Alternate Double Single Track Lines

Many capacity analyses using the UIC 406 capacity method for double track lines have been carried out and presented international, but few capacity analyses applying the capacity method to single track lines have been presented. Therefore, the differences between capacity analyses of double track lines and single track lines are discussed in this article. The principles of the UIC 406 of double track lines can be applied to single track lines—at least when more than one train follows each other in the same direction. In a presentation of the UIC 406 for single track operations, it is important to define where to divide the railway lines into line sections and how the conflicts between trains at crossing stations and junctions have to be analysed. The effects on railway networks with single track lines and their impact on capacity consumption are described to enable a consistent capacity statement.

Nowadays a considerable percentage of trains mature delays due to nodes and stations congestion. They are normally a combination of effects of routes conflicts in stations on lines and propagation in stations of delays suffered along the lines. Station areas represent the bottlenecks of railway operations, due to many incompatible train routes crossing each other that lead to many potential conflicts between trains. Goal of the research is to compare some literature methods to study nodes capacity, by application of if-then processes to analyze stability or variability of results obtained by various timetabling to occupy the minimum capacity and increase the number of trains. It is a typical critical circuit, which can be seen as the bottleneck of the timetable to prevent conflicts and delays. In order to tackle the purpose, the paper introduces synthetically the methods and applies them systematically to a complex network, including single and double track lines and various typologies of stations. The further development includes the comparative applications of the analytical methods, with respect to variation of input data, and of a simulation approach.

During the laser cladding process, thermal stresses are induced because of the high-energy input, high temperature gradient, fast cooling rate, and inconsistency of the clad-substrate material. The induced thermal stresses not only increase the crack tendency, but also influence the mechanical performance of the deposited layer. In this study, a three dimensional (3D) uncoupled thermo-mechanical finite element (FE) model was established to simulate the stress evolution of laser cladding of cobalt-based coatings on mild steel A36. The temperature field was simulated first and then used as transient thermal loading to simulate the stress evolution. Stress distributions for three cases: single track on a flat substrate, double-track on a flat substrate, and double-track on a cylindrical substrate, were investigated in detail. To check the accuracy of the simulation results, validation experiments were carried out using an 8-kW high-power direct diode laser. The thermocouples were used to monitor the temperature cycles at several marked points. The cross-sections of single and double tracks on a flat substrate obtained experimentally were compared with the simulation results. The residual stress on the clad was experimentally determined by an X-ray diffraction machine. The experimentally obtained data showed a significant consistency with the prediction results.

Railways in Indonesia still show problems, such as time delays. To make train services in Indonesia better, government efforts are needed, one of which is the development of new infrastructure, such as the construction of a double-track train such as Sepanjang to Mojokerto segment. So it is necessary to analyze the level of service both in existing conditions and after construction. The analysis was carried out in two conditions, namely, full single track and full double track. For full double-track reference, a simulation is carried out with an auxiliary program, namely the Railway Operation Simulator (ROS). By entering data in the form of station layouts, train facilities, and signaling systems and blocks. Based on the analysis results, it shows that the double track in the Sepanjang-Mojokerto segment affects the level of service. The prediction of service levels for the Sepanjang-Mojokerto segment shows that three road plots have LoS A. So, overall, with the construction of the double track, this segment is operating below capacity and has low traffic.

Railroads have long been serving the largest portion of freight ton-miles in the U.S. freight shipment market. The rising demand for rail transportation is expected to continue in the foreseeable future, and considerable network congestion and inefficiency will result. Thus, a systematic methodology is needed to predict freight flow concentrations and congestion patterns in the rail network. A customized network assignment model for rail freight shipment demand is proposed; in this model, single-and double-track lines are represented by an equivalent directed graph. A railroad-specific link cost function adjusted for single and double tracks is developed to capture traffic delay, and an adapted convex combination algorithm is developed to find the shipment routing equilibrium. This model is applied to an empirical case study for the U.S. rail network with national freight shipment demand in 2007. The resulting freight flow pattern is visualized graphically and validated with empirical data. The proposed modeling framework could be used to help public agencies and private companies predict rail network traffic and develop infrastructure investment strategies to reduce adverse social impacts imposed by rail traffic delay.

The direct laser writing (DLW) using femtosecond lasers allows for the inscription of 3D microstructures embedded inside optical materials. Based solely on the silver ions photochemistry, the DLW in silver‐containing glasses enables to locally induce inside glasses a unique combination of optical properties. The physical modifications of the material encompass not only a refractive index change, but also new physical properties like fluorescence, second‐ and third‐harmonic generations, and surface plasmon resonance. Numerous efforts are deployed to develop the DLW‐assisted silver photochemistry in phosphate glasses. However, this glass family is suffering from its near‐infrared optical cutoff as opposed to the silver‐doped gallo‐germanate glasses. With an extended mid‐infrared (mid‐IR) transmission, these glasses are synthesized via the melt‐quenching technique. Depending on the glass composition, either a glass matrix‐based single track (Type I) or a silver cluster‐based double track (Type A) of refractive index change is produced. By enabling an order of magnitude smaller structures than with Type I, Type A modification is further expanded to embed, for the first time, periodic structures below the inter‐track spacing. Demonstrated with a pitch down to 400 nm, these Type A–based periodic structures bring new insights through the fabrication of 3D diffractive gratings in mid‐IR glasses.

Simply supported pre-stressed concrete box-girder bridges are the most common bridge type found on high-speed railway and urban rail transit lines in China. A field experiment has been conducted on the Pixian Viaduct of the Chengdu–Dujiangyan Intercity Railway, where two kinds of simply supported pre-stressed concrete box-girder bridges with a standard span of 32 m are used, one single track and the other double track. Characteristics of the noise underneath the box-girder, far from the bridge, and near the bridge gap were measured and analyzed in the time and frequency domains during high-speed train passage, as was the vibration of the box-girder’s bottom plate. The variations of noise with distance and train speed at locations 1.5 and 9 m above ground level were measured and fitted using mathematical formulae. A simplified formula to predict near-field bridge-borne noise was proposed and verified. The peak bridge-borne noise frequency and its tonal characteristic at 50 and 63 Hz for the double-track and single-track box-girders, respectively, were interpreted in terms of bridge vibration and sound radiation efficiency, respectively. The vibration/noise transfer function and coherence were evaluated, showing that vibration resonance is more significant than acoustic coincidence and that the former is more important in terms of noise reduction.

The actual cooling load of underground stations in recent years has been much lower than the designed load thirty years ago. Therefore, it is important to estimate the actual load in the planning of cooling systems. In this study, the cooling load caused by train wind in an underground station was discussed and a field measurement and computational fluid dynamics (CFD) simulation were conducted. The main conclusions are as follows: (1) The measurement showed that air volume of the train wind was greatly affected by the train speed and the tunnel structure (single or double track). (2) In the CFD simulation, the train was modeled as a moving body to simulate train wind. The CFD simulation with a pressure loss model in the tunnel could reproduce the measurement. (3) The influence of train wind on the platform cooling system was examined by the CFD simulation in terms of an influence coefficient. In the Shin-Nihombashi station, the influence coefficient was approximately 0.38 in the area connecting to the tunnel while the coefficient was about 0.24 in the center area.

The author discusses some reconfiguration methods where faulty PEs are compensated for by spare PEs located in two rows/columns in/around a mesh-connected array since they have the advantages that the numbers of spare PEs and the network overheads for reconstructions are relatively small. First, the author discusses how arrangements of spare PEs and network architectures affect the efficiencies of reconfigurations. As arrangements of spare PEs, he considers the cases where either spare linear arrays face each other or are located orthogonally. As replacements of faulty PEs by spare PEs, straight shifts using double or single tracks are considered. Reconfiguration algorithms are given for the proposed methods. The efficiencies of reconfigurations for the methods, that is, the reconfiguration probabilities, are compared with each other. Finally, the author presents built-in self-reconfiguring systems for the proposed methods by hardware. This implies that the proposed methods are effective in enhancing the run-time reliabilities as well as the fabrication-time yields of the processor arrays.

Planning and scheduling efficient heavy rail track maintenance through a Decision Rules Model

In experiments searching for neutrinoless double-beta decay, the possibility of identifying the two emitted electrons is a powerful tool in rejecting background events and therefore improving the overall sensitivity of the experiment. In this paper we present the first measurement of the efficiency of a cut based on the different event signatures of double and single electron tracks, using the data of the NEXT-White detector, the first detector of the NEXT experiment operating underground. Using a 228Th calibration source to produce signal-like and background-like events with energies near 1.6 MeV, a signal efficiency of 71.6 ± 1.5 stat± 0.3 sys% for a background acceptance of 20.6 ± 0.4 stat± 0.3 sys% is found, in good agreement with Monte Carlo simulations. An extrapolation to the energy region of the neutrinoless double beta decay by means of Monte Carlo simulations is also carried out, and the results obtained show an improvement in background rejection over those obtained at lower energies.

Most of the research addressing energy efficiency improvements on existing conventional railway lines is essentially from the point of view of train operation and does not analyse the possibilities that small actions on the railway infrastructure can bring. This fact is particularly significant for freight trains, whose movement is severely conditioned by uphill gradients, crossing points and speed restrictions. This article considers a conventional railway line, assessing the results, from the point of view of energy efficiency gains, of local upgrades of the existing railway infrastructure. The results obtained show that surgical interventions on existing railway infrastructure would improve the energy efficiency of freight trains, which is part of decarbonisation policies and the fight against climate change. This kind of analysis can constitute a new contribution to decision-making processes, which will contribute to the achievement of the objectives assumed by the European Union.

This paper shows the planning of time-optimal trajectories, which allows an autonomous race car to drive at the handling limits, taking into account locally changing road friction values. For this purpose, the minimum lap time problem is described as an optimal control problem, converted to a nonlinear programme using direct orthogonal Gauss-Legendre collocation and then solved by the interior-point method IPOPT. Reduced computing times are achieved using a curvilinear abscissa approach for track description, algorithmic differentiation using the software framework CasADi, and a smoothing of the track input data by approximate spline regression. The vehicle's behaviour is approximated as a single track and double track model with quasi-steady state tyre load simplification and nonlinear tyre model. The results are used to evaluate which vehicle physics are important for the calculation of the time-optimal trajectory. The novelty of this work is the consideration of wheel-specific tyre-road friction coefficients along the racetrack using a track friction map. It is shown that variable friction coefficients have a significant impact on the trajectory, and therefore significantly improve lap times on inhomogenous racetracks. The proposed trajectory planning has proven its practical suitability in first tests on an autonomous race car and will be used in the coming racing season in the Roborace competition.

The IF filter is a key component in modern mobile radio receivers. Depending on the system design, the filter requirements goes from a very smooth prefiltering to a complete channel filtering. SPUDTs based structures are well suited for fractional bandwidths typically between 0.1% and 0.5%. Due to the reflectors presence inside the transducers, SPUDTs allows many different filters structures mostly using its reflective characteristic, its transduction characteristics or both. For base station applications, rejections in the 80 dB range are required. The first way to obtain as high a rejection is to use a cascade of 2 filters. We present a cascade of 2 filters at 201 MHz. The first is a classical SPUDT while the second is a new double track structure. A simple means to obtain as high a rejection in a single filter is to use a reflective array structure. We present a 71 MHz filter using this technique. The rejection is more than 75 dB for a 170 kHz 3 dB bandwidth and a 470 kHz 50 dB bandwidth. The simplest SPUDT structure consists of two SPUDTs on a single track. Due to its lack of symmetry, this structure is not well suited for balanced drive. A symmetric SPUDT structure was developed to fix this problem. Two balanced drive SPUDT filters are shown. The first is a 71 MHz GSM prefilter while the second is 85.4 MHz filter for CDMA. This filter exhibits a 0.85 MHz p0.2 dB bandwidth, a 1.7 MHz 40 dB bandwidth for a 14 dB insertion loss

The subject of the research is Chinese investments in the modernization and reconstruction of railway infrastructure in Serbia, with a focus on the construction of the Belgrade-Budapest high-speed rail line up to 200 km/h, on the sections Belgrade-Stara Pazova and Novi Sad-Subotica-Kelebija. The research aims to analyze the impact of Chinese investment projects on the railway infrastructure in Serbia and examine the effects of projects' implementation at different levels, including the challenges they face. The analysis covers the traffic, technical-technological and financial aspects of the project. The importance of building a high-speed railway through Serbia, but also of the shortest railway connection from Western and Central Europe in the countries of Southern Europe and the Middle and the Far East, is considered, especially in the context of the cooperation within the BRI. The research results are the presentation of the effects railway infrastructure projects have on the development of Serbian economy, as well as the challenges that arise during the implementation process.