Railway Track Stress–Strain Analysis Using High-Precision Accelerometers

We propose a new approach for railway path diagnostics on the basis of track line stress–strain analysis using the data provided by high-precision accelerometers. This type of sensor provides sufficient accuracy with lower costs, and enables the development of a railway digital twin, according to the concept of the Internet of Things. The installation of sensors on a railway track along its entire length allows real-time monitoring of the states of the technical parameters of the railway track, and using mathematical methods to evaluate its wear on the basis of constantly received data. This paper presents an original 3D model of a railway track line and the results of its analysis using a finite element method. To test the model, we performed an analysis of the normal stresses and deformations in the elements of a railway track by simulating the impact of rolling stock on a section of a railway track with intermediate rail fastenings, ZhBR-65SH. The research results were probated and tested at the testing ground of the Kuibyshev branch of Russian Railways, the Samara track. The proposed approach makes it possible to determine the load of the track, and knowing the movement of the rail, to calculate the structural stress in the elements of the railway track, to constantly monitor the parameters of the slope and rail subsidence.

Is it Possible to Get a SAR Image of Ocean Waves Free of Spectral Cut-off by Direct Measurement?

A method of SAR sounding of the ocean surface is proposed, which is capable of providing an undistorted by spectral cut-off wave pattern. The method involves the use of two synchronized SARs, which look across the track line and illuminate the same area of the surface. Each SAR records its own backscattered signal, which are then multiplied with each other and the resulting signal is undergoing the procedure of matched filtering. Numerical estimates of the applicability conditions of the method are carried out.

NONLINEAR ROLL CONTROL ALGORITHM FOR THE DERIVATION OF AN AIRCRAFT LEAVING ON A PRESCRIBED WAY LINE

The conclusion of the aircraft to a given track line is considered. The possibility of using for this purpose a nonlinear roll control algorithm with functions of functions is analyzed. The results of modeling of the guidance process are given, showing that the investigated nonlinear algorithm ensures the withdrawal of an aircraft from any points in space on a given path for any initial course in a calm atmosphere and in the presence of wind. Key words: line of a given path, roll control, trajectory control algorithm, motion control of the center of mass, lateral deviation.

Review of the project of reconstruction of the existing and reconstruction of the second track on the section Hrvatski Leskovac - Karlovac

The Hrvatski Leskovac - Karlovac section is located on the M202 Zagreb GK - Rijeka railway line, which is part of the Mediterranean corridor of the EU core network. The section is currently a single-track line, and represents a bottleneck in terms of infrastructure capacity. The project envisages the reconstruction of the existing and construction of the second track with the reconstruction of the existing stations in order to meet the conditions of interoperability, the transformation of individual stations into stops, and the reconstruction of existing stops. Some of the existing railway-road crossings will be delevelled by constructing crossroads in two levels (underpasses and overpasses), some will be eliminated with the construction of connection roads and some will be reconstructed. The project is currently in the contracting phase of works and supervisions. In the period from 2017 until today, the Ministry of Environmental Protection and Energy (MZOE) Decision was published on the Environmental Impact Study, the Location Permit was obtained, and the Feasibility Study was completed and approved by the JASPERS Mission in the Republic of Croatia.

Antarctic pack ice seal observations during spring across the Lazarev Sea

The distribution, density and percentage contribution of pack ice seals during ship-board censuses in the marginal sea ice zone beyond the Lazarev Sea in spring 2019 are presented. Adult/juvenile crabeater seals (n = 19), leopard seals (n = 3) and Ross seals (n = 10) were sighted during 582.2 nm of censuses along the ship’s track line in the area bounded by 00°00’–22°E and 56°–60°S. Antarctic fur seals (n = 21) were only encountered on the outer fringes of the pack ice, and Weddell seals were absent due to their primary use of fast ice and inner pack ice habitats close to the coast. Crabeater seal sightings included juveniles (n = 2) and another four groups of 2–3 unclassified crabeater seals, singletons (n = 5), single mothers with pups (n = 3) and a family group (n = 1 triad). Only one leopard seal attended a pup, while no Ross seal pups were located. The survey was likely of insufficient effort, in both extent (north of 60°S) and duration (18 days), to locate seals in considerable numbers this early (late October/early November) in their austral spring breeding season.

Distribution and Abundance of the Eastern Canada – West Greenland Bowhead Whale Population Based on the 2013 High Arctic Cetacean Survey

The hunting of bowhead whales (Balaena mysticetus) is an integral part of Inuit culture. An up-to-date abundance estimate of the entire Eastern Canada – West Greenland (EC-WG) bowhead population is necessary to support sustainable management of this harvest. The High Arctic Cetacean Survey (HACS) was conducted in August 2013, primarily to update abundance estimates for known stocks of Baffin Bay narwhal (Monodon monoceros). As the ranges of narwhal and bowhead largely overlap, the survey area was expanded to cover the summer range of bowhead whales. Bowhead whale abundance was estimated using 3 aircraft to cover the large survey area within a short time frame. Distance sampling methods were used to estimate detection probability away from the track line. Double platform with mark-recapture methods were used to correct for the proportion of whales missed by visual observers on the track line (perception bias). Abundance in Isabella Bay, an area known for high bowhead density, was estimated using density surface modelling to account for its complex shape and uneven coverage. Estimates were corrected for availability bias (whales that were not available for detection because they were submerged when the aircraft passed overhead) using a recent analysis of satellite-linked time depth recorders transmitting information on the diving behaviour of bowhead whales in the study area in August of the same survey year. The fully corrected abundance estimate for the EC-WG bowhead whale population was 6,446 (95% CI: 3,838–10,827). Possible sources of uncertainty include incomplete coverage and the diving behaviour of bowhead whales. These results confirm earlier indications that the EC-WG stock is continuing to recover from past overexploitation.

Narwhal Abundance in the Eastern Canadian High Arctic in 2013

In summer, narwhals (Monodon monoceros) migrate from Baffin Bay to northeastern Canada and northwest Greenland, where they are hunted by Inuit for subsistence. To prevent localized depletion, management of narwhals is based on summer stocks. The High Arctic Cetacean Survey (HACS), conducted in August 2013, was the first survey to estimate abundance of all 4 Canadian Baffin Bay narwhal summer stocks, as well as putative stocks in Jones Sound and Smith Sound, in the same summer. Narwhal abundance was estimated using a double-platform aerial survey. Distance sampling methods were used to estimate detection probability away from the track line. Mark-recapture methods were used to correct for the proportion of narwhals missed by visual observers on the track line (i.e., perception bias). We used a data-driven approach to identify single and duplicate sightings, using 4 covariates to compare differences in sightings made by front and rear observers based on: time of sighting, declination angle, group size, and species identity. Abundance in fjords was estimated using density surface modelling to account for their complex shape and uneven coverage. Estimates were corrected for availability bias (narwhals that are not available for detection because they are submerged when the aircraft passes overhead) using a new analysis of August dive behaviour data from narwhals equipped with satellite-linked time depth recorders. Corrected abundance estimates were 12,694 (95% CI: 6,324–25,481) for the Jones Sound stock; 16,360 (95% CI: 3,833–69,836) for the Smith Sound stock; 49,768 (95% CI: 32,945–75,182) for the Somerset Island stock; 35,043 (95% CI: 14,188–86,553) for the Admiralty Inlet stock; 10,489 (95% CI: 6,342–17,347) for the Eclipse Sound stock; and 17,555 (95% CI: 8,473–36,373) for the East Baffin Island stock. Total abundance for these 6 stocks was estimated at 141,908 (95% CI: 102,464–196,536). Sources of uncertainty arise from the high level of clustering observed, in particular in Admiralty Inlet, Eclipse Sound, and East Baffin Island, as well as the difficulty in identifying duplicate sightings between observers when large aggregations were encountered.

Simulation Study of the IAMSAR Standard Recovery Maneuvers for the Improvement of Serviceability

Recovery maneuvers are highly important for rescuing a person overboard at sea. This is the prime reason why the International Maritime Organization (IMO) has published the International Aeronautical and Maritime Search and Rescue (IAMSAR) Manual III, which aims to assist vessels and aircrafts in the performance of a search, rescue, or on-scene co-ordinated efforts with aspects of search and rescue (SAR) which pertain to their own emergencies. The IAMSAR Manual III includes the Williamson turn, the Anderson turn and the Scharnov turn. Furthermore, the Lorén turn has been newly included in the 2019 edition of the Manual. Although several studies have pointed out that the Williamson turn needs to be applied in a modified form for proper application, in terms of returning ability to the original track line, it has not yet been modified in the Manual. Therefore, the purpose of this study is to analyze the serviceability of the four standard recovery maneuvers through a series of ship-handling simulations with representative types of ships. Our main results are as follows: firstly, the Anderson turn is the fastest recovery method, regardless of engine power and rudder efficiency; secondly, the actual paths of the Williamson turn are not consistent with the expected ones; and, finally, no correlations were found between the returning ability of the Williamson turn and any ship configuration or maneuvering ability factors, or their combinations. Thus, based on the experimental results, this paper proposes revising the descriptions of the standard recovery maneuvers and IMO regulations on ship maneuverability, as well as posting the actual tracks of the Williamson turn on the bridge in order to improve its serviceability.

A Multiobjective Integer Linear Programming Model for the Cross-Track Line Planning Problem in the Chinese High-Speed Railway Network

In China, cross-track high-speed trains (CTHSTs) play an important role in railway passenger transportation, with an increasing number of cross-track passengers sourced from the expansion of high-speed railway (HSR) network. The CTHST generally has long travel times, so running CTHSTs is not beneficial for train rescheduling work and plan’s periodicity in the periodic operation context. Thus, the main challenge in cross-track line planning is looking for a symmetry point between passenger transportation and disadvantages of running CTHSTs, which are two conflicting aspects. In this study, we developed a multiobjective integer programming model to produce a balanced cross-track line plan by combining individual-track high-speed trains (ITHSTs) into CTHSTs, which is a discrete optimization problem. This strikes a balance among four goals: the periodicity of the line plan, CTHST quantity, CTHST mileage, and CTHST stops in the context of periodic operation, while satisfying the constraints of passenger demand and the number of available ITHSTs. Numerical experiments are conducted based on a real-world network and optimal solutions were quickly obtained. We analyzed impacts of each goal and parameter on the result and influencing factors of computation. Comparisons with existing methods and real-life plans were also presented to show improvements made by proposed model.