

extinguished completely, partially or even

excessively (while the resulting force acts towards

the inner rail). In practice, for such cases, depending

on the degree of compensation of centrifugal force,

the concepts of sufficient, insufficient and excessive

elevation are used,

At the same time, it is obvious that a situation is

possible in which the elevation value will be

determined to a greater extent by the speed of

passenger trains and will be excessive for the

movement of freight trains. In this case, it is possible

to close the bearings from the inside of the curve,

which can lead to a redistribution of the load from

the weight of the car between the out and inner rails,

as well as to a change in the parameters of the

interaction of the rolling stock and the track.

Similarly, it is possible for a car to move along a

curve with a lack of elevation. In this case, it is

possible to side-roll the body to external bearings. At

the same time, it is obvious that a sufficiently large

amount of the working stroke of the bearing can

avoid the redistribution of the load between the

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nodes of the body support on the bogie, which in

turn will affect the change in the parameters of the

interaction of wheels with rails. Thus, in order to

choose a rational value of the working stroke of the

elastic element of the side support, it is necessary to

conduct studies of the influence of this value on the

movement parameters in the curved sections of the

path.

To date, in the practice of domestic and world

freight car building, two main schemes of load

transfer from the body to the chassis have been

formed. In the first case, the vertical and horizontal

loads from the body are transferred to the bolster of

the bogie through the central support (center bowl)

located on the bolster of the bogie (Fig. 1, a). To

limit the deviation of the body from the equilibrium

position, side poles (bearings) installed on the body

and their corresponding poles located on the bolster

of the bogie are used.

The second variant of load transfer (Fig. 1, b) is a

combination of a center bowl with elastic side

supports of continuous contact. In this case, the side

supports serve not only to limit the side rolling of

the car body, but also to transfer part of the vertical

load to the running gear, even when the latter is in a

state of stable equilibrium relative to the bolster. At

the same time, in the process of turning the bogie

relative to the body, friction forces arise between the

body bearings and the side poles, which leads to a

significant decrease in the tortuosity of the carriage

movement.

In the world practice of car building, two values

of the working stroke of the elastic element are used

– standard (Standard Travel) and increased (Long

Travel according to the terminology of MINER

Enterprises Inc. and Extended Travel according to

the terminology of A. Stucki Company (Davydov,

2013)). The standard stroke value for MINER

Enterprises Inc. products is 5/16” (0.0079 m), the

increased one is 5/8” (0.0159 m). For the variants of

bearings A. Stucki Company the standard stroke

value is 1/4” (0.00635 m), and the increased one is

5/8” (0.0159 m). At the same time, new models of

side bearings by these companies are developed and

produced exclusively with an increased working

stroke of the elastic element (5/8”).

To assess the influence of the magnitude of the

working stroke of the side bearing, an imitation

gondola car equipped with side bearings was

developed in the "Universal Mechanism" program.

The car model included 23 bodies connected by

mechanical connections. The total number of

degrees of freedom for all bodies of the mechanical

system was 134. The capabilities of the Universal

Mechanism program allow us to take into account

changes in the geometric and inertial parameters of

individual parts of the car, as well as the impact on

the movement of the car of vertical and horizontal

irregularities of the railway track both on straight

and curved sections of the railway track. This

software package has shown high reliability of the

results obtained and a number of studies have been

carried out with its application in the field of

modeling dynamic processes of interaction between

railway rolling stock and track.

When modeling, the parameter of vertical

rigidity of the elastic element of the side bearing was

assumed to be equal to 1.45 kN/m, which ensured

the transmission of 85% of the load from the body

weight through the side bearings. The value of the

working stroke was assumed to be equal to 0.0079

and 0.0159 m, with other parameters being equal.

The loaded mode of carriage movement was

simulated.

In order to isolate the influence of only

Figure 1: The scheme of supporting the body of a freight car on the running gear: a – through the center bowl; b – through

the center bowl and the constant contact side supports; 1 – the center bowl of the body; 2 – the bearing of the body; 3 – the

bearing of the bogie; 4 – the bolster; 5 – the center bowl of the bolster; 6 - the elastic side support of constant contact.

Inﬂuence of the Magnitude of the Working Stroke of the Constant Contact Side Bearings of Freight Cars on the Parameters of the Interaction

of Rolling Stock and Track When Moving in Curved Sections of the Track

333

the magnitude of the working stroke of the side

bearing, the mode of movement of the car along the

path without irregularities, both in the horizontal and

vertical planes, was studied.

The increase in the working stroke of the elastic

element of the side bearing is explained by the fact

that, compared with the standard value, it improves

the passage of curved sections of the track by the

car. In the situation under consideration, the car

body is side-rolled onto an external side bearing. At

the standard value of the working stroke, complete

compression of the elastic element of the bearing is

possible. In this case, significant forces of vertical

pressing of the support bearing against the body

bearing may occur, since their maximum value is

determined not by the rigidity of the elastic element

of the bearing, which is already compressed to the

maximum value, but by the values of the outstanding

horizontal accelerations acting on the body. At the

same time, there will be a redistribution of the

vertical load between the center bowl and the

compressed side bearing, towards an increase in the

load on the latter. All this will lead to an increase in

the moment of resistance to turning, compared with

what the side bearings should create and ultimately

worsen the car's fit into the curve. The increase in

the working stroke is designed to exclude the

possibility of complete compression of the side

bearing when the car passes the curved sections of

the track and thereby ensure the preservation of the

calculated values of the moment of resistance to the

bogie turning relative to the car body.

The study of the influence of the magnitude of

the working stroke of the side bearing on the

dynamic parameters of the movement of the car in

curves was carried out using a simulation model of

the movement of the rail carriage developed in the

software package "Universal Mechanism". This

software package has proven itself as a reliable and

effective tool for computer modeling of various

modes of movement of rolling stock.

For the possibility of studying various variants of

the structural design of the side supports of the body,

a generalized design scheme of the side support of

continuous contact has been developed (Figure 2).

The generalized scheme of the support (Figure 2,

a) includes the body of the support 1, fixed on the

bolster of the bogie and the cap of the support 2, on

the upper plane of which there is a contact surface

with the side bearing of the car body. An elastic-

dissipative element 3 is located between the housing

and the support cap.

The use of a parametric description made it

possible to model various variants of the structural

design of the body supports by setting the values of

parametric characteristics without the need to

change the structure of the model.

When studying the influence of paremeters of

side bearings on the running qualities of freight cars,

it is necessary to consider three modes of movement

of the car along the curve:

1. The movement of the car with a shortage of

elevation. In this mode of movement, the

magnitude of the centrifugal force is not fully

compensated by the gravity of the car due to

the inclination inside the curve and the

resulting force directed outward of the curve

acts on the body of the car

a) b)

Figure 2: Design scheme of the side support of the continuous contact of the body: a – the schematic diagram of the

support; b – the design scheme (projected onto the XCZ plane); 1 – the side bearing of the body; 2 – the cap of the side

support; 3 – the support body (mounted on the bolster of the bogie); 4 - the elastic-dissipative element.

TLC2M 2022 - INTERNATIONAL SCIENTIFIC AND PRACTICAL CONFERENCE TLC2M TRANSPORT: LOGISTICS,

CONSTRUCTION, MAINTENANCE, MANAGEMENT

334

2. Movement in an equilibrium position. In this

mode of movement, the magnitude of the

centrifugal force is fully compensated by the

gravity of the car due to the inclination inside

the curve and on the body of the car is in a

static equilibrium position.

3. The movement of the car with an excess of

elevation. In this mode of movement, the

magnitude of the projection of gravity on the

transverse axis of the car body turns out to be

greater than the magnitude of the centrifugal

force on the car body, the resulting force

directed inside the curve acts.

The occurrence of the considered modes of

movement is determined by the ratio of the

magnitude of the elevation of the out rail in the

curve and the speed of movement of the car along

the curve. The value of the elevation of the out rail

in the curve, which ensures the equilibrium mode of

movement of the car, is determined by the

expression (Verigo, 1986):

5,12=

where V is the speed of movement, km/h;

R is the radius of the curve, m

Within the framework of this work, the

movement of the car along a curve with a radius of

600 m was simulated. From expression (1), for the

given values of elevation and a given radius, the

corresponding values of the equilibrium velocity of

the carriage along the curve can be found.

To assess traffic safety under the conditions of

excluding the possibility of a wheelset derailment,

the wheel stability coefficient against derailment is

used in the work, which is determined by the

expression (Verigo, 1986):

tgβμ

μtgβ

⋅

+⋅

−

where

is the angle of inclination of the cone–

shaped surface of the wheel forming the ridge with

the horizon, rad.;

– coefficient of friction of the interacting

surfaces of wheels and rails;

is the vertical component of the reaction

forces of the oncoming wheel on the rails, H;

P is the horizontal component of the reaction

forces of the oncoming wheel on the rails, H.

When modeling, the parameter of vertical

rigidity of the elastic element of the side bearing was

assumed to be equal to 1.45 kN/m, which ensured

the transmission of 85% of the load from the body

weight through the side bearings, in accordance with

(GOST 9246-2013). The value of the working stroke

was assumed to be equal to 0.0079 and 0.0159 m,

with other parameters being equal. The loaded mode

of carriage movement was simulated. In order to

isolate the influence of only the magnitude of the

working stroke of the side support, the mode of

movement of the car along the path without

irregularities, both in horizontal and vertical planes,

was studied. Modes of movement with a deficit and

excess of elevation were studied. The mode of

movement with an equilibrium speed was not

considered in the framework of the study, because

there is no side rolling of the body, and

consequently, the deformation of elastic elements,

which is limited by the magnitude of the working

stroke, is not observed.

Figure 3: The amount of deformation of the elastic element of the side bearing when moving along a curve with a radius of

600 m, having an elevation of the out rail of 130 mm at a speed of 36 km/h, with a working stroke of 0.0079 m.

Inﬂuence of the Magnitude of the Working Stroke of the Constant Contact Side Bearings of Freight Cars on the Parameters of the Interaction

of Rolling Stock and Track When Moving in Curved Sections of the Track

335

3 RESULTS AND DISCUSSION

As a result of the experiments carried out, it was

found that for modes of movement with an excess of

elevation, in the case of the use of side supports with

a working stroke of 0.0079 m, it is possible to side-

roll the car body to internal bearings with their

complete closure. As an example, Figure 3 shows

the dependence of the deformation of the elastic

element of the side support to full compression,

consider the movement of the car along a curve with

a radius of 600 m, having an elevation of the out rail

130 mm at a speed of 36 km/h.

Figure 4 shows the change in the coefficient of

the wheel stability margin from rolling into the rail

head

From the graphs presented in Figures 3 and 4, it

can be seen that for the case of side rolling of the

body to internal bearings, a decrease in the value of

the stability margin coefficient is observed. This is

explained by the fact that the side rolling of the body

to the internal side bearings leads to a redistribution

of the vertical load between the wheel pairs and, as a

consequence, a change in the parameters of the

interaction of the wheels with the rails.

When studying the movement of a car equipped

with side bearings with an increased working stroke,

the closure of the sliders is not observed. However,

at the same time, there is the occurrence of lateral

vibrations, with a significant attenuation period,

which can be explained by the not sufficiently

satisfactory operation of friction dampers of bogie

vibrations at low speeds.

At the next stage of the work, a simulation of the

movement of a freight car with a lack of elevation

was carried out. In this case, similar observations

were obtained. For a car equipped with side bearings

with a working stroke of 0.0079 m, it is possible to

roll the car body to external bearings with their full

closure, while for a design variant with a working

stroke increased to 0.0159 m, the closure of the

bearings is not observed in the entire speed range

under study. At the same time, in the case of side

rolling of the body with full closure of the bearings,

there is a decrease in the value of the coefficient of

the wheel stability margin from rolling into the rail

head.

At the same time, it should be noted that in the

absence of closing of the side bearing with a full

choice of the working stroke, the parameters of the

interaction of wheel pairs and rails are identical for

both values of the working stroke, regardless of the

presence of a deficit or excess of elevation.

4 CONCLUSIONS

Summing up the research, we can make an

unambiguous conclusion that in the absence of a

complete side rolling of the body on the side

bearing, the parameters of the interaction of the

wheel pairs of freight cars with rails, when moving

in curved sections of the track, do not depend on the

magnitude of the working stroke of the elastic

element of the side support, but are determined

solely by the distribution of loads between the wheel

pairs, which, in turn, it is determined by the

distribution of loads between the side supports and

the bogie center bowl and largely depends on the

elastic-dissipative parameters of the elastic elements

of the side bearings. Thus, the choice of the

parameter of the working stroke of the side

support

should

made

according

the criterion of

Figure 4: Graph of the change in the coefficient of stability margin from rolling the outer wheel of the first wheelset onto

the rail head when moving along a curve with a radius of 600 m, having an elevation of the out rail of 130 mm at a speed of

36 km/ h, with a working stroke of 0.0079 m.

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the side rolling of the body to the side supports when

driving along curved sections of the track. At the

same time, the use of side bearings with an increased

working stroke avoids the complete side rolling of

the body to the side support, which leads to an

improvement in the parameters of the interaction of

wheel pairs of freight cars with rails when moving in

curved sections of the track and is more appropriate

compared to side bearings with a standard working

stroke of the elastic element.

The studies carried out clearly indicate that side

bearings with an increased working stroke have

advantages over side bearings with a standard

working stroke in terms of ensuring the best driving

qualities of a freight car in curves. At the same time,

this parameter is not decisive, due to the fact that it

only limits the maximum load at which the side

bearing is completely closed and which is

determined by the parameter of vertical stiffness of

the elastic element of the side bearing. It is quite

obvious that when choosing the parameters of the

side bearing, it is necessary to select the optimal

value of the vertical stiffness parameter based on the

results of experiments on the simulation model. At

the same time, as a test calculation, it is necessary to

check the selected parameters for the absence of

complete closure of the side bearings of the car body

and the bogie at a given value of the working stroke

of the side bearing and, if necessary, make its

adjustment of the working stroke in the direction of

increase. The application of this approach will allow

obtaining sufficiently accurate results and reduce the

time of experiments to determine the parameters of

side bearings.

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Inﬂuence of the Magnitude of the Working Stroke of the Constant Contact Side Bearings of Freight Cars on the Parameters of the Interaction

of Rolling Stock and Track When Moving in Curved Sections of the Track

337