Methods for reducing the wear of wheeled pairs

1. METHODS FOR REDUCING
THE WEAR OF WHEELED
PAIRS OF ROLLING STOCK
Has prepared by Bakyt U

2. Introduction
◦ The increase in rail transport in recent decades has complicated the operating conditions of the
track and rolling stock, and caused faster wear of rails and wheel pairs. Whereas in the past there
was intensive wear on rails and wheels on mountain passes with long rises and slopes, in recent
years it has also become common on lowland railways. The intensity of wear of rails and wheels
of rolling stock is influenced by many factors: imperfection of spring suspension; difference of
diameters of surfaces of rolling surfaces of one wheel pair; asymmetry of wheel pairs when
placed in the frame of the truck; static weighing of wheelsets and increase of train mass.
According to many experts, the main role in the process of increasing bandage wear was played
by the completion of the conversion of the operational car fleet to rolling bearings and the change
of the gauge from 1524 to 1520 mm. In the first case, the ridges of the wheel pairs and the rails
became dry-friction due to the cessation of the flow of liquid lubricant from the sliding bearings
into the contact zone. In the second case, the wheel pairs will change to the ridges of the rolling
stock when the rail distance decreases.

3. Review of ways to reduce the wear of wheeled pairs of
rolling stock
◦ Main faults of wheel pairs bandages: parametric failures (marginal rolled, comb wear
in thickness); violation of rolling stock repair technology, errors in train driving
(formation of sliders, shear of the brace relative to the wheel center, uneven wear of the
rolling surface); violation of bandage manufacturing technology and formation of
wheel pairs (formation of sinks, cracks, loosening of the brace).
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4. Manual and automated methods are used to measure the
wear intensity of rolled and comb wheels. For manual
measurement, an absolute template is used.
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5. ◦ The absolute template measure the roll, slider,
bulk and thickness of the comb. The rental is
carried out in a skating circle located 70 mm
from the inside edge of the wheel. When
measuring the depth of rolled risks 3 and 4
should coincide. Having lowered the support
brace 2 to the top of the ridge, it is necessary to
press the vertical face of the template and the
foot to the inner face of the rim of the wheel.
Determine the distribution of the scale on the
engine 5 versus risks 7 on the leg 6. Slider and
naver (metal offset on the rolling surface (not
more than 0.5 mm)) are found on the
difference of readings at the site of the defect
and in an unmarked place. If the defect is
offset against the wheel rolling circle, engine 5
shall be adjusted before measurement.
◦ It has now been possible to reduce the
wear to 500-700,000 km. of the
rolling stock. In 85% of cases, the
wear of the edge of the brace has a
higher intensity than the wear of the
skiing surface [1]. To increase the
service life of wheel pairs of rolling
stock use surface reinforcement,
profile optimization and
tribomechanical materials. Consider
in detail each method of reducing the
wear of the rims of wheelsets.
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6. Wheel lubrication of rolling stock
◦ The use of a lubricant can change the friction properties of the third body, resulting in a
lower friction coefficient and reduced wear. Lubrication of wheel combs and the side
surface of rails to reduce wear intensity has been actively used on Russian railways
since the middle of the XX century. Distinguish the side surface treatment with mobile
rails and lubrication on combs Wheel pairs with mobile and on-board lubrication
systems. Currently, the wheel-rail is widely used in contact various lubricants. They are
divided in terms of their aggregate state for liquid (oils), plastic and solid. Liquid
lubricants require increased sealing of lubrication systems to prevent leakage and
contamination of the traction surface of the wheel and the upper track. Prospective
lubricants are solid and plastic, free from the above shortcomings.
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7. Development of production process of creation of
tribomechanical materials
◦ In order to study in depth the abrasion process, as well as to develop new
tribomechanical materials that meet modern conditions of operation of rolling stock,
the WGPS has developed a production complex for the creation of tribomechanical
materials. The objects of the study are friction modifiers RAPE,
◦ used in rail transport for lubrication of wheel ridges of rolling stock. The production
process consists of two technological steps: development and testing of
tribomechanical materials. For the development of tribomechanical materials, a
laboratory complex (fig. 4) is used, including an experimental laboratory installation
(fig. 4, a) and a fundamentally new bench analogy simulating the process of abrasion
of solid tribomechanical materials (fig. 4, b)
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◦ The introduction of the laboratory complex ensures a minimum of time, ease of
measurement, possibility of changing various parameters that do not require operation of
the measuring rolling stock. These costs are significantly lower than for field trials. The
test apparatus (Fig. 4, a) consists of a tube 1 in which the tribomechanical material in the
form of a rod and a base 2. The apparatus is mounted on a caliper 4, rotating the rotor
1M61M and simulates the process of abrasion of the developed material about the model
wheel 3 rolling stock. During the test process, the feed angle of the material to be
developed, the load, the rotation speed of the Wheel 3 model can be specified to
determine the possible service life. During the formation of the layer, the interaction of
the material with the wheel model is removed from the wheel rail brush.

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◦ Analogy simulating the process of abrasion of the membranes of tribomechanical
materials about the crest of the wheel rolling stock, is successfully modelled in
laboratory conditions on friction machines such as «Amsler» (fig. 4, b). The top shaft of
the friction machine type «Amsler» is fixed with the holder with the shell of the
lubricating element, and the bottom - roller, similar length and material of wheel comb.
The instrumentation system is capable of recording: Change in friction torque; Change in
contact temperature; Roller speed; Linear wear of the casing during testing; Low load
(up to 15 N) on the coating of the lubricant. Due to this analogy, it is possible to
determine the influence of load, speed, temperature, as well as material and thickness of
the shell on the process abrasion and consumption of liner materials. This will optimize
the comb-ray examination process by applying a minimum amount of tribomechanical
materials, while reducing the wear of the wheel crests of rolling stock.

12. Conclusion
◦ Based on a review of the existing modern methods of reducing the wear
intensity of the wheels of rolling stock, it has been determined that at present
there is no universal method. Each method is effective under certain conditions
of repair, maintenance and operation. However, the use of several methods at
the enterprises Joint-Stock Company National Company Kazakhstan Railway
with the right approach can give the necessary economic and tribotechnical
effect.
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