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Minimal utilization rate for railway maintenance windows: a cost-benefit approach
Get PDFMethods for economic assessment are often used in the rail sector to evaluate large infrastructure investments such as new high-speed lines. With larger networks and ageing infrastructure, these methods can also be used for planning maintenance. In this paper, we focus on the newly introduced concept of maintenance windows in Sweden. These are pre-allocated slots in the train timetable dedicated to performing, among others, periodic/frequent maintenance activities. To justify the pre-allocation of such windows, this study presents a method to find minimal utilization rates depending on window designs and traffic situations. Using a cost-benefit approach, the windows are assessed using a total social cost including work costs, loss in traffic production and reliability gains in future traffic. Based on a case study from the Southern main line in Sweden, we study the minimal utilization rate in different test scenarios, i.e., night or day shifts, asset degradation functions and designs of maintenance windows. The results show that lower utilization rates (4-42%) can be accepted during low-volume traffic or for partial closures, while higher utilization rates (47-83%) are required for full closures during high-volume traffic. Whether the rates are measured as the share of used window time or the share of utilized windows is less important, especially when higher utilization is required. Sensitivity analyses of asset knowledge indicate that parameters such as asset degradation function and minimum asset quality (and to a lesser extent traffic volume, discount rate and failure likelihood) can have a substantial effect on the minimum required utilization rates
Identifying MaaS schemes that maximise economic benefits through an economic appraisal
Get PDFMobility-as-a-Service (MaaS) is a new concept of transport mobility where various mobility services such as public transport, taxi and sometimes rideshare services are offered as a bundle with subscription payment. Many government transport agencies, industry bodies and academia have shown interest in MaaS, evidenced by the release of policy papers, trials and academic studies. The trials and studies to date presume that MaaS will benefit society, however, there is a lack of economic justification within the literature on the impacts on users, governments and communities. This paper explores multiple MaaS options through an economic appraisal framework and quantifies the economic benefits of MaaS. The economic appraisal framework monetised the MaaS impacts that were identified in past literature and compared the net benefits to society of several MaaS options developed for this paper. The appraisal demonstrated that the MaaS option that promotes public and active travel generates the largest economic benefits compared to other options that were considered. This paper demonstrates that transport policy can be developed based on the net impacts MaaS can provide to society. It also contributes to the discussion on policy issues surrounding MaaS which is important as government transport agencies and industry partners explore the justification for investment and implementation requirements
Investigating Wave Transmission through Curtain Wall Breakwaters under Variable Conditions
Get PDFCoastal erosion has become a pressing problem all over the world, especially in areas where the hinterland is only slightly elevated over the sea level. The ongoing progression reveals the urging need for engineered coastal protection measures like breakwaters. Amongst others, curtain wall breakwater types (CWB) have proven their potential to dissipate the wave energy in multiple studies. Their application is often considered in situations where only a partial protection of the coast is needed (e.g. to maintain a hydraulic connectivity or enable sediment transport for land reclamation). Due to their slender design, they are assumed to offer an economical alternative in comparison to massive breakwater constructions, while their pillar-based foundation shows advantages for applications under soft soil conditions. Within the development process of a detached breakwater to face coastal erosion in the Mekong Delta, different types of CWB configurations have been investigated under regular wave conditions. Several characteristics of CWB structures such as the inclination and thickness of the wall, the height of the structures, the rate of submergence and emergence were examined for different water depths and wave parameters. The wave-structure interaction was analyzed using FLOW3D software, which is capable of simulating wave transformation. It showed a high agreement in comparison with own experimental investigations and the wave theory. The results showed a continuous reduction of the wave transmission coefficient with increasing inclination from 90° to 135°, whilst the orientation of the inclination (e.g. 60° vs 120°) only showed a minor effect regarding the wave reduction. All CWB arrangements showed increasing performance with decreasing wave periods. Besides, the wave transmission was mainly impacted by the level of submergence together with the amount of supporting piers and the thickness of the structures. Water depth changes due to tidal influence revealed an increase in wave transmission coefficient once the wave started to overtop the structure
Analytical Models for Determining the Propagation of Rectangular Surface Jets for Fishway Attraction Flow
Get PDFThe present paper evaluates suitability of two analytical models to determine the propagation of rectangular surface jets as a tool to design fishway attraction flow. It focuses on rectangular orifices of vertical slot fishways with aspect ratios (width-to-height) for W/H < 1. Both models were rewritten to match boundary conditions for fishways because they were initially derived for horizontal orifices. As the basis for the evaluation, the output of the analytical models to RANS simulations for 12 geometries 1/16 <= W/H <= 4 is compared. Applied analytical equations for half-lengths for cases W/H >= 4 are within 5 % of RANS modeling results for all cases. The location of centerline transition locations from analytical models also agree reasonably well with RANS modeling. The findings support efficient design of optimum attraction flow propagation using simple, rapid analytical approaches
Stimulating Education about Standardization – Activities and perspectives of National Standards Bodies
Get PDFStandardization is essential for business and society. However, many people remain unaware of this. Education about Standardization (EaS) would be one solution to increase awareness. EaS has been a topic of research for several decades. Literature suggests that National Standards Bodies (NSBs) can play a core role in stimulating EaS – but is this actually the case? This research aims to investigate what NSBs do in stimulating EaS and hear their perspectives on EaS. Based on the literature and insights from experts in the field, a survey was prepared and sent to NSBs. Next, stories behind the data were revealed during in-depth interviews with NSB experts. The results from 90 NSBs all over the world show that they believe there is a need for EaS and most of them have activities in this field. They also share insights about what should be achieved in the following years, potential solutions to reach their objectives, and the future of EaS. This article advances knowledge in the field of EaS, with a focus on the role, actions, and perspectives of NSBs. This work also provides suggestions on how NSBs can foster EaS together with other stakeholders. This is one of the first studies with a focus on NSBs in fostering EaS
General Court EU: Commercial interests block the right to access European harmonised standards
Get PDFThe submitted contribution is a case note, so there is no abstract available
An Analysis of Trip Preferences among E-bike Users in Commuting: Evidence from an Online Choice-based Conjoint Experiment
Get PDFThe present study reports on the preferences among e-bike users for commuting trips. An online survey with sixteen choice-based conjoint questions was conducted in March 2020 amongst 144 e-cyclists and non e-cyclists in Flanders (Belgium). Their choices were analysed using a no-choice binomial logit model. The impact of the following factors showed to be most important: weather conditions, trip time, type of e-bike, and financial support by the employer. The effect on e-bike users of factors such as cycling infrastructure, secure parking, and shower facilities at the workplace seems more limited. Based on the difference between male and female respondents, trip time and type of e-bike differed significantly. The only significant difference between e-bike owners and non e-bike owners was the type of e-bike. Trip time, weather conditions and financial intervention differed significantly between the young and old age group. Our findings suggest that policymakers should focus on investments in e-bikes, such as cycling infrastructure, mileage allowance and facilities at the workplace to make this a sustainable and socially inclusive mode of transport
Narrative Deserts and Embodied Meanings in the City : The Microstories of Ghent’s City Pavilion
Get PDFIn his famous analysis of everyday life, Michel de Certeau examines how the technocratic discourse of production and consumption deprives urban inhabitants of meaningful stories. At the same time, he discerns a proliferation of microstories that resist this homogenization. We want to argue that de Certeau’s work is still very relevant for a discussion about meaningfulness and the contemporary city, if we take into account that these stories can also be antagonistic and even destructive. Following the work of Mark Johnson, we also would like to regard meaning as something that is not only linguistic, but emerges from an affective, sensorial interaction with our built environment. As a case study, we will discuss Ghent’s City Pavilion, designed by Robbrecht & Daem and Marie-José Van Hee architects, as a generator of stories and embodied meanings, both positive and negative.
The Concept of Appropriation in Collective Housing Design : Understanding Dwelling as a Poetic Practice
Get PDFThe article aims to contribute to the theoretical debate on collective housing design by focusing on dwelling as a poetic practice. More precisely, it explores the methodological potential of the concept of appropriation that fosters the understanding of dwelling as the creative practice of human self-realization through space. It does so by interpreting selected writings of Henri Lefebvre and bringing forward exemplary housing projects. The theoretical review concludes with several principles of housing design that underline the importance of the continuity, overlapping and ‘softness’ of dwelling space. Moreover, the article conceptualizes appropriation as an analytical tool for reading the transformation of existing space made by residents. Appropriation narratives, in this way, enable housing design to understand and consider the spatial characteristics that contribute to meaningful emotional connections between space and people on different scales