Sustainability of Water Resources in Karst Undermined by Tunneling: A Case Example

Water resources in karsts are scarce due to the high cavernosity in the otherwise low-permeability limestone rock mass. The highly variable porosity and transmissivity of karst aquifers are caused by a network of channels, caverns, and caves that typically act as water-bearing, connected vessels. Tunneling in a karst environment can severely deplete an aquifer and undermine the sustainability of water resources over the long term. A research study was carried out to elaborate and develop measures for the sustainable preservation of the water resources in a Slovenian karst, in which two approximately 7 km-long tunnels will be driven as part of the construction of the new Divača–Koper railway line. Hydrogeological site investigations were carried out with an aim to evaluate the transmissivity and spatial spreading of the karst aquifer along the route of the tunnels, including the observation of the long-term variation of the groundwater levels and trace experiments. The main findings, which are presented in this paper, were used to develop a methodology for the selection of adequate measures for tunnel construction with an aim of ensuring the sustainability of water resources in karst aquifers. The construction measures comprise limiting the inflows using injection grouting, obscuring the groundwater intake by undrained sections of the tunnel, and constructing bypasses around the tunnel to preserve the current groundwater flow regime. The presented methodology of dynamically accommodating the preventive measures to the actual hydrogeological conditions onsite is generally applicable for common cases in which the state of the karst aquifer could not be pre-determined with a sufficient accuracy of tens of meters to a meter. The spatially and temporally continuous hydrogeological investigations and decision-making charts to reduce the tunnelling’s impact on the karst aquifer are explained in detail in this paper.

Tin and Antimony as Soil Pollutants along Railway Lines—A Case Study from North-Western Croatia

The aim of this study was to determine the extent and patterns of antimony and tin contamination in soils along railway lines, as there are very few data in the literature on this subject. The study was conducted in north-western Croatia. Total and bioavailable concentrations of Sn and Sb were detected using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). The following results were obtained: total concentrations of Sb ranged from 0.98 to 52.0 mg/kg and of Sn from 3.04 mg/kg to 97.6 mg/kg. The soil samples showed pronounced Sb and Sn enrichment, up to 87 and 33 times the median value for European soils, respectively. In contrast to the total concentrations, the bioavailable concentrations showed relatively low values. For Sn, the percentage of total content ranged from 0.001 to 0.021%, while for Sb it ranged from 0.001 to 0.136%. Statistical data analysis suggests that the distribution of Sb and Sn in soils near railway lines is influenced by the functional use of the site, distance from the tracks, topography, age of the railway line, and also by soil properties such as soil texture, humus content, and soil pH. This study demonstrates that rail transport is a source of soil pollution with Sn and Sb. The origin of Sb and Sn enrichment is abrasion by brakes, rails, wheels, freight losses, exhaust gasses, etc. Both elements in soils along railway lines pose an environmental risk to humans, agricultural production, and wildlife, and therefore further detailed studies are required.

India, Russia and Iran: a New Study on “North — South” International Transport Corridor

The International North-South Transport Corridor (INSTC) has made impressive progress in making boat, street, and rail courses that transport cargo between India, Iran and Russia and countries of the European Union and Central Asia. It connects India Ocean, Iran, the Persian Gulf nations, through the nations of the Caucasus and Central Asia with Russia and mainland Europe. This task was a reaction to Eurasian coordination, “Extraordinary Eurasian Partnership” (Russia, 2011) including “One Belt, One Road” (China, 2013) and The Silk Road. By rethinking the Integration and Economic Potential of the INSTC and its importance for the partaking nations, it is feasible to utilize the rationale of the aggregate game plan of the Eurasian space in light of a legitimate concern for all member states. However, the first trail train via INSTC, departing from Helsinki on June 21, 2021, arrived at its destination at twice the speed of the existing Suez Canal route, proving the timeliness and competitiveness but missing rout in Iran Rasht-Astara railway line still remain the challenging problem for the Iranian government as well as for India and Russia.

Iron Silk Road Trans-Caspian East-West-Middle Corridor Initiative and Baku-Tbilisi-Kars Railway Line

The East-West Middle Corridor (Middle Corridor) with the Caspian Transit, which starts from Turkey with the Baku Tbilisi Kars Railway line, reaches the Caucasus region. From here it travels over the Caspian Sea through Turkmenistan and Kazakhstan to Central Asia and China and is one of the most important components of historical silk road resuscitation project. With this study, the contribution of Baku Tbilisi Kars railway line and Kars Logistics Center, which is the European and Turkish gateway of the middle corridor, to the silk railway in terms of international leasing is explored.

Combined optimisation and MCDA based solution of the tram depot location problem

This paper deals with an issue of technical facilities location in a public transport system. The decision problem is formulated as a selection of the most advantageous alternative, i.e. the location of a new tram depot among the already existing facilities of this type. The selection is preceded by the evaluation of the alternatives. The assessment is not a trivial task, because there are many groups of interest with usually contradictory points of view. Therefore, the evaluation of the new tram depot locations should represent different aspects, e.g., economical, technical, environmental, and organizational. To handle such a complex decision problem the authors propose a methodology, which is a composition of the optimisation and multiple criteria evaluation techniques. The developed methodology is experimentally applied to the selection of one out of five tram depot locations in the public transport system of the city of Poznan, Poland. All the computational experiments are performed by means of optimization and multiple criteria decision aiding (MCDA) methods and tools, i.e. a linear optimization engine Solver Premium Platform and AHP method with its application AHORNsimple. The calculations are the basis for recommending the location of a new depot in the central part of the transport system network, which is a reasonable solution taking into account, e.g. the proximity of the main railway line, the possibility of triple distribution of the transport means from depot. The proposed methodology of the decision problem solution gives also an opportunity to create the hierarchy of considered tram depot locations as well as to compare the position in the ranking of the best solution with the existing one. Since the proposed methodology assumes the selection of the most suitable MCDA method to the problem under consideration and the decision maker’s preferen¬ces, it guarantees that the result of analysis becomes reliable and the decision aiding process is credible.

Dynamic Wheel-Rail Force-Based Track-Irregularity Evaluation for Ballasted Track on Serviced Railway by Adjacent Excavation

This study investigates a load-based, track-irregularity-analysis technique for ballasted tracks on a serviced railway line with respect to excavation work conducted in adjacent sites. A numerical analysis and field measurements (railbed-settlement-monitoring sensor, track-geometry-measurement system, wheel-load measurements) were analyzed comparatively to demonstrate the correlation between the track irregularities and the Wheel-Rail interaction force. In this way, we highlight the necessity for load-based track-irregularity-management methods. The analyzed results show that the maximum dynamic wheel load was measured in the range of approximately 10 m before and after the location where the maximum track irregularities occurred, and that even if the maintenance criteria of track irregularities were satisfied, the design dynamic wheel load could still be exceeded depending on the train speed, thus indicating that track damage can be caused by the impact load.

Evaluation of the effect of JSC RZD transportation infrastructure availability on the risks of losses in the process of transportation

Aim. The availability of transportation infrastructure facilities affects the quality of the transportation services provided by JSC RZD. At the same time, this effect may significantly differ depending on the operating conditions of the transportation infrastructure or a specific railway line and can cause various degrees of risk of damage to the transportation process. Such risks are defined as risks of train-hour losses due to transportation infrastructure failures. Planning dependability management activities under conditions of scarce resources requires targeted identification of the transportation infrastructure facilities whose availability most significantly affects the magnitude of the risks of damage to the transportation process. The aim of the paper is to develop a method for evaluating daily availability and identifying its correlation with the risk of train-hour losses. Methods. The authors used the methods of risk management, probability theory and mathematical statistics, correlation and regression analysis. Results. The paper suggests representing the daily availability indicator of JSC RZD’s transportation infrastructure facilities as a two-parameter gamma distribution and describing its effect on the risks of the transportation process with a regression model. Conclusions. The paper’s findings can be used as part of transportation infrastructure dependability planning and targeted allocation of resources, as well as for substantiating the dependability indicator when evaluating the practical capacity of railway lines and utilization ratio and in a number of other operational tasks.

Experimental and Numerical Verification of the Railway Track Substructure with Innovative Thermal Insulation Materials

The article aims to present the modified structural composition of the sub-ballast layers of the railway substructure, in which a part of the natural materials for the establishment of sub-ballast or protective layers of crushed aggregate is replaced by thermal insulation and reinforcing material (layer of composite foamed concrete and extruded polystyrene board). In this purpose, the experimental field test was constructed and the bearing capacity of the modified sub-ballast layers’ structure and temperature parameters were analyzed. A significant increase in the original static modulus of deformation on the surface of composite foamed concrete was obtained (3.5 times and 18 times for weaker and strengthen subsoil, respectively). Based on real temperature measurement, it was determined the high consistency of the results of numerical analyses and experimental test (0.002 m for the maximum freezing depth of the railway line layers and maximum ±0.5 °C for temperature in the railway track substructure–subsoil system). Based on results of numerical analyses, modified railway substructure with built-in thermal insulating extruded materials (foamed concrete and extruded polystyrene) were considered. A nomogram for the implementation of the design of thicknesses of individual structural layers of a modified railway sub-ballast layers dependent on climate load, and a mathematical model suitable for the design of thicknesses of structural sub-ballast layers of railway line were created.

Effects of a Threat and Alliance on International Cooperation: Comparison of Inter-Korean and Turkish-Armenian Railway Projects

The article examines restricting factors in international cooperation, drawing a comparative analysis of two cases on cross-border infrastructure projects: the Gyeongui railway line that connects North and South Korea and the Kars-Gyumri-Tbilisi railway line that links Turkey and Armenia. In both cases, states involved strive for the normalization of diplomatic relations and border openness as well as potential economic opportunities and national security. Nevertheless, neither Seoul and Pyongyang nor Ankara and Yerevan succeeded in building a sustainable cooperation framework. While the outcome is the same, independent variables in both cases are different. Firstly, two Koreas have been in a military confrontation for seven decades, whereas Turkey and Armenia never engaged in a direct conflict. Secondly, the configuration of alliances (South Korea and the United States and Turkey and Azerbaijan) weakens the decision-making on the troublesome infrastructure projects. Consequently, alliances are identified as one the key factors that determine the mode of international cooperation.

Method for Designing Robust and Energy Efficient Railway Schedules

The robustness of the timetable is a sensitive issue in the daily realization of railway operations. As shown in the paper, robustness is a function of time reserves that helps to prevent unscheduled stops resulting from traffic disruptions and causing a higher energy consumption. The correct handling of time reserves while scheduling is a multidimensional issue, and it has a significant influence on the energy consumption of railway traffic. Therefore, the paper aims to show a simulation-based method, taking into account failure occurring probabilities and their consequences to get an acceptable level of robustness, that can be quantified by the probability of no delay propagation. This paper presents a method for the addition of time margins to the railway timetable. The iterative time buffer adding method is based on operational data as a knowledge source, to achieve the punctuality target. It was verified on a real railway line. An analysis of energy consumption for unscheduled train stops depending on the added buffer time was conducted after the literature review and the presentation of the evaluation model. The paper ends with discussion of the results and conclusions.