Rail Bars Research Articles

Dynamic behavior model of the ballastless railroad track segment considering wave processes

The paper is devoted to the modification of the dynamic behavior model of a flat orthotropic element under shock and vibrational impacts. The impacts were caused by solid cylindrical body for the case of ballastless railway construction. The suggested model allows simulating the element deformation in the upper structure of the ballast-free design track. The propagation of elastic waves moving with finite speeds, orthotropic properties of the foundation slab, which allow optimally selecting rod reinforcement are taken into account. The obtained analytical and graphical results make it possible to assess the influence of properties of the reinforced concrete slab, the underframe speed, the presence of defects in wheel sets or rail bars, as well as the characteristics of the technical content of the track section.

An Ag-loaded photoactive nano-metal organic framework as a promising biofilm treatment

Surface biofilm inhibition is still currently a considerable challenge. Among other organisms, Staphylococcus aureus is notable for its ability to form a strong biofilm with proved resistance to chemotherapy. Contamination of high-touch surfaces with S. aureus biofilm not only promotes disease spread but also generates tremendous health-associated costs. Therefore, development of new bactericidal and antiadhesive surface coatings is a priority. Considering that metal-organic frameworks (MOFs) have recently emerged as promising antibacterial agents, we originally report here the synthesis of a multi-active silver-containing nanoscaled MOF composite as a potential surface coating against S. aureus biofilm owing to a triple effect: intrinsic bactericide activity of the MOF, biocidal character of silver nanoparticles (AgNPs), and photoactivity after UVA irradiation. AgNPs were successfully entrapped within the benchmarked nanoscaled porous photoactive titanium(IV) aminoterephthalate MIL-125(Ti)NH2 using a simple and efficient impregnation-reduction method. After complete characterization of the composite thin film, its antibacterial and anti-adherent properties were fully evaluated. After UVA irradiation, the composite coating exhibited relevant bacterial inhibition and detachment, improved ligand-to-cluster charge transfer, and steady controlled delivery of Ag+. These promising results establish the potential of this composite as an active coating for biofilm treatment on high-touch surfaces (e.g., surgical devices, door knobs, and rail bars). Statement of SignificanceSurface contamination due to bacterial biofilm formation is still a demanding issue, as it causes severe disease spread. One possible solution is the development of antifouling and antibacterial surface coatings. In this work, we originally propose the use of photoactive metal-organic frameworks (MOFs) for biofilm treatment. The novelty of this work relies on the following: i) the treatment of strongly contaminated surfaces, as previous studies with MOFs have exclusively addressed biofilm prevention; ii) this pioneering work reports both antiadherent effect, which removes the biofilm, and bacterial inhibition; iii) our original successful strategy has never been proposed thus far, involving the multi-active combination of 1) intrinsic antibacterial effect of a photoactive titanium-based nanoMOF, 2) immobilization of biocide silver nanoparticles, and 3) improved anti-bioadherent effect upon irradiation of the composite coating.

Determination of the level of separate rail failure using the indicator of their reliability

During the operation, the upper railway track structure constantly tends to age, which includes the increasing number of failures. This process is controlled by the track maintenance system, which provides for the current maintenance of the track in a certain railway section. As part of the current maintenance of the track, in particular, works are performed to eliminate defective elements of the upper railway track structure, which appeared during functioning of the track structure. The dependence of the operational cargo turnover on the amount of transported cargoes has been analyzed. It is directly related to the issues of organization of maintenance of the railway track structure taking into account the current track operation conditions. Regression analysis of the reported data allowed establishing a mathematical model of the dependence of the value of operational cargo turnover on the value of the transported cargo. The service life of rails (rail bars) in the track section has been established to be related to the indicator separate rail failure during the period of operation of the upper railway track structure by defects. The safety level of rails (rail bars) can be determined based on the value of this indicator.

Formation of the stress-strain state of rail bars during welding with preliminary vertical bending

The article defines the parameters and working conditions for the final restoration of the integrity of the rail beams of a continuous gauge rail by electrocontact welding, as well as when welding rails with each other when they are elongated in the field by the method of preliminary bending. This involves the process of welding rails at temperatures above the temperature of their fixation. In this connection, an appropriate calculation scheme has been considered in relation to which the necessary parameters have been determined to ensure the conditions for straightening the residual curvature and, as a consequence, the formations of the corresponding stress state. To ensure the self-straightening conditions, the resulting formula for determining the residual bending arrow, the elimination of which under the influence of its own weight leads to the appearance of compressive stresses in the weld zone. In addition, a formula has been derived for determining the compressive stresses in the weld zone arising in the rail after the elimination of residual curvature. This means that when performing welding operations without forced straightening of the rails, you can restore not only their integrity, or weld them together. Thereby form a corresponding temperature-stress state.

Determination of the primary technical parameters of the test bench for controlling the temperature of rails and rail bars of continuous welded rail

One of the most important factors determining the reliability and safety of operation of the continuous welded rail track is the temperature of the rails. All conditions of laying, repair and maintenance of the track during the entire cycle of rails operation depend on it. The existing rail temperature monitoring method does not take into account a few significant factors and that leads to significant errors in determining the actual temperature of the rail bar. The authors propose a new rail temperature measurement method on a special test bench which maximally simulates possible environmental operating conditions for the rail bars, the profile of the roadway (embankment or cut), as well as the actual spatial latitude and meridian location of the rail slabs. At the bench, the studied rails are fastened with the help of rail braces on half ties, in the ballast bed, with sizes in accordance with the existing reference documents. At the first stage, the most common KB-65 intermediate fastener for the continuous welded rail in Ukraine will be used, while in subsequent stages KPP-5 fastening will be used.

Контроль температурно-напряженного состояния рельсовых плетей, выброса, разрыва и угона железнодорожного бесстыкового пути при помощи бализы

Контроль температурно-напряженного состояния рельсовых плетей, выброса, разрыва и угона железнодорожного бесстыкового пути при помощи бализы

Modeling of rail bar dynamic gap at its break for different stiffness values of rail base

Modeling of rail bar dynamic gap at its break for different stiffness values of rail base

Бализа как средство контроля температурно- напряженного состояния рельсовых плетей, прогнозирования выброса и разрыва плети

Бализа как средство контроля температурно- напряженного состояния рельсовых плетей, прогнозирования выброса и разрыва плети

Unacceptable use of bedrails.

Bedrails are designed to be used as safety devices but they are sometimes used as a form of restraint. In these circumstances their use can compromise dignity, autonomy and safety. Injuries have been caused by incorrectly fitted bedrails. They should be fitted so that the gap between the end of the bed and the headboard is less than 6cm or more than 25cm. Gaps between rail bars must be 12cm or less.

Modeling of Underground Cathodic Protection Stray Currents

Abstract OKAPPI, a numerical model for calculating cathodic protection (CP) problems involving underground pipelines, was extended to situations involving stray currents. Aboveground structures such as rail bars, power stations, electric train or tram vehicles, and overhead lifelines were integrated in the existing model in a straightforward and transparent way. As a result, it was shown that the model can be used to deal with most of the CP problems encountered with underground pipes. Situations where the sources of stray current, such as other CP installations or earthing systems located in the soil, were modeled and compared with theory. Cases involving the four standard kinds of CP interference (anodic, cathodic, combined, and induced) were calculated and discussed. A few complex situations involving overhead systems such as trams or railways were investigated. The theoretically expected phenomena were confirmed by the calculations.

Desgin and control studies of a linear synchronous motor for urban transit application

Magnetic circuit analysis is used for a design study of an iron-cored homopolar linear synchronous motor (LSM) for urban transit application. Using a suitable field or current angle, efficiency, power factor, and ratio of output power to total voltamps input are all calculated to be better than 85 percent. Other parameters including field or armature current, rail bar size, tooth or slot length, frequency, etc., are examined and found to be relatively insensitive. Control options are examined and field weakening, field or current angle control, or armature current control all appear to be feasible alternatives.