EVALUATION OF INNER SHEAR RESISTANCE OF LAYERS FROM MINERAL GRANULAR MATERIALS

The methodologies used to assess the inner shear resistance of granular layers from minerals measured in the laboratory with and without geosynthetic reinforcing layers are described in this paper. For the measurements, a multi-level shear box is applied without considering vertical loads on the top layer. In the literature and engineering practice, an accepted calculation method for determining inner shear resistance exists. It is the shear force with linear shearing speed, primarily after a peak force value. This can be accounted for in the present case by calculating the average force value for the 40-80 mm shear range using previous scientific and research achievements. The article details each possible additional method and compares it different methods. Three granular materials, as well as six planar geosynthetics, were studied. For this purpose, the results of 216 measurements were considered and processed using 61 different shear function-qualification parameters. The calculations were performed using a simplified function fitting test and a selection process to maximize the allowable relative standard deviations. All three types of materials and four classification parameters were chosen as references for comparability. As a result, only one alternative parameter can be used to determine the reinforcing-weakening values with a maximum deviation of 5% while not producing insufficient results in the placement (ranking) of the individual granular material and geosynthetic pairings. This parameter is the area under the function (integral) calculated on the measurement graph of the 40-80 mm shear range, in kN×mm unit; it gives correct values only if the reference granular material is the considered railway ballast, the shearing plane is the geosynthetic's plane (i.e., the so-called "0‑plane"), and the reference qualification parameter is the original recommended parameter. The best relative standard deviation values were 20% and 30%

DETECTION PROCESS OF ENERGY LOSS IN ELECTRIC RAILWAY VEHICLES

The paper deals with the detection process of energy loss in electric railway hauling vehicles. The importance of efficient energy use in railways and cost-effective rail transport tendency toward regenerative braking energy are considered. In addition, the current situation and improvement opportunities to achieve efficient energy use are examined. Seven measurement series were performed with scheduled Railjet trains between Hegyeshalom and Győr railway stations in Hungary. This railway section is related to the Hungarian State Railways' No. 1 main railway line (between Budapest-Kelenföld and Hegyeshalom state board), which is a part of the international railway line between Budapest and Vienna (capitals of Hungary and Austria, respectively). This double-track, electrified railway line with traditional ballasted superstructures and continuously welded rail tracks is important due to the international passenger and freight transport between Germany, Austria, and Hungary. The value of the regenerative braking energy can be even 20-30% of the total consumed energy. This quite enormous untapped energy can be used for several aims, e.g., for comfort energy demand (air conditioning, heating-cooling, lighting, etc.) or energy-intensive starts. The article also investigates the optimization of regenerative braking energy by seeking the energy-waste locations and the reasons for the significant consumption. The train operator's driving style and habit have been identified as one of the main reasons. Furthermore, train driver assistance systems are recommended to save energy, which is planned for future research

INVESTIGATION OF THE APPLICATION OF AUSTENITIC FILLER METALS IN PAVED TRACKS FOR THE REPAIR OF THE RUNNING SURFACE DEFECTS OF RAILS CONSIDERING FIELD TESTS

The current study aims to define a welding technology that allows for the repair of normal and heat-treated rails in paved tracks with partial dismantling and partial preheating in such a way that the resulting layer is not susceptible to cracking and can be done with minimal dismantling, even during night shifts or while traffic is present. High-elongation austenitic consumables (capable of approximately 2-3 times greater elongation than rails; rails have approximately 8-14% elongation) were used and tested for this purpose. Welds and rail tread defects were repaired on Hungary's busiest tram line (12-14 million gross tons per year), which also has a high axle load compared to other European tram lines. The repairs were performed on various rail grades using different layer numbers, and the experimental consumables were compared to conventional hardfacing welding methods. Welds were continuously monitored after welding, and surface hardness measurements were taken. A hardening function and an applicable technology were defined based on the results. The function compares the through-rolled axle tons to the expected hardness values over the first 6 million tons. Partial preheating and partial track disassembly can be used to weld a layer of hardness equal to the hardness of the rails and wheels

Investigation of railroad ballast particle breakage

Abstract This paper summarizes the authors' up-to-date results in the research topic of railway ballast particles' breakage test with individual laboratory test. In the past few years there were a lot of railway rehabilitation and maintenance project in Hungary, as well as abroad. The largest part of world's railways has traditional superstructure, i.e. they are so called ballasted tracks. The railway ballast is the highest mass in the railways' superstructure. Nowadays, it is a naturally fact that there is enough quantity of railway ballast in adequate quality. However, due to the modifications and restrictions in the related regulations since 2010, there are only few quarries in Hungary, which are able to ensure adequate railway ballast material for railway construction and maintenance projects for speed values between 120 and 160 km/h. Quarrying industry is stricken by aggravated environmental, heritage and conservation regulations year by year, it limits the accessibility of mineral wealth in significant manner. This fact with quality requirements means supply and quality risk in production of railway ballast in medium term. The main goal of authors' research is to be able to simulate the stress-strain effect of ballast particles in real and objective manner in laboratory circumstances, as well as in discrete element method modeling. This paper introduces the exact assembly of executed laboratory test and newest test results. The authors summarize the up-to-date international literature review, using that they give short outlook to the planned research with research directions in near future

Investigation of glued insulated rail joints with special fiber-glass reinforced synthetic fishplates using in continuously welded tracks

In this paper the authors partially summarize the results of a research on glued insulated rail joints with fiber-glass reinforced plastic fishplates (brand: Apatech) related to own executed laboratory tests. The goal of the research is to investigate the application of this new type of glued insulated rail joint where the fishplates are manufactured at high pressure, regulated temperature, glass-fiber reinforced polymer composite plastic material. The usage of this kind of glued insulated rail joints is able to eliminate the electric fishplate circuit and early fatigue deflection and it can ensure the isolation of rails’ ends from each other by aspect of electric conductivity

INVESTIGATION OF THE GLUED INSULATED RAIL JOINTS APPLIED TO CWR TRACKS

This article summarizes the research results related to our own conducted extensive laboratory tests of polymer composite and steel fishplated glued insulated rail joints (GIRJs), namely axial tensile tests as well as vertical static and dynamic tests. The investigation dealt with the examination of GIRJs assembled with steel and special glass-fiber reinforced plastic (polymer composite) fishplates, both of them for CWR railway tracks (i.e. so-called gapless tracks or, in other words, railway tracks with continuously welded rails). The exact rail joint types were MTH-P and MTH-AP, consistently. The MTH P types have been commonly applied for many years in the CWR tracks in Europe, mainly in Hungary. The MTH-AP rail joints consist of fishplates that are produced by the APATECH factory (Russia). They are made of a fiberglass-amplified polymer composite material at high pressure and controlled temperature. This solution can eliminate electrical fishplate lock and early fatigue failures just as it can ensure adequate electrical insulation. The advantage of such rail joints can be that they are probably able to ensure the substitution of the glued insulated rail joints with relatively expensive steel fishplates currently applied by railway companies, e.g. Hungarian State Railways (MÁV). The aim of the mentioned research summarized in this paper is to formulate recommendations on technical applicability and on the technological instructions that are useful in everyday railway operation practice on the basis of the measurements and tests carried out on rail joints in laboratory

The Prospect of Using the Dual Gauge Line for the Ukraine–Hungary Railway Connection

There are several international transport corridors in Hungary. Záhony railway station is one of the largest hubs in Europe, providing a railway connection between Ukraine and the European Union. Two different railway tracks meet and come together here, such as the standard (1435 mm) and broad (1520 mm) gauges. The availability of a developed infrastructure of the dual gauge on the territory of Hungary presupposes the corresponding development of the railway connection by Ukraine. In order to effectively use the dual gauge line and solve problems of special design, it is necessary to ensure the appropriate train flows. This research aims to provide scientific support for express analysis of the railway routes' competitiveness between Ukraine and the European Union to define the determining factors. The application of such approaches provides a tool for establishing the prospects for the development of existing railway lines, considering their features. Scientific approaches to creating methods for determining the priority areas of railway transport have been further developed. Apart from involving such essential indices as average speed and traffic volumes, the authors added the possibility of considering the presence of lines with such design features as single-track sections, non-electrified, dual gauge, etc., on the route. The theoretical background is applied as a tool for rapid calculations for increasing the competitiveness of the Chop–Záhony dual gauge line

Sustainability in railways – a review

This paper examines the sustainability of railways. A comprehensive international literature review was conducted on railway vehicles, traction, and railway permanent way. The main goal was to find the factors and parameters that affect railway sustainability the most. CO2 emissions from transportation, mining, raw material production, manufacturing, use, operation and maintenance, and demolition and restoration must be significantly reduced. Naturally, the attention will be on the considerable energy and financial savings. This article's main topics are sustainability, affordable and clean energy, industry, innovation, infrastructure, sustainable cities and communities, responsible consumption and production, climate action, and life on land. Building materials come from quarries and gravel pits, but availability is decreasing. Future pavement construction and maintenance require recycling demolition and industrial waste. Engineers must choose materials and technology that extend track lifetimes to ensure reliability, availability, maintainability, safety, sustainability, and economy in permanent railroad ways. Life-cycle costs can be reduced, e.g., by Building Information Modeling. Electric machinery is preferred for construction equipment, materials, and management. Sustainability, like grassed tracks and recyclable plastics, has improved urban life. Sheet metal forming using recycled materials and sustainability shows how important environmental protection is in car and train design. Electric road and rail propulsion are driven by environmental concerns, while supercapacitors and batteries are studied. In conclusion, by preferring rail for freight and passenger transport, both for private and public transport, energy savings and CO2 emissions can be up to 2-10 times higher than for other modes of transport

INVESTIGATION OF HEAT-AFFECTED ZONES OF THERMITE RAIL WELDINGS

The paper investigates the heat-affected zone (HAZ) of several rail joints executed by thermite rail welding (TW). The examined rail profile was 54E1 (UIC54). The rail steel categories were different: R260 and R400HT. The welding portions of the TWs fitted R350HT and R260 rail categories with normal welding gaps. The rail pieces were brand new, i.e., without any usage in the railway track. The authors executed Vickers-hardness tests (HV10) and material texture tests on the running surface of the rail head, as well as on slices cut from the rail head. The cutting was performed by the water jet method, five longitudinal direction slices with vertical cutting lines. The considered specimen lengths were 2×70 mm (i.e., 70 mm from the mid-point of the rail joint), however, the depths were 20 mm from the running surface. Therefore, the measuring spaces were 5 mm lengthwise and 2 mm in depth. The variation of the hardness values was determined considering the microstructures of the base steel material and the TW. For comparison, previously measured Elektrothermit SoW-5 and earlier own research were taken into consideration