Rail Flaw Detection via Kolmogorov Entropy of Chaotic Oscillator Based on Ultrasonic Guided Waves

Ultrasonic guided wave (UGW) inspection is an emerging non-destructive testing(NDT) technique for rail flaw detection, where weak UGW signals under strong noise backgrounds are difficult to detect. In this study, a UGW signal identification model based on a chaotic oscillator is established. The approach integrates the UGW response into the critical state of the Duffing system to serve as a disturbance control variable. By evaluating the system's motion state before and after introducing the UGW response, identification of UGW signals can be realized. Thus, the parameters defining the critical state of Duffing oscillators are determined by Ke. Moreover, an electromagnetic transducer was specifically devised to enable unidirectional excitation for UGWs targeted at both the rail base and rail head. Experimental studies showed that the proposed methodology effectively detected and located a 0.46 mm notch at the rail base and a 1.78 mm notch at the rail head. Furthermore, Ke was directly proportional to the notch size, which could be used as a quantitative index to characterize the rail flaw.

Station-Level Effects of the COVID-19 Pandemic on Subway Ridership in the Seoul Metropolitan Area

This paper investigates the station-level impacts of the coronavirus disease (COVID-19) pandemic on subway ridership in the Seoul Metropolitan Area. Spatial econometric models are constructed to examine the association between ridership reduction caused by the pandemic and station-level characteristics during the pandemic years 2020 and 2021. The results reveal unequal effects on station-level ridership, based on the pandemic waves, the demographics, and the economic features of pedestrian catchment areas. First, the subway system was severely disrupted by the pandemic, with significant decreases in ridership-by about 27% for each of the pandemic years-compared with the pre-pandemic year (2019). Second, the ridership reduction was sensitive to the three waves in 2020 and responded accordingly; however, it became less sensitive to the waves in 2021, indicating that subway usage was less responsive to pandemic waves during the second year of the pandemic. Third, pedestrian catchment areas with higher numbers of younger residents (in their 20s) and older residents (65 years and older), those with more businesses requiring face-to-face interactions with consumers, and stations located in the employment centers were hit the hardest in ridership reduction caused by the pandemic.

How Well Did U.S. Rail and Intermodal Freight Respond to the COVID-19 Pandemic versus the Great Recession?

This paper analyzes and compares patterns of U.S. domestic rail freight volumes during and after the disruptions caused by the 2007-2009 Great Recession and the COVID-19 pandemic in 2020. Trends in rail and intermodal (IM) shipment data are examined in conjunction with economic indicators, focusing on the extent of drop and recovery of freight volumes of various commodities and IM shipments, and the lead/lag time with respect to economic drivers. Impacts of the Great Recession and the rebound from it were slow to develop, whereas COVID-19 produced both profound disruptions in the freight market and rapid rebound, with important variations across commodity types. Demand for energy-related commodities (coal, petroleum, and fracking sand) dropped during the pandemic whereas demand for other commodities (grain products and lumber, and IM freight) rebounded rapidly and in some cases grew. Overall, rail freight experienced a rapid rebound following the precipitous drop in traffic in March and April, 2020, achieving a near-full recovery in 5 months. As the recovery proceeded through 2020, IM flow, containers moving by rail for their longest overland trips, rebounded strongly, some exceeding 2019 levels. In contrast, rail flows during the Great Recession changed slowly with the onset and recovery extending over multiple years. Pandemic response reflected the impacts of quick shutdowns and a rapid shift in consumer purchasing patterns. Results for the pandemic illustrate the resilience of the U.S. rail freight industry and the multifaceted role it plays in the overall logistics system. Amid a challenging logistic environment, freight rail kept goods moving when other methods of transport were constrained.

Bioprotection of Transportation and Facilities from SARS-CoV-2 (COVID-19)

The recent COVID-19 pandemic has led to a nearly world-wide shelter-in-place strategy. This raises several natural concerns about the safe relaxing of current restrictions. This article focuses on the design and operation of heating ventilation and air conditioning (HVAC) systems in the context of transportation. Do HVAC systems have a role in limiting viral spread? During shelter-in-place, can the HVAC system in a dwelling or a vehicle help limit spread of the virus? After the shelter-in-place strategy ends, can typical workplace and transportation HVAC systems limit spread of the virus? This article directly addresses these and other questions. In addition, it also summarizes simplifying assumptions needed to make meaningful predictions. This article derives new results using transform methods first given in Ginsberg and Bui. These new results describe viral spread through an HVAC system and estimate the aggregate dose of virus inhaled by an uninfected building or vehicle occupant when an infected occupant is present within the same building or vehicle. Central to these results is the derivation of a quantity called the "protection factor"-a term-of-art borrowed from the design of gas masks. Older results that rely on numerical approximations to these differential equations have long been lab validated. This article gives the exact solutions in fixed infrastructure for the first time. These solutions, therefore, retain the same lab validation of the older methods of approximation. Further, these exact solutions yield valuable insights into HVAC systems used in transportation.

Traffic-Related High Sleep Disturbance in the LIFE-Adult Cohort Study: A Comparison to the WHO Exposure-Response-Curves

Sleep is negatively affected by environmental noise. In the present study, we investigated self-reported high sleep disturbances (being "highly sleep disturbed"-HSD) from road traffic (primary and secondary road networks), rail (train and tram) and air traffic noise in the LIFE-Adult cohort study in Leipzig, Germany. For this, we used exposure data from 2012 and outcome data of Wave 2 (collected during 2018-2021). HSD was determined and defined according to internationally standardized norms. The highest risk for transportation noise-related HSD was found for aircraft noise: the odds ratio (OR) was 19.66, 95% CI 11.47-33.71 per 10 dB increase in L_night. For road and rail traffic, similar risk estimates were observed (road: OR = 2.86, 95% CI 1.92-4.28; rail: OR = 2.67, 95% CI 2.03-3.50 per 10 dB L_night increase). Further, we compared our exposure-risk curves with the curves of the WHO environmental noise guidelines for the European region. The proportion of individuals with HSD for a given noise level was lower for rail traffic but higher for aircraft noise in the LIFE study than in the WHO curves. For road traffic, curves are not directly comparable because we also included the secondary road network. The results of our study add to the body of evidence for increased health risks by traffic noise. Moreover, the results indicate that aircraft noise is particularly harmful to health. We recommend reconsidering threshold values for nightly aircraft exposure.

Analysis of Electromagnetic Characteristics of Copper-Steel Composite Quadrupole Rail

The ablation and wear of the four-rail electromagnetic launcher during the working process will aggravate the damage of the armature and rail, and greatly affect the service life of the launcher. To effectively alleviate rail damage, this paper applies the copper-steel composite rail to the four-rail electromagnetic launcher and proposes a new four-rail electromagnetic launcher. Based on the quadrupole magnetic field theory, the physical model of the new four-rail electromagnetic launcher is established, and the electromagnetic characteristics of the ordinary and new launchers are compared and analyzed using the finite element method. On this basis, the influence of composite layer parameters on the electromagnetic characteristics of copper-steel composite quadrupole rail is explored. The study found that the new four-rail electromagnetic launcher can provide a better launch magnetic field environment for smart loads, and the current distribution of the armature and the rail contact surface is more uniform, which can effectively improve the contact condition between the armature and the rail. The composite layer parameters of copper-based composite rail will have a certain impact on electromagnetic characteristics, and copper-steel composite rail of appropriate proportions can be selected according to different needs. The model proposed in this paper has a certain degree of scientificity and rationality.

Identifying and mitigating the impacts on primates of transportation and service corridors

Most primate populations are declining; 60% of species face extinction. The expansion of transportation and service corridors (T&S) (i.e., roads and railways and utility and service lines) poses a significant yet underappreciated threat. With the development of T&S corridors predicted to increase across primates' ranges, it is necessary to understand the current extent of its impacts on primates, the available options to mitigate these effectively, and recognize research and knowledge gaps. By employing a systematic search approach to identify literature that described the relationship between primates and T&S corridors, we extracted information from 327 studies published between 1980 and 2020. Our results revealed that 218 species and subspecies across 62 genera are affected, significantly more than the 92 listed by the IUCN Red List of Threatened Species. The majority of studies took place in Asia (45%), followed by mainland Africa (31%), the Neotropics (22%), and Madagascar (2%). Brazil, Indonesia, Equatorial Guinea, Vietnam, and Madagascar contained the greatest number of affected primate species. Asia featured the highest number of species affected by roads, electrical transmission lines, and pipelines and the only studies addressing the impact of rail and aerial tramways on primates. The impact of seismic lines only emerged in the literature from Africa and the Neotropics. Impacts are diverse and multifaceted, for example, animal-vehicle collisions, electrocutions, habitat loss and fragmentation, impeded movement and genetic exchange, behavioral changes, exposure to pollution, and mortality associated with hunting. Although several mitigation measures were recommended, only 41% of studies focused on their implementation, whereas only 29% evaluated their effectiveness. Finally, there was a clear bias in the species and regions benefiting from research on this topic. We recommend that government and conservation bodies recognize T&S corridors as a serious and mounting threat to primates and that further research in this area is encouraged.

A policy response to workplace innovation for the rail sector

The rail sector is a sector with a significant impact on European industry and it is therefore important that it follows the current innovative trends. We live in an increasingly digitised society but, until now, digitisation has not been a priority issue for the sector as the rules that apply to the entire value chain have hindered the digitisation process. Even so, technologies are not enough, and innovation must be implemented in companies at the organisational and employee level. The RailActivation project has experimented with workplace innovation to foster innovation capabilities in the railway sector, providing elements for companies to remain as innovative and competitive as possible, as well as to have additional tools to adapt to these challenges. In order to help in this process, this article proposes a series of recommendations based on the lessons learnt during the implementation of the project. These recommendations establish a link between policy and workplace innovation practices and could be a reference framework for further research and policy. The suggested policy recommendations are focused on companies and policy makers and are based on the results obtained from the different consultations with the stakeholders involved in this research.

Why Choose the Railway?

Background: The impact of railway suicide in the United Kingdom is extensive, yet reasons for why people choose this method are not clearly understood and research into the examination of suicide notes in this area is limited. Aims: Our study aimed to utilize the unique access to suicide notes written by those who died by suicide on the railway so as to gain a greater understanding of why people chose this method. Method: Descriptive and thematic analysis was conducted on 75 suicide notes for those who had died by suicide on the UK railway between 2010 and 2016. Results: Demographic findings from the sample were largely consistent with railway UK data trends. Five main themes were identified as being significant: "certain and instant," "impersonal and non-human," "ability to be planned," "a good death," and "bereavement suicide." Limitations: Findings are based on suicide note authors who died by suicide on the railway in the UK, as such generalizability may be limited. Conclusion: Findings suggest that people select the railway for their suicide for the following motives: perception of being instant and certain and viewed as a good death, ability to be planned, belief it causes less of a burden on loved ones (via the perception of the railway as impersonal), and a prior experience of it being fatal (via bereavement suicide). Key implications in relation to prevention strategies and future research are discussed.

Ghost trains: Australian rail in the early stages of the global COVID-19 pandemic

The rail industry, as with all sectors worldwide, has faced disruptions due to the global COVID-19 pandemic. This commentary considers how rail organizations in Australia have engaged within the early stages of the crisis, outlining the challenges faced and how they were addressed. Relying on our observations, and anecdotes obtained from others across the Australian rail industry, we identified a range of impacts including determining service delivery levels (and the associated running of "ghost trains"), implementing hygiene measures and social distancing, managing training and medical assessments, and changes in the behavior of passengers and members of the public (including aggression toward staff and increased instances of trespass). Within rail organizations, we saw changes to communication and control structures, new challenges related to balancing priorities (managing risk of rail accidents vs. virus transmission risk), and negative impacts on job design offset by increased informal support for frontline workers. Importantly, from the crisis, we gained new insights about culture. Finally, we provide recommendations regarding how the Human Factors and Ergonomics discipline can support safe and effective rail operations in the context of both widespread crises such as pandemics as well as the less dramatic, but ever present, shifts in the physical, social, economic, and political environments in which rail organizations operate.

A Review on Microstructural Features and Mechanical Properties of Wheels/Rails Cladded by Laser Cladding

The service life of rails would be remarkably reduced owing to the increase of axle load, which can induce the occurrence of damages such as cracks, collapse, fat edges, etc. Laser cladding, which can enhance the mechanical properties of the rail by creating a coating, has received great attention in the area of the rails due to the attractive advantages such as low input heat, small heat-affected zone, and small deformation. In this paper, recent developments in the microstructural characteristics and mechanical properties of a cladded layer on the rail are reviewed. The method of process optimization for enhancing the properties of a cladded layer are discussed. Finally, the trend of future development is forecasted.

The composition and friction-reducing properties of leaf layers

Every autumn rail networks across the world suffer delays, accidents and schedule changes due to low friction problems caused by leaves landing on the rails. These leaves form a layer that can reduce the friction between the wheel and the rail to a similar level as that between ice and an ice-skate ( μ = 0.01 - 0.05 ). Previous works have generated several hypotheses for the chemical reactions and low friction mechanism associated with these layers. In this work, the reaction between an aqueous extract of sycamore leaves and metallic iron is investigated. This reaction has been shown to produce a black precipitate, which matches field observations of leaf layers, while friction tests with these extracts produce characteristic ultra low friction. The reaction is investigated through FTIR, XPS, CHNS and ICP-MS analysis as well as wet chemical testing. The impact of the reaction on friction is investigated through three rounds of tribological testing. The results indicate that the black precipitate produced is iron tannate, formed by complexation of tannins with dissolved iron ions. Friction testing showed that eliminating tannins from the leaf extract resulted in a significant increase in the friction coefficient compared with the control.

Factors deterring and prompting the decision to attempt suicide on the railway networks: findings from 353 online surveys and 34 semi-structured interviews

BACKGROUND

There is a suicide on the British railways every 36 hours. However, the reasons why people choose to die by train are not well understood.AimsTo explore factors influencing and discouraging the decision to attempt suicide on the railway networks.

METHOD

We conducted an online survey and qualitative interviews with individuals who had contemplated or attempted suicide by train.

RESULTS

A total of 353 survey responders had considered and 23 had attempted suicide at rail locations (including railways and metro/underground); a third of these cases were impulsive. The most frequently reported motivations for contemplating or attempting suicide were perceptions of quick and certain lethality (54 and 37%, respectively) and easy access to rail settings (33 and 38%, respectively). The main factor discouraging people from rail suicide was its wider impact, especially on train drivers (19%). In qualitative interviews (N = 34) the desire to avoid intervention from others was also a common motivating factor for attempting suicide on the railway networks.

CONCLUSIONS

People attempt suicide by train because railway settings are easy to access and because of an inaccurate perception of certain and quick lethality. Tackling exaggerated perceptions of lethality may help reduce suicides by train.Declaration of interestNone.

Annoyance in Response to Vibrations from Railways

Rail transport is a key stepping stone in the EU’s transport policy and is pinpointed for investment and growth over the coming decades. This expanding infrastructure implies increased exposure to environmental stressors, such as noise and ground-borne vibrations. Little is known about the health impacts of exposure to these vibrations. The aim of this paper is to examine the association between annoyance from rail vibrations and the distance of residential dwelling from the railway. It reports the first results of a large epidemiological study, EpiVib, which was designed to investigate the long-term health effects of exposure to rail vibrations. The first part of this study examines a self-reported questionnaire. In total, 6894 individuals aged between 18 and 80 living within 1 km of a railway in west Sweden participated. Results presented here examine the association between distance to the railway and annoyance from vibrations and are stratified by train type. A positive association between closer distance and increased annoyance is seen. After adjustment for important modifiers, results showed that vibrations from freight trains and maintenance operations are reported to be moderately and highly annoying at distances of up to 400 m from the railway and diesel up to 300 m. Vibration from passenger and fast trains are significantly annoying up to 200 m from the track. Vibration from freight trains and maintenance operations were considered highly annoying up to 300 m from the track, diesel up to 400 m. Vibration from passenger and fast trains are not reported to be highly annoying after adjustment. Heavier, slower moving locomotives, in the form of diesel and freight trains, appear to be the source of annoyance at distances further from the railway compared to passenger and fast trains. This has implications in terms of property, transport, and infrastructure planning.

Rail-suicide prevention: Systematic literature review of evidence-based activities

BACKGROUND

Rail-related suicide is a relatively rare but extremely lethal method of suicide that can have far-reaching consequences.

OBJECTIVE

The aim of the systematic literature review was to analyze the existing literature on the effectiveness of rail-suicide prevention activities.

DATA SOURCES

Databases used were Scopus, Medline, and ProQuest.

SEARCH TERMS

The search terms used were "suicid*," "prevent*," "rail*," or "train."

ELIGIBILITY CRITERIA

English-language studies published in peer-reviewed journals between 1 January 1990 and 30 April 2015 that presented an overview of rail-related suicide prevention activities and included an analysis of effectiveness were used.

RESULTS

We retrieved 1,229 results in the original search with nine papers presenting empirical evidence. Three studies in the review analyzed the effectiveness of platform screen doors and another three analyzed the installation of blue lights, two papers analyzed the effectiveness of suicide pits, and one included the influence of media reporting guidelines.

CONCLUSION

Platform screen doors, suicide pits, blue lights, and improved media guidelines all have the potential to reduce rail-related suicide events and deaths.

LIMITATIONS

The review was restricted to English-language peer-reviewed papers published within the chosen time period.

Application of Template Matching for Improving Classification of Urban Railroad Point Clouds

This study develops an integrated data-driven and model-driven approach (template matching) that clusters the urban railroad point clouds into three classes of rail track, contact cable, and catenary cable. The employed dataset covers 630 m of the Dutch urban railroad corridors in which there are four rail tracks, two contact cables, and two catenary cables. The dataset includes only geometrical information (three dimensional (3D) coordinates of the points) with no intensity data and no RGB data. The obtained results indicate that all objects of interest are successfully classified at the object level with no false positives and no false negatives. The results also show that an average 97.3% precision and an average 97.7% accuracy at the point cloud level are achieved. The high precision and high accuracy of the rail track classification (both greater than 96%) at the point cloud level stems from the great impact of the employed template matching method on excluding the false positives. The cables also achieve quite high average precision (96.8%) and accuracy (98.4%) due to their high sampling and isolated position in the railroad corridor.

Impact of rail medical standard on obstructive sleep apnoea prevalence

BACKGROUND

The 2004 edition of the National Standard for Health Assessment of Rail Safety Workers (the standard) used the Epworth Sleepiness Scale (ESS) to screen for excessive daytime sleepiness related to obstructive sleep apnoea (OSA). The 2012 edition of the standard expanded the OSA screening matrix to include body mass index, comorbid hypertension and type 2 diabetes as triggers requiring a sleep study to be undertaken irrespective of the ESS.

AIMS

To assess the impact of the new standard on the estimated prevalence of OSA in railway workers.

METHODS

An analysis of data on safety critical employees referred for rail safety health assessment during the 2013 calendar year and meeting the criteria for sleep study referral. Sleep study outcomes were used to assess the predictive value of screening under the new standard.

RESULTS

A total of 200/4311 workers were investigated with a sleep study. One hundred and ninety-three met the new risk factor criteria and 182 (91%) were newly diagnosed with OSA. The prevalence of OSA in the study population was 7%, compared with 2% in 2009. No worker reported an elevated ESS. The false positive to true positive ratio was 0.1 (95% CI 0.06-0.16).

CONCLUSIONS

The new medical standard has resulted in an increased estimate of the prevalence of OSA in rail workers. This study supports the use of objective clinical risk factors to select workers for further investigation, aiming to minimize the risk of accidents associated with excessive daytime sleepiness and other comorbid conditions of OSA.

Investigating the formal countermeasures and informal strategies used to mitigate SPAD risk in train driving

Various countermeasures are used to mitigate signal passed at danger (SPAD) events on railways, yet they continue. While risk factors that destabilise cognitive processes have been identified, less has been published on the relationship between these factors and the informal strategies that drivers themselves adopt to reduce individual SPAD risk. This study aimed to address this gap and used a participative approach to collect and thematically analyse data from 28 drivers across eight rail organisations in Australia and New Zealand. The results showed not all formal countermeasures were considered effective, and identified several informal strategies. These aimed to reduce task disruption, service distortion and maintain connectedness to signals. While some evidenced redundancies in the task and cab, others did not reduce baseline risk. This paper explores the relationship between the established risks and identified strategies towards evaluating the utility of formal and informal mitigations. The research has application to the investigation of collision risk in all transport domains. Practitioner Summary: A participative approach was used to investigate SPAD mitigation techniques in train driving, and to explore risk-strategy relationship dynamics. Several informal strategies designed to reduce task disruption, service distortion and maintain signal connectedness were identified. While some evidenced redundancies in the task and cab, others did not reduce baseline risk.

[Rail plastic surgery technique in the treatment of popliteal contractures]

The case is presented of a patient aged 45 years suffering from thermal burns due to flame following the deflagration of a gas cylinder. The initial lesions involved the four limbs, in particular the knee, and the trunk. The initial taking in charge consisted in an early excision-graft of the limbs. The evolution of the burn was marked by the development of hypertrophic scars at the level of the non-transplanted zones and at the edge of the graft as also by the onset of contractures. Because of the functional problem caused by the contracture as a result of the considerably reduced extension, the patient was admitted for surgical treatment. Thanks to the rail technique described, the patient recovered normal knee function. Post-surgical treatment was straightforward with a hospitalization period of one month. The aesthetic results were satisfactory. The rail technique is part of the therapeutic arsenal for treating knee contractures. Its simplicity, easy technique, and satisfactory results, plus its easy follow-up, make it a highly appreciated technique in the treatment of this type of contracture.