Zbornik radova Koridor 10 - Kirilo Savić

annual tonnage in MT
3rd International Scientific and Professional Conference
CORRIDOR 10 - a sustainable way of integrations
Hard rails
Normal or
hard rails
Normal
rails
curve radius in m
FIGURE 15. Recommendations for use of steel grade in accordance with [8]
Maintenance policy (rail lubrication and grinding) has a significant impact on the service life of rails. It
is important to note that local parameters influence the development of wear and rolling contact fatigue
defects. Consequently, the rail infrastructure managers should adjust the maintenance policy to the
railway local parameters, including: curve radius, tonnage carried (daily or annual mega gross tonnage
- mgt) in the zone under consideration, the impact of falling and rising gradients, speed, cant on
curves, axle load and type of rolling stock.
Lubrication and grinding help combat the wear and rolling contact fatigue phenomena and applying
these maintenance methods appropriately can reduce costs maintenance.
Regularity and precision of application of a lubricant are of paramount importance. Account must be
taken of the influence of weather conditions (e.g. temperature, humidity) on the results of lubrication.
Use of a harder steel grade does not resolve the problem of lateral rail wear if the rail is not lubricated.
At best, the use of a harder steel grade may delay the lateral rail wear. In addition, the fact that
damaged metal is removed less rapidly may cause rolling contact fatigue to develop more quickly.
It is very important to detect rail defects in a track as early as possible. The defects due to rolling
contact fatigue can mask the ultrasonic signal during routine inspection and hence prevent the
detection of larger and deeper defects that may be present within the rail head, including any such
defects that may have developed from the shallower initial cracks. In praxis, it is important to combine
several detection methods in order to increase possibility of early detection of the defect: visual
inspection, optical testing method, ultrasound testing and eddy current testing.
The removal of severe defects in rail gauge corner and running surface entails extensive and
expensive rail maintenance (grinding). The appropriate grinding may prolongs rail service life by
preventing the emergence of defects or by delaying their development. Therefore, it is important to
apply the grinding strategies against HC defects as follows: preventive activities ("rail care"), corrective
activities (the removal of more or less severe defects), and cyclical (controlled) activities during the
whole rail service life.
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