| 1. |
- Ait Ali, Abderrahman, 1991-, et al.
(författare)
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Assessing Innovations in High-Speed Rail Infrastructure
- 2023
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Ingår i: Socioeconomic Impacts of High-Speed Rail Systems - Proceedings of the 2nd International Workshop on High-Speed Rail Socioeconomic Impacts, IW-HSR 2022. - Stockholm : Springer Nature. ; , s. 217-233, s. 217-233
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Konferensbidrag (refereegranskat)abstract
- Innovations in high-speed rail (HSR) have had substantial effects on different stakeholders within and outside the railway system. As part of the European Shift2Rail research programme, several innovative solutions are developed for, among others, improving the HSR infrastructure. The Joint Undertaking behind this research program has set objectives for these innovations in terms of punctuality, capacity, and life cycle costs. With a focus on infrastructure-related innovations for HSR, this paper aims at assessing their impacts in relation to these targets. We review the relevant research literature about the effects of HSR innovations and their assessment. The paper presents a hybrid assessment methodology combing different approaches to assess capacity, punctuality, and cost effects. This contributes to reducing the existing gap that is found in the research literature. Based on a reference scenario for HSR line and collected data from different stakeholders, the results indicate that infrastructure innovations in HSR, being developed within the European Shift2Rail research programme, can contribute to reaching the target set for punctuality. Further innovations in HSR infrastructure and/or other railway assets may be needed to reach additional targets and for more accurate improvement values giving more insights into their impacts.
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| 2. |
- Ait-Ali, Abderrahman, 1991-, et al.
(författare)
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Evaluating the mix of maintenance activities on railway crossings with respect to life-cycle costs
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Switches & crossings (S&Cs) are vital assets as they allow for increased railway capacity by introducing flexibility and connectivity in railway networks. At the same time, this makes them critical since they can cause costly delays and disruptions if they are not well maintained. This motivates studies to improve maintenance strategies of S&Cs, considering both the life-cycle costs (LCC) of the assets and socio-economic transportation costs for passengers and freight customers. In this paper, the interdependence between deterioration mechanisms, maintenance activities, and expected LCC (including transportation costs) is investigated using a combination of mechanical and econometric modelling. The interrelation between the degradation of contact geometry and track settlement is analysed using simulations of dynamic vehicle–turnout interaction. Long-term mechanical degradation of the S&C is simulated for different maintenance strategies that correspond to different timing of the associated maintenance measures (crossing repair welding and tamping). This provides the basis for analysing the interdependence between preventive and corrective activities using econometric modelling. Based on a case study of a common type of S&Cs in the Swedish infrastructure, the impact of different maintenance strategies on LCC and transportation costs is analysed. Opportunities and challenges in the development of more socio-economically effective maintenance strategies of S&Cs are discussed.
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| 3. |
- Ait Ali, Abderrahman, 1991-, et al.
(författare)
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Evaluating the mix of maintenance activities on railway crossings with respect to life-cycle costs
- 2024
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Ingår i: European Journal of Transport and Infrastructure Research. - : TU Delft. - 1567-7141 .- 1567-7133. ; 24:1, s. 1-29
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Tidskriftsartikel (refereegranskat)abstract
- Switches & crossings (S&Cs) are vital assets as they allow for increased railway capacity by introducing flexibility and connectivity in railway networks. At the same time, this makes them critical since they can cause costly delays and disruptions if they are not well maintained. This motivates studies to improve maintenance strategies of S&Cs, considering both the life-cycle costs (LCCs) of the assets and socio-economic transportation costs for passengers and freight customers. In this paper, the interdependence between deterioration mechanisms, maintenance activities, and expected LCC (including transportation costs) for the crossing panel – an S&C subsystem – is investigated using a combination of mechanical and econometric modelling. The interrelation between the degradation of contact geometry and track settlement is analysed using simulations of dynamic vehicle– turnout interaction. Long-term mechanical degradation of the crossing panel is simulated for different maintenance strategies that correspond to different timing of the associated maintenance measures (crossing repair welding and tamping). This provides the basis for analysing the interdependence between preventive and corrective activities using econometric modelling. Based on a case study of a common type of S&Cs in the Swedish infrastructure, the impact of different maintenance strategies on LCC and transportation costs is analysed. Opportunities and challenges in the development of more economically effective maintenance strategies of S&Cs are discussed.
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| 4. |
- Ait-Ali, Abderrahman, 1991-, et al.
(författare)
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Evaluating the mix of maintenance activities on railway crossings with respect to life-cycle costs
- 2024
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Ingår i: Sammanställning av referat från Transportforum 2024. - Linköping : Statens väg- och transportforskningsinstitut. ; , s. 405-406
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Switches and crossings (S&Cs) are critical assets in the Swedish rail infrastructure, with a density of 0.8 S&C per track-km and renewal costs of up to 4.5 million SEK/S&C. The efficiency of maintenance strategies for S&Cs is vital from a (socio-)economic perspective. The focus of this study is on the importance of the mix of maintenance activities performed on a S&C with respect to its life-cycle costs (LCCs). The study investigates the interdependencies between the deterioration mechanisms, preventive and corrective maintenance activities, and expected LCCs, including transportation costs due to traffic disruptions/delays. One or a combination of different approaches are often used in the literature, such as engineering or LCC methods. In this research, a novel approach is introduced that combines mechanical simulations, data analysis, econometrics, and LCC calculations to compare the efficiency of different maintenance strategies. The mechanical simulations consider one S&C on the Swedish railway network. The selection criteria were that the S&C is located on the main line, installed in 2014 (generates the longest observation period given the availability of data), and had no extreme values with respect traffic volume, maintenance activities and failures. The interrelation between the degradation of contact geometry and track settlement is analysed using simulations of dynamic vehicle–turnout interaction. Further, the relationship between frequency of preventive and occurrence of corrective maintenance activities is analyses using an econometric model. Implications of a specific mix of maintenance activities on the S&C lifetime and LCC are evaluated using different cost parameters. Results obtained from mechanical simulations reveal the correlation between poor crossing geometry and higher rates of ballast settlement. The econometric analysis finds a statistically significant impact of (cumulative) preventive maintenance on corrective maintenance, i.e., more preventive maintenance leads to fewer corrective activities. Based on a standard mix of maintenance activities (inferred using econometric regression across all S&Cs), the lifetime of the selected S&C is estimated to 10 years with a lower associated LCC than that resulting from the record of performed maintenance activities at the site. The LCC evaluations highlight the potential to improve the efficiency of S&C maintenance by adopting proactive strategies.
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| 5. |
- Ait-Ali, Abderrahman, 1991-, et al.
(författare)
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Evaluation of long-term maintenance of switches & crossings with respect to life-cycle costs and socio-economic impact
- 2022
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Switches & crossings (S&Cs) are vital assets as they allow for increased railway capacity by introducing flexibility and connectivity in railway networks. At the same time this makes them critical, and they can cause major delays and disruptions if they are not well maintained. This motivates studies to improve maintenance strategies of S&Cs, considering both life-cycle costs (LCC) of the assets and other additional socio-economic costs (e.g., transportation costs for passengers and freight customers). In this paper, the interdependence between deterioration mechanisms, maintenance activities, and expected LCC (including transportation costs) is investigated using a combination of mechanical and econometric modelling.The interrelation between the degradation of contact geometry and track settlement is analysed using simulations of dynamic vehicle–turnout interaction. Changes in the timing of the associated maintenance measures (crossing repair welding and tamping) are performed to investigate the impact on damage modes. This is then linked to LCC and transportation costs, which requires a distribution between preventive and corrective activities with respect to the simulated maintenance strategy. This relationship is investigated by means of regression modelling: ??????????=?(??????????,?)where Corrective and Preventive represent the number of failures and the scheduled actions to prevent these failures, respectively. ? holds variables related to the traffic (volume, type of traffic, axle load, etc.) and the infrastructure (type of S&Cs, etc.).
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| 6. |
- Andersson, Mats, et al.
(författare)
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Strategi för utveckling av en samhällsekonomisk analysmodell för drift, underhåll och reinvestering av väg- och järnvägsinfrastruktur
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Möjligheten att fatta beslut om behovet av anslagsmedel till drift, underhåll och reinvestering av vägaroch järnvägar baserat på ett väl strukturerat underlag är idag små. Detta skapar betydande risker attmedel används på ett samhällsekonomiskt ineffektivt sätt. För att Trafikverket ska kunna genomföradenna verksamhet så att sannolikheten att medlen används på rätt sätt ökar krävs därför en utveckling avett transparent beslutstöd.VTI redovisar i föreliggande rapport en kartläggning av kunskapsläget inom de olika delområden därkunskaper krävs för att få till stånd en samhällsekonomisk analys av drift, underhåll och reinvestering.Vår bedömning är att det idag inte finns modellverktyg som gör det möjligt att utan vidare genomförasådana analyser. Samtidigt visar genomgången att det finns goda förutsättningar att redan inom relativtkort tid ta fram ett underlag som gör det möjligt att besvara åtminstone delar av de frågeställningar somformulerats. Genomgången pekar således på att det finns stora möjligheter att flytta fram positionernabåde inom väg- och järnvägsområdet. Fem specifika projekt har utformats varav tre avser insatser på kortsikt och två på lång sikt. Målsättningen på lång sikt är att kunna göra en bedömning av vilkenkostnadsvolym och tillståndsnivå som behövs utifrån ett samhällsekonomiskt perspektiv på olika vägaroch järnvägar.
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| 7. |
- Björklund, Gunilla, 1973-, et al.
(författare)
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Fotgängares värderingar av gångvägar
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Bakgrunden till den här studien är en förfrågan från Trafikverket att ta fram ett samhällsekonomiskt underlag för fotgängares värderingar av deras gångmiljö och hur olika åtgärder påverkar besluten att gå. De frågeställningar som forskarna undersökte var: 1. Vilken typ av väg föredrar fotgängare när de väljer väg? 2. Vad är betalningsviljan för att få mer attraktiva gångvägar? 3. Hur många kommer börja gå om det byggs mer attraktiva gångvägar? Den tredje frågeställningen var dock inte möjlig att besvara på grund av för låg svarsfrekvens i den delstudien. Resultatet från studien visar att individer inte verkar föredra separerade gång- och cykelbanor eller helt avskilda gångbanor i den utsträckning man kanske kan förvänta sig. Huvudsaken verkar vara att promenaden sker på en gångbana av något slag, och inte längs vägkanten på en väg med motorfordon. Sikten verkar ha stor betydelse för vilken väg personer väljer att gå. Övriga gångvägsattribut som underhåll, avstånd till väg med motorfordon och typ av korsning hade inte alls lika stor betydelse. Forskarna konstaterar att intresset för fotgängarfrågor inte är så stort. Respondenterna verkade också ha svårigheter med att svara på flera av frågorna och i fortsatta studier kring fotgängares värderingar rekommenderas därför att undersökningarna genomförs i någon typ av intervjuform eftersom det då är lättare att förtydliga oklarheter.
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| 8. |
- Charoenwong, C., et al.
(författare)
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The effect of rolling stock characteristics on differential railway track settlement : An engineering-economic model
- 2022
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Ingår i: Transportation Geotechnics. - : Elsevier Ltd. - 2214-3912. ; 37
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Tidskriftsartikel (refereegranskat)abstract
- Railway track geometry deteriorates under repeated train loading. When linespeed is increased or new rolling-stock is introduced this can alter the future rate of change of differential settlement and track geometry. Therefore this paper presents a novel combined engineering-economic approach to investigate the effect of increasing train speeds, adding additional passenger movements, and adding additional freight movements to an existing line. Firstly a numerical algorithm is presented to compute differential track settlement. An important novelty of the model is its use of the wavenumber finite element method coupled with settlement relationships in a manner that allows for track irregularities to evolve after every load passage (i.e. taking into account the evolution of the track unevenness profile before applying each subsequent train passage). Unlike traditional approaches this allows the model to faithfully simulate mixed traffic conditions, including the coupled interactions between different rolling stock types and track geometry. The engineering model is used to predict tamping intervals, and then coupled with an economic model capable of calculating deterioration elasticities and marginal costs. It is shown that higher speeds result in higher dynamic forces and cause a faster rate of deterioration of track geometry, thus increasing marginal cost. The model is then used to investigate the effect of adding additional train movements to a passenger line. It is shown that additional movements increase the rate of track degradation and marginal costs, particularly if the additional traffic is freight. This is because freight vehicles typically have one only layer of (stiff) suspension, thus generating elevated dynamic forces compared to passenger vehicles. © 2022
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| 9. |
- Forsman, Åsa, 1972-, et al.
(författare)
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Effektutvärdering av stängsling på järnväg : Pilotprojekt i Region Öst
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Trafikverket har under 2010-talet arbetat med en åtgärdsstrategi inom järnvägen som bland annat inneburit att nya stängsel har satts upp längs spåren på utpekade sträckor. Syftet med dessa åtgärder har varit att minska antal personpåkörningar i enlighet med halveringsmålet som innebär högst 55 omkomma i järnvägstransportsystemet år 2020. Det har dock inte genomförts någon mer omfattande utvärdering av stängslingens effekt, delvis på grund av de svårigheter detta innebär. Syftet med den här studien var att analysera stängslingens effekter i Trafikverkets region Öst och, baserat på dessa erfarenheter, bedöma om metoden kan användas nationellt. En viktig del i projektet var att bedöma om de dataunderlag som finns är av tillräckligt bra kvalitet för att en nationell utvärdering ska vara rimlig att genomföra.
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| 10. |
- Hossein Nia, Saeed, 1983-, et al.
(författare)
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Simulation-based evaluation of maintenance strategies from a life cycle cost perspective
- 2023
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Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. - 9780646865881 ; 532-533, s. 258-265
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Tidskriftsartikel (refereegranskat)abstract
- A methodology that combines simulations of long-term mechanical degradation including maintenance interventions with an assessment of the associated socio-economic impact is proposed. This development responds to an urgent need within the railway sector to enable the evaluation of maintenance strategies from a LCC perspective. The functionality of the methodology is demonstrated in an investigation of rail grinding strategies for a curve on the Swedish Iron-ore line. The results indicate a reduction in LCC of 50% when using a harder rail material (R400HT) combined with annual rail grinding as compared to a softer rail material (R350LHT) and two grinding campaigns per year.
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