scholarly journals Measurements Result Analysis of Deformation Characteristics of Transition Zones on the Modernized Line Púchov – Považská Teplá

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Libor Ižvolt ◽  
Peter Dobeš

Abstract The current trend in Europe and worldwide is to support the development of so-called green transport, characterized by lower energy consumption and lower CO2 emissions. Rail transport meets these conditions and therefore considerable funding is being spent not only on the construction of high-speed lines but also on the modernization of existing railways, especially those forming part of the trans-European corridors. Three corridors of the basic TEN-T network pass through the territory of the Slovak Republic. In the Žilina Region, there are two corridors, Balt – Adriatic and Rhine – Danube, with a common section Púchov – Žilina, which is currently being modernized. It is a known fact that railway lines often show a greater degree of degradation in the transition zones between the earthwork and the structures of sub-ballast layers. Since every railway infrastructure management aims to minimize maintenance costs, while ensuring the safety and comfort of passengers, it is necessary to pay increased attention also to transiton zones. In this context, the presented paper deals with the analysis of values of deformation characteristics on the modernized line section Púchov – Považská Teplá, which is characterized by several bridge structures and tunnels. The values were obtained within the quality inspection of work in transition zones located between the earthwork and the structures of sub-ballast layers.

2020 ◽  
Vol 64 (188) ◽  
pp. 149-160
Author(s):  
Janusz Poliński

Technical diagnostics is an integral part of the railway maintenance process. Through timely maintenance, in addition to ensuring the safety, functional and technical reliability of the infrastructure, maintenance costs are reduced and downtime losses, due to failures or premature repair requests, are eliminated or reduced. The track infrastructure diagnostic tools have evolved. This is related to, among others, the miniaturisation of instruments, reading accuracy during motion, as well as upgraded measurement automation and result analysis. Currently, data obtained from multifunctional diagnostic tools is the basis for the developed Russian railway infrastructure maintenance and operation digital model. The strategic development of mobile diagnostic labs is the gradual transition to solutions with advanced digital analysis, supported by artificial intelligence, monitoring and forecasting. The article presents the development of mobile labs for the railroad infrastructure condition diagnosis up to the current solutions, in which measurements take place without human intervention and the obtained information is transmitted in real time to the analysis and decision centres. Keywords: rail transport, measuring wagons, digitisation of railways, Russian railways


1971 ◽  
Vol 55 (1) ◽  
pp. 13-38 ◽  
Author(s):  
C. J. PENNYCUICK

1. Glide-comparison measurements were made on ten species of East African soaring birds using a Schleicher ASK-14 powered sailplane. Horizontal and vertical speed differences between bird and glider were measured by a photographic method, and used to estimate the bird's horizontal and vertical speeds relative to the air. The analysis refers to the white-backed vulture, since by far the largest number of measurements was obtained on this species. 2. A regression analysis using a two-term approximation to the glide polar yielded an implausibly high estimate of induced drag, which was attributed to a lack of observations at lift coefficients above 0.72. An amended glide polar was constructed assuming elliptical lift distribution and a maximum lift coefficient of 1.6 to define the low-speed end, while the high-speed end was made to pass through the mean horizontal and sinking speeds of all the experimental points. This curve gave a minimum sinking speed of 0.76 m/s at a forward speed of 10 m/s, and a best glide ratio of 15.3:1 at 13 m/s. It did not differ significantly (in the statistical sense) from the original regression curve. 3. In comparing the estimated circling performance, based on the amended glide polar, with that of the ASK-14, it was concluded that the rates of sink of both should be comparable, but that the glider would require thermals with radii about 4.3 times as great as those needed to sustain the birds. The conclusions are consistent with experience of soaring in company with birds. 4. In an attempt to assess the adaptive significance of the low-aspect-ratio wings of birds specializing in thermal soaring, the white-backed vulture's circling performance was compared with that of an ‘albatross-shaped vulture’, an imaginary creature having the same mass as a white-backed vulture, combined with the body proportions of a wandering albatross. It appears that the real white-back would be at an advantage when trying to remain airborne in thermals with radii between 14 and 17 m, but that the albatross-shaped vulture would climb faster in all wider thermals; on account of its much better maximum glide ratio, it should also achieve higher cross-country speeds. It is concluded that the wing shape seen in vultures and storks is not an adaptation to thermal soaring as such, but is more probably a compromise dictated by take-off and landing requirements. 5. The doubts recently expressed by Tucker & Parrott (1970) about the results and conclusions of Raspet (1950a, b; 1960) are re-inforced by the present experience.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Liudmyla Trykoz ◽  
Svetlana Kamchatnaya ◽  
Dmytro Borodin ◽  
Armen Atynian ◽  
Roman Tkachenko

Purpose The purpose of this paper is to develop a technological method of protection against electrical corrosion. One more way to protect the objects is to prevent the electrical current from getting to them. For example, railway objects are surrounded with a material with raised electrical resistance. Design/methodology/approach The railway infrastructure objects (foundations, contact-line supports, reinforced concrete sub-bases, bridge structures, pipelines of engineering networks, supports of passenger platforms and pedestrian bridges, concrete plinth walls of station buildings) are subjected to destruction due to the action of electrical current. One of destruction factors is a corrosion of the concrete constructions which is caused by the leakage current action. Findings Leakage currents and stray currents bypass the structure of supports of high passenger platforms or pipes of engineering networks. These currents spread by the line with the least resistance outside of the structures. Research limitations/implications Electrical leakage current from the rails gets into such structures through sleepers, ballast and soil and leads to accelerated corrosion leaching of concrete. Practical implications The constructions are protected against the destructive effect of electrical corrosion on the metal or concrete of the structure. This scheme is suitable for the construction and reconstruction of railway structures which operate on electrified sections of railways. Originality/value Schemes of technological solution are proposed for protection of foundations, supports of high passenger platforms, pipelines of engineering networks, etc. For this, the arrangement of soil-contained screens with big electrical resistance is suggested.


Author(s):  
Dilong Guo ◽  
Wen Liu ◽  
Junhao Song ◽  
Ye Zhang ◽  
Guowei Yang

The aerodynamic force acting on the pantograph by the airflow is obviously unsteady and has a certain vibration frequency and amplitude, while the high-speed train passes through the tunnel. In addition to the unsteady behavior in the open-air operation, the compressive and expansion waves in the tunnel will be generated due to the influence of the blocking ratio. The propagation of the compression and expansion waves in the tunnel will affect the pantograph pressure distribution and cause the pantograph stress state to change significantly, which affects the current characteristics of the pantograph. In this paper, the aerodynamic force of the pantograph is studied with the method of the IDDES combined with overset grid technique when high speed train passes through the tunnel. The results show that the aerodynamic force of the pantograph is subjected to violent oscillations when the pantograph passes through the tunnel, especially at the entrance of the tunnel, the exit of the tunnel and the expansion wave passing through the pantograph. The changes of the pantograph aerodynamic force can reach a maximum amplitude of 106%. When high-speed trains pass through tunnels at different speeds, the aerodynamic coefficients of the pantographs are roughly the same.


2011 ◽  
Vol 280 ◽  
pp. 186-190
Author(s):  
Shou Tan Song ◽  
Ji Wen Zhang ◽  
Xin Yuan

The dynamic performance of continuous girder under the train in a series of speed is studied through examples, and the main conclusions are given in the following. The resonance mechanism of continuous girder is similar to simply supported beam. The vehicle wheel load forms regular moving load series, which induces periodical action and resonance of the bridge. The damping ratio of bridge itself has less effect on the amplitude at the loading stage, but significant effects appear when the load departs from the bridge. The count of continuous spans also has less impact on the dynamic coefficients, so three continuous spans can be adopted for calculation and analysis. Span and fundamental frequency have significant influence on dynamic coefficients of bridge structures. To extend the span of the bridge structure can reduce the dynamic coefficient while keeping its frequency invariant. The fundamental frequencies of different bridges are corresponding to certain resonant speeds, which calls for the attention in the design.


2019 ◽  
Vol 5 (3) ◽  
pp. 36-44
Author(s):  
Viktor A. Bogachev ◽  
Yuri A. Terentyev ◽  
Viktor V. Koledov ◽  
Taras V. Bogachev

Background: Research is ongoing relating to the analysis of a set of issues that arise in connection with the creation of the operating on the basis of vacuum magnetic technologies a transcontinental high-speed land transport corridor, connecting the eastern regions of China with Russia. As part of the variation calculus task, the geopolitical, economic, social, logistic, geographic, geomorphological, seismological, topographic components of the project are considered, in which it is assumed that the high speed overland route will pass through the north-western part of the historical region of Dzungaria. Aim: Find the most optimal from the point of view of the above components the location of the most important section of high speed overland route passing through Central Asia. Methods: Variational methods for solving an optimization problem with the use of a computer math system. Results: After creating a fairly informative and versatile picture of the region in question, the foundations of the corresponding mathematical models are built. Conclusion: The New Dzungarian Gates is a key element in choosing the location of a high-speed overland route based on VMLT.


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