{"title":"CAN WE ASSESS LANDSLIDE HAZARDS IN THE VOLCANIC CRATER OF LAKE ALBANO, ROME, ITALY?","authors":"A. Patera, A. Fabbri","doi":"10.2495/ssr220011","DOIUrl":"https://doi.org/10.2495/ssr220011","url":null,"abstract":"","PeriodicalId":23773,"journal":{"name":"WIT Transactions on the Built Environment","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74277293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Michela Arnoldi, L. Di Landro, G. Janszen, M. Klinger, V. Vinci
Silicone implants are largely used both in aesthetic and reconstructive medicine, thanks to their recognized biocompatibility. The damage of breast prostheses as a consequence of accidental impacts, is however one of the possible critical situations in their use. The behaviour of silicone breast prostheses in case of accidental impacts, for example in a car accident, is studied by experimental crash tests, accounting for the action exerted by seat belts during impact. Possible effects of aging over the mechanical response of the implants are also considered and approached. Static compression tests performed after long term aging indicate a possible degradation of prosthesis mechanical performance, which should be considered when analysing the possible consequences of an accidental damage.
{"title":"SAFETY ASPECTS RELATED TO IMPLANTED BREAST PROSTHESES","authors":"Michela Arnoldi, L. Di Landro, G. Janszen, M. Klinger, V. Vinci","doi":"10.2495/ssr220151","DOIUrl":"https://doi.org/10.2495/ssr220151","url":null,"abstract":"Silicone implants are largely used both in aesthetic and reconstructive medicine, thanks to their recognized biocompatibility. The damage of breast prostheses as a consequence of accidental impacts, is however one of the possible critical situations in their use. The behaviour of silicone breast prostheses in case of accidental impacts, for example in a car accident, is studied by experimental crash tests, accounting for the action exerted by seat belts during impact. Possible effects of aging over the mechanical response of the implants are also considered and approached. Static compression tests performed after long term aging indicate a possible degradation of prosthesis mechanical performance, which should be considered when analysing the possible consequences of an accidental damage.","PeriodicalId":23773,"journal":{"name":"WIT Transactions on the Built Environment","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82355731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Guarascio, A. Libertà, D. Berardi, Emin Alakbarli, M. Lombardi
{"title":"GEOSTATISTICAL MODELING OF SEISMIC ACTIONS ON THE STRUCTURAL COMPONENTS OF THE SAN BENEDETTO ROAD TUNNEL, ITALY","authors":"M. Guarascio, A. Libertà, D. Berardi, Emin Alakbarli, M. Lombardi","doi":"10.2495/ssr220021","DOIUrl":"https://doi.org/10.2495/ssr220021","url":null,"abstract":"","PeriodicalId":23773,"journal":{"name":"WIT Transactions on the Built Environment","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74983157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The purpose of this study is to explore the safety challenges managing shift work in the Swedish forest industry. There are several factors that can affect safety in working life. In general, previous research shows that managerial and leadership behaviours affect safety and well-being regardless of the type of industry. A leadership with a focus on safety affects the safety climate and the outcome in the form of accidents in an organisation. The interaction between managers and employees regarding safety issues also has a positive effect on safety. Leaders who are instead passive regarding safety issues have significant negative effects on safety, contribute to an increased number of accidents and reduce safety-related behaviour in the organisation. This means that employees with passive leaders themselves become less interested in engaging in safety activities. Shift work has also been shown to affect the health and safety of employees. For example, studies show that higher sickness absence is associated with three-shift rotation compared to two-shift rotation and that fatigue and insomnia may be an effect of shift work. Further, research also shows a link between fatigue and a higher frequency of accidents. In this paper, we use a co-creation approach to capture the safety challenges related to shift work. The overall methodological approach in this study is action-oriented research. The empirical data is collected with interviews and focus groups which altogether include 56 respondents with more than 700 years of joint work experiences from shift work in the forest industry. Preliminary results show the importance of creating a safety culture where both the management and the employees take active part and responsibility in solutions. The managers have the formal responsibility, including law and regulation related to safety aspects. The employees in turn have the responsibility for their own choices and behaviours not least related to food, sleep, and training.
{"title":"SAFETY CHALLENGES WHEN MANAGING SHIFT WORK IN THE SWEDISH FOREST INDUSTRY: SOLUTIONS BASED ON MORE THAN 700 YEARS OF WORK EXPERIENCE","authors":"Pia Ulvenblad, H. Barth","doi":"10.2495/ssr220141","DOIUrl":"https://doi.org/10.2495/ssr220141","url":null,"abstract":"The purpose of this study is to explore the safety challenges managing shift work in the Swedish forest industry. There are several factors that can affect safety in working life. In general, previous research shows that managerial and leadership behaviours affect safety and well-being regardless of the type of industry. A leadership with a focus on safety affects the safety climate and the outcome in the form of accidents in an organisation. The interaction between managers and employees regarding safety issues also has a positive effect on safety. Leaders who are instead passive regarding safety issues have significant negative effects on safety, contribute to an increased number of accidents and reduce safety-related behaviour in the organisation. This means that employees with passive leaders themselves become less interested in engaging in safety activities. Shift work has also been shown to affect the health and safety of employees. For example, studies show that higher sickness absence is associated with three-shift rotation compared to two-shift rotation and that fatigue and insomnia may be an effect of shift work. Further, research also shows a link between fatigue and a higher frequency of accidents. In this paper, we use a co-creation approach to capture the safety challenges related to shift work. The overall methodological approach in this study is action-oriented research. The empirical data is collected with interviews and focus groups which altogether include 56 respondents with more than 700 years of joint work experiences from shift work in the forest industry. Preliminary results show the importance of creating a safety culture where both the management and the employees take active part and responsibility in solutions. The managers have the formal responsibility, including law and regulation related to safety aspects. The employees in turn have the responsibility for their own choices and behaviours not least related to food, sleep, and training.","PeriodicalId":23773,"journal":{"name":"WIT Transactions on the Built Environment","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81233790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"PROMOTING SYSTEM SAFETY AND RELIABILITY THROUGH RISK QUANTIFICATION/VISUALISATION METHODOLOGY","authors":"Takafumi Nakamura","doi":"10.2495/ssr220121","DOIUrl":"https://doi.org/10.2495/ssr220121","url":null,"abstract":"","PeriodicalId":23773,"journal":{"name":"WIT Transactions on the Built Environment","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72570563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
César Ricardo Soto-Ocampo, J. Cano-Moreno, J. Mera
The diagnosis of the state of machinery is becoming increasingly important in a more competitive industrial sector. Therefore, maintenance strategies are essential to ensure the correct and continuous operation of equipment. In the last decade, the application of condition based monitoring (CBM) has increased significantly in the detection of bearing faults. CBM is based on the characterisation of equipment behaviour and focuses on preventing a machine from failing. Therefore, fault characterisation and the construction of health indicators is a fundamental issue in CBM. This study evaluates the performance of the diagnostic methodology based on the construction of contour maps from envelope spectra. This allows the construction of visual maps that characterise the evolution of the amplitude of a fault frequency and its harmonics. They also serve as a reference to establish health indicators of future equipment conditions. The results suggest that the methodology holds promise for bearing condition classification. Furthermore, the use of contour maps is a visually intuitive tool for the analyst.
{"title":"CONSTRUCTION OF FAULT EVOLUTION MAPS FOR DAMAGE LEVEL ASSESSMENT OF RAILWAY BEARINGS","authors":"César Ricardo Soto-Ocampo, J. Cano-Moreno, J. Mera","doi":"10.2495/cr220051","DOIUrl":"https://doi.org/10.2495/cr220051","url":null,"abstract":"The diagnosis of the state of machinery is becoming increasingly important in a more competitive industrial sector. Therefore, maintenance strategies are essential to ensure the correct and continuous operation of equipment. In the last decade, the application of condition based monitoring (CBM) has increased significantly in the detection of bearing faults. CBM is based on the characterisation of equipment behaviour and focuses on preventing a machine from failing. Therefore, fault characterisation and the construction of health indicators is a fundamental issue in CBM. This study evaluates the performance of the diagnostic methodology based on the construction of contour maps from envelope spectra. This allows the construction of visual maps that characterise the evolution of the amplitude of a fault frequency and its harmonics. They also serve as a reference to establish health indicators of future equipment conditions. The results suggest that the methodology holds promise for bearing condition classification. Furthermore, the use of contour maps is a visually intuitive tool for the analyst.","PeriodicalId":23773,"journal":{"name":"WIT Transactions on the Built Environment","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82055641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Automatic train operation under the supervision of a human driver is sometimes presented as a first step toward autonomous trains. This paper provides a system analysis of the available norms dealing with automatic train operation under driver supervision. Clarifications that have to be introduced to make it compatible with an autonomous train module are highlighted. Then, the work focuses on the collaboration between an automatic software for braking and accelerating in the European normative and technological context, known as ATO over ETCS. The study of the available documents allows proposing an architectural model of this global system containing on board automation and on track automated specific devices. The main motivation behind using this technical architecture is to trace a future implementation that preserves the high-level goals. This technical contribution is a first step for building an integrated approach to specify a correct system by construction, conforming to the industrial norms of automated train. In this paper, we explain how it is relevant to use a norm based technical architecture, providing intellectual references that allows drivers to identify various functioning phases where, depending on the overall context, they can let an automatic system drive the train or not.
在人类驾驶员监督下的自动列车运行有时被认为是迈向自动列车的第一步。本文对现有的驾驶员监督下列车自动运行规范进行了系统分析。为了使其与自动列车模块兼容，必须进行澄清。然后，工作重点是在欧洲规范和技术背景下的自动制动和加速软件之间的协作，称为ATO over ETCS。通过对现有文件的研究，可以提出一个包含船上自动化和轨道自动化特定设备的全球系统的架构模型。使用此技术体系结构的主要动机是跟踪保留高级目标的未来实现。这一技术贡献是建立一个综合方法的第一步，通过构建指定正确的系统，符合自动化列车的工业规范。在本文中，我们解释了使用基于规范的技术架构是如何相关的，提供了智力参考，允许司机识别各种功能阶段，根据整体环境，他们可以让自动系统驱动火车或不。
{"title":"ATO OVER ETCS: A SYSTEM ANALYSIS FOR FREIGHT TRAINS","authors":"P. Bon, S. Collart-Dutilleul, Racem Bougacha","doi":"10.2495/cr220041","DOIUrl":"https://doi.org/10.2495/cr220041","url":null,"abstract":"Automatic train operation under the supervision of a human driver is sometimes presented as a first step toward autonomous trains. This paper provides a system analysis of the available norms dealing with automatic train operation under driver supervision. Clarifications that have to be introduced to make it compatible with an autonomous train module are highlighted. Then, the work focuses on the collaboration between an automatic software for braking and accelerating in the European normative and technological context, known as ATO over ETCS. The study of the available documents allows proposing an architectural model of this global system containing on board automation and on track automated specific devices. The main motivation behind using this technical architecture is to trace a future implementation that preserves the high-level goals. This technical contribution is a first step for building an integrated approach to specify a correct system by construction, conforming to the industrial norms of automated train. In this paper, we explain how it is relevant to use a norm based technical architecture, providing intellectual references that allows drivers to identify various functioning phases where, depending on the overall context, they can let an automatic system drive the train or not.","PeriodicalId":23773,"journal":{"name":"WIT Transactions on the Built Environment","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86166124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The feeder circuit protection system of the DC substation is protected by the DC overcurrent device, DC fault selective relay and ground fault overvoltage relay. The DC overcurrent device detects an accident when a current exceeds the set value, and the feeder fault selective relay detects a sudden change in the current during the fluctuation time. In addition, the ground fault overvoltage relay detects an accident when the potential between the rail and the ground of the substation mesh earth exceeds the set value and continues for a certain period of time. However, high-resistance ground faults flow only several hundred amperes. Therefore, the high-resistance ground faults cannot be detected by the DC overcurrent device and feeder fault selection relay installed in the substation. In addition, the rail potential is too small to be detected by ground fault overvoltage relay. If the high resistance ground fault continues, the signal equipment will burn out and transport disorder will occur. There was no way to protect the signal equipment room from high-resistance ground faults. Therefore, we have developed a DC ground fault detector with the aim of protecting the signal equipment room from high-resistance ground faults and preventing defect in transport. This time, a field test was conducted to determine the protection set value of the DC ground fault detector and evaluate the weather resistance. In conclusion, it was confirmed that the developed DC ground fault detector for the signal equipment room was no malfunction. Also, considering that the operating voltage of the signal protector operates at 470V DC ± 20%, the major fault setting value was set to 350V DC so that the ground fault current can be cut off due to a serious fault before the protector operates.
{"title":"VERIFICATION OF DC GROUND FAULT DETECTOR FOR THE SIGNAL EQUIPMENT ROOM","authors":"Hideki Nakazawa, Daisuke Takaishi, Takuya Takematsu, Makoto Nezaki, M. Nakayama, Ryuuichi Koma, Masakazu Taguchi","doi":"10.2495/cr220161","DOIUrl":"https://doi.org/10.2495/cr220161","url":null,"abstract":"The feeder circuit protection system of the DC substation is protected by the DC overcurrent device, DC fault selective relay and ground fault overvoltage relay. The DC overcurrent device detects an accident when a current exceeds the set value, and the feeder fault selective relay detects a sudden change in the current during the fluctuation time. In addition, the ground fault overvoltage relay detects an accident when the potential between the rail and the ground of the substation mesh earth exceeds the set value and continues for a certain period of time. However, high-resistance ground faults flow only several hundred amperes. Therefore, the high-resistance ground faults cannot be detected by the DC overcurrent device and feeder fault selection relay installed in the substation. In addition, the rail potential is too small to be detected by ground fault overvoltage relay. If the high resistance ground fault continues, the signal equipment will burn out and transport disorder will occur. There was no way to protect the signal equipment room from high-resistance ground faults. Therefore, we have developed a DC ground fault detector with the aim of protecting the signal equipment room from high-resistance ground faults and preventing defect in transport. This time, a field test was conducted to determine the protection set value of the DC ground fault detector and evaluate the weather resistance. In conclusion, it was confirmed that the developed DC ground fault detector for the signal equipment room was no malfunction. Also, considering that the operating voltage of the signal protector operates at 470V DC ± 20%, the major fault setting value was set to 350V DC so that the ground fault current can be cut off due to a serious fault before the protector operates.","PeriodicalId":23773,"journal":{"name":"WIT Transactions on the Built Environment","volume":"132 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88849673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. V. SILVA E SILVA, Luiz F.V. Corrêa, R. Camporez, C. Scandian, G. D. dos Santos
This work aims to implement and evaluate the effectiveness of the semi-analytical computational method global incremental wear model (GIWM) in predicting the sliding wear of rails in contact with the flange of railway wheels during curves, which is a parameter of great importance for the efficiency of railway operation. The method validation was performed by comparing the wear depth calculated using the GIWM algorithm to the experimental results published in previous work. The data was obtained in dry (relative humidity: 55% ± 10%) pin-on-disc tests carried out on a universal PLINT TE67 tribometer under a normal load of 24.6 N, representing 1.5 GPa of contact pressure. The specimens, hemispherical pins, were extracted from a pearlitic steel rail and the discs were extracted from two different, forged and cast, Class C railway wheels. The tangential sliding speeds were 0.1 m/s and 0.9 m/s, the latter being the most representative according to the literature. The wear model was based on Archard’s law for sliding wear and the algorithm was implemented in Python. The results showed good agreement of the wear depth values between the computational and experimental methods for the cast wheel material under higher sliding speed, partial agreement for both wheel materials at lower speed and inconsistency for the forged wheel material under higher sliding speed. Furthermore, the algorithm is computationally efficient, presenting simulation time up to 180 times less than the finite element methods reported in the literature. Therefore, it was concluded that the GIWM method has potential for application in the freight railway sector, which uses cast wheels extensively, to guide technical areas regarding the wear behavior of rails under sliding contact during curves.
{"title":"COMPUTER SIMULATION TO PREDICT THE SLIDING WEAR OF PEARLITIC RAILS IN CONTACT BETWEEN CAST AND FORGED RAILWAY WHEELS","authors":"J. V. SILVA E SILVA, Luiz F.V. Corrêa, R. Camporez, C. Scandian, G. D. dos Santos","doi":"10.2495/cr220081","DOIUrl":"https://doi.org/10.2495/cr220081","url":null,"abstract":"This work aims to implement and evaluate the effectiveness of the semi-analytical computational method global incremental wear model (GIWM) in predicting the sliding wear of rails in contact with the flange of railway wheels during curves, which is a parameter of great importance for the efficiency of railway operation. The method validation was performed by comparing the wear depth calculated using the GIWM algorithm to the experimental results published in previous work. The data was obtained in dry (relative humidity: 55% ± 10%) pin-on-disc tests carried out on a universal PLINT TE67 tribometer under a normal load of 24.6 N, representing 1.5 GPa of contact pressure. The specimens, hemispherical pins, were extracted from a pearlitic steel rail and the discs were extracted from two different, forged and cast, Class C railway wheels. The tangential sliding speeds were 0.1 m/s and 0.9 m/s, the latter being the most representative according to the literature. The wear model was based on Archard’s law for sliding wear and the algorithm was implemented in Python. The results showed good agreement of the wear depth values between the computational and experimental methods for the cast wheel material under higher sliding speed, partial agreement for both wheel materials at lower speed and inconsistency for the forged wheel material under higher sliding speed. Furthermore, the algorithm is computationally efficient, presenting simulation time up to 180 times less than the finite element methods reported in the literature. Therefore, it was concluded that the GIWM method has potential for application in the freight railway sector, which uses cast wheels extensively, to guide technical areas regarding the wear behavior of rails under sliding contact during curves.","PeriodicalId":23773,"journal":{"name":"WIT Transactions on the Built Environment","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87270612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To analyse a rail network’s punctuality and the operational quality of a timetable on a network-wide scale an advanced simulation is needed. Whereas most simulations use a Monte Carlo approach, we calculate delay distributions analytically and thus need only a single calculation run. Previously we used exponential distribution functions as they map the status in railway operations well and are suited for efficient calculation of delays. The resulting delay distributions due to primary delays along a train’s itinerary as well as delay propagation from other trains is handled by convolution of these distribution functions. However, as the resulting distributions become more complex, a simplification step is needed from time to time to keep calculation times reasonable. Increased requirements for the accuracy of the simulation model and improvements in the computational potential led us to remodel the delays with discrete distributions. This has two main advantages. First, restrictions on the possible form of primary delays are much smaller compared to the previous exponential distributions and second, the simplification step is no longer needed, which increases accuracy considerably. We discuss the different options of distribution modelling and their use in railway applications.
{"title":"IMPROVING RAIL NETWORK SIMULATIONS WITH DISCRETE DISTRIBUTIONS IN ONTIME","authors":"Burkhard Franke, D. Burkolter, B. Seybold","doi":"10.2495/cr220191","DOIUrl":"https://doi.org/10.2495/cr220191","url":null,"abstract":"To analyse a rail network’s punctuality and the operational quality of a timetable on a network-wide scale an advanced simulation is needed. Whereas most simulations use a Monte Carlo approach, we calculate delay distributions analytically and thus need only a single calculation run. Previously we used exponential distribution functions as they map the status in railway operations well and are suited for efficient calculation of delays. The resulting delay distributions due to primary delays along a train’s itinerary as well as delay propagation from other trains is handled by convolution of these distribution functions. However, as the resulting distributions become more complex, a simplification step is needed from time to time to keep calculation times reasonable. Increased requirements for the accuracy of the simulation model and improvements in the computational potential led us to remodel the delays with discrete distributions. This has two main advantages. First, restrictions on the possible form of primary delays are much smaller compared to the previous exponential distributions and second, the simplification step is no longer needed, which increases accuracy considerably. We discuss the different options of distribution modelling and their use in railway applications.","PeriodicalId":23773,"journal":{"name":"WIT Transactions on the Built Environment","volume":"50 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88533107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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