| 1. |
- Andersson-Sköld, Yvonne, 1957-, et al.
(författare)
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Ramverk för att prioritera och bedöma nyttan av klimatanpassningsåtgärder
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Klimatförändringarna är idag påtagliga och även om vi snabbt får ner utsläppen av växthusgaser kommer fler, mer omfattande och mer kostsamma klimatrelaterade händelser att inträffa alltmer ofta. Kostnaderna inom den svenska transportsektorn för klimatrelaterade händelser som skadar gator, vägar, spår-/järnväg, med flera sårbara delar av infrastrukturen är stora redan idag och förväntas öka. Översvämningar, bränder och skador till följd av väderrelaterade händelser på anläggningar resulterar bland annat i minskad framkomlighet och en ökad risk för olyckor. För att upprätthålla transportsystemets funktion är det därför viktigt att vi vidtar riskreducerande åtgärder för att minska sannolikheten och omfattningen av negativa konsekvenser av både dagens klimat- och väderrelaterade händelser men framför allt för att hantera framtida klimatrelaterade händelser. Det är nödvändigt att säkerställa transportsystemets funktion vid extrema väderhändelser, och under perioder av långvarig nederbörd, långvariga värmeböljor och förändrade nederbördsmönster. Det gäller också att redan idag möjliggöra anpassningsåtgärder för att hantera långsiktiga förändringar som höjd havsvattennivå och grundvattennivåer, som påverkar infrastrukturens framkomlighet och livslängd.I denna rapport presenteras sammanfattande resultat och en sammanfattning av hur ett ramverk för att utvärdera klimatrelaterade effektsamband har använts. Med effektsamband avses att identifiera, bedöma och värdera klimatrelaterade risker och riskreducerande åtgärder. I denna rapport är fokus på att identifiera, bedöma och utvärdera effektiviteten av klimatrelaterade åtgärder. Resultatet av det framtagna ramverket kan användas för att analysera riskreducerande åtgärders effekter, det vill säga för att bedöma om det är relevant att genomföra en åtgärd, när i tiden den bör genomföras samt för att bedöma vilken åtgärd som är mest relevant att genomföra. De risker som beaktas genom fallstudier innefattar brandrisk, olycksrisk på gator och vägar på grund av nollgenomgångar eller värme, översvämning, erosion och skred och påverkan på vägkonstruktionen (spårbildning, bärighet och utmattning), solkurvor och risker vid kraftiga vindar. Testerna har innefattat faro- och riskidentifiering, riskanalys, identifiering och utvärdering av möjliga åtgärder. Exempel på fallstudier är Gävleregnet 2021, ett skyfall i Kungsbacka kommun 2019, erosionsrelaterade förändringar under lång tid vid Österdalälven och beräkningar av påverkan av temperatur, fuktighet och förändringar i tjälförändringsmönster på vägkonstruktionen vid E10 vid Svappavaara. I en av de fallstudier som sammanfattas i rapporten redovisas även en monetär värdering och känslighetsanalys. Ramverket har också legat till grund för en diskussion avseende klimatrelaterade risker kopplade till elförsörjning.
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| 2. |
- Carlberger, Andreas, 1992, et al.
(författare)
-
Numerical prediction of rail corrugation growth on curves
- 2016
-
Ingår i: Proceedings of the 19h Nordic Seminar on Railway Technology, September 14 - 15, Luleå, Sweden (2016).
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Rail corrugation (periodic surface irregularities at distinct wavelengths) is a problem experienced by many railway networks worldwide. Corrugation induces a pronounced dynamic wheel‒rail contact loading that leads to increased generation of noise and in severe cases even damage to vehicle and track components. The large magnitude creep forces and sliding between wheel and rail make corrugation especially prone to develop on curved track. The current work summarizes the results from a Master Thesis project performed in collaboration between Chalmers, ÅF Industry, Bombardier Transportation and Stockholm Public Transport. A time-domain model for the prediction of long-term growth of rail roughness has been developed, see Figure 1. Dynamic vehicle‒track interaction in a broad frequency range (at least up to 300 Hz) is simulated using the commercial software SIMPACK. Wheelset structural flexibility is accounted for by using modal parameters calculated for a finite element model. Non-Hertzian and non-steady wheel‒rail contact and associated generation of wear are calculated in a post-processing step in the software Matlab. Archard’s law is applied to model the sliding wear. A large number of train passages is accounted for by recurrent updating of the rail surface irregularity based on the calculated wear depth. The proposed prediction model is applied to investigate a curve on the Stockholm metro network exposed to severe corrugation growth.
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| 3. |
- Nielsen, Jens, 1963, et al.
(författare)
-
Switch panel design based on simulation of accumulated rail damage in a railway turnout
- 2016
-
Ingår i: Wear. - : Elsevier BV. - 0043-1648. ; 366-367:SI, s. 241-248
-
Tidskriftsartikel (refereegranskat)abstract
- A methodology for numerical prediction of accumulated rail damage in railway turnouts is presented. Based on simulation of dynamic vehicle-track interaction followed by a discretisation of the conditions in each wheel-rail contact, distributions of rail wear are calculated by the Archard model of sliding wear, while surface initiated rolling contact fatigue (RCF) damage is evaluated by the Palmgren–Miner rule and an index building on shakedown theory. Partial slip in the wheel-rail contacts and variable amplitude loading are considered. For freight traffic in the diverging route, the influence of rail inclination and switch rail elevation on damage in the switch panel is investigated in a demonstration example. Two-point contact situations with one contact on the switch rail and one on top of the stock rail induce relative motion and slip between wheel and rail leading to high energy dissipation. In agreement with field observations, it is concluded that wear is the dominating damage mechanism on the gauge side of the switch rail while the risk for RCF is higher on the crowns of the switch and stock rails. For accurate prediction of rail life for given combinations of wheel/rail materials and traffic conditions, the methodology needs to be calibrated by field measurements.
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| 4. |
- Nielsen, Jens, 1963, et al.
(författare)
-
Switch panel design based on simulation of accumulated rail damage in a railway turnout
- 2015
-
Ingår i: Proceedings of the 10th International International Conference on Contact Mechanics and Wear of Rail/Wheel Systems, Colorado Springs, USA, August-September 2015.
-
Konferensbidrag (refereegranskat)abstract
- A methodology for numerical prediction of accumulated rail damage in railway turnouts is presented. Based onsimulation of dynamic vehicle‒track interaction followed by a discretisation of the conditions in each wheel‒railcontact, distributions of rail wear are calculated by the Archard model of sliding wear, while surface initiated rollingcontact fatigue (RCF) damage is evaluated by the Palmgren-Miner rule and an index building on shakedown theory.Partial slip in the wheel‒rail contacts and variable amplitude loading are considered. For freight traffic in the divergingroute, the influence of rail inclination and switch rail height on damage in the switch panel is investigated in ademonstration example. Two-point contact situations with one contact on the switch rail and one on top of the stock rail induce relative motion and slip between wheel and rail leading to high energy dissipation. In agreement with fieldobservations, it is concluded that wear is the dominating damage mechanism on the gauge side of the switch rail whilethe risk for RCF is higher on the crowns of the switch and stock rails. For accurate prediction of rail life for givencombinations of wheel/rail materials and traffic conditions, the methodology needs to be calibrated by fieldmeasurements.
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| 5. |
- Torstensson, Peter, 1981-, et al.
(författare)
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Wheel–rail impact loads and noise generated at railway crossings : Influence of vehicle speed and crossing dip angle
- 2019
-
Ingår i: Journal of Sound and Vibration. - : Academic Press. - 0022-460X .- 1095-8568. ; 456, s. 119-136
-
Tidskriftsartikel (refereegranskat)abstract
- Wheel–rail impact loads and noise at railway crossings are calculated by applying a hybrid prediction model. It combines the simulation of non-linear vertical dynamic vehicle‒track interaction in the time domain and the prediction of sound pressure level using a linear frequency-domain model. The two models are coupled based on the concept of an equivalent roughness spectrum. The time-domain model uses moving Green's functions for the linear vehicle and track models, accounting for wheel structural flexibility and a discretely supported rail with spatially-varying beam properties, and a non-Hertzian wheel–rail contact model. Three-dimensional surface geometry of the wheel and crossing is accounted for in the solution of the wheel–rail contact. The hybrid model is compared against field measurements and is demonstrated by investigating the influence of vehicle speed and crossing geometry on the radiated impact noise. Based on simulation results, it is concluded that the impact loads and noise can be mitigated by reducing the effective dip angle at the crossing, which is determined by the vertical trajectory of the wheel when making the transition between wing rail and crossing nose.
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| 6. |
- Ait Ali, Abderrahman, 1991-, et al.
(författare)
-
Evaluating the mix of maintenance activities on railway crossings with respect to life-cycle costs
- 2023
-
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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| 7. |
- Ait Ali, Abderrahman, 1991-, et al.
(författare)
-
Evaluating the mix of maintenance activities on railway crossings with respect to life-cycle costs
- 2024
-
Ingår i: Sammanställning av referat från Transportforum 2024. - Linköping : Statens väg- och transportforskningsinstitut. ; , s. 405-406
-
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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| 8. |
- Ait Ali, Abderrahman, 1991-, et al.
(författare)
-
Evaluation of long-term maintenance of switches & crossings with respect to life-cycle costs and socio-economic impact
- 2022
-
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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| 9. |
- Andersson, Robin, 1986, et al.
(författare)
-
An efficient approach to the analysis of rail surface irregularities accounting for dynamic train–track interaction and inelastic deformations
- 2015
-
Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 1744-5159 .- 0042-3114. ; 53:11, s. 1667-1685
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Tidskriftsartikel (refereegranskat)abstract
- A two-dimensional computational model for assessment of rolling contact fatigue induced by discrete rail surface irregularities, especially in the context of so-called squats, is presented. Dynamic excitation in a wide frequency range is considered in computationally efficient time-domain simulations of high-frequency dynamic vehicle-track interaction accounting for transient non-Hertzian wheel–rail contact. Results from dynamic simulations are mapped onto a finite element model to resolve the cyclic, elastoplastic stress response in the rail. Ratcheting under multiple wheel passages is quantified. In addition, low cycle fatigue impact is quantified using the Jiang–Sehitoglu fatigue parameter. The functionality of the model is demonstrated by numerical examples.
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| 10. |
- Andersson, Robin, 1986, et al.
(författare)
-
Integrated analysis of dynamic vehicle-track interaction and plasticity induced damage in the presence of squat defects
- 2015
-
Ingår i: Proceedings of the 10th International International Conference on Contact Mechanics and Wear of Rail/Wheel Systems, Colorado Springs, USA, August-September 2015.
-
Konferensbidrag (refereegranskat)abstract
- Despite significant efforts, the mechanisms behind the formation of squats – a form of rolling contact fatigue damage – are not fully understood. This study employs numerical simulations to investigate the propensity of squat initiation in the vicinity of small, isolated rail surface irregularities. Time domain dynamic vehicle–track interaction analysis is used to obtain wheel–rail contact stress distributions, which are mapped onto a continuum finite element model that accounts for plastic deformation of the rail material. The evaluated stress and strain fields are quantified using two RCF impact measures: accumulated effective strain and the Jiang-Sehitoglu multiaxial low cycle fatigue parameter. It is shown that the RCF impact increases with increasing size of the surface irregularity and that clustering of irregularities might strongly promote RCF. The friction coefficient is identified as a very influential parameter. Further, the effect of variations in friction along the rail is evaluated. It is shown that a short rail section of low friction results in fairly high RCF impact.
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| 11. |
- Andersson, Robin, 1986, et al.
(författare)
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Integrated analysis of dynamic vehicle–track interaction and plasticity induced damage in the presence of squat defects
- 2016
-
Ingår i: Wear. - : Elsevier BV. - 0043-1648. ; 366-367:SI, s. 139-145
-
Tidskriftsartikel (refereegranskat)abstract
- Despite significant efforts, the mechanisms behind the formation of squats – a form of rolling contact fatigue (RCF) damage – are not fully understood. This study employs numerical simulations to investigate the propensity of squat initiation in the vicinity of small, isolated rail surface irregularities. Time-domain dynamic vehicle–track interaction analysis is used to obtain wheel–rail contact stress distributions, which are mapped onto a continuum finite element model that accounts for plastic deformation of the rail material. The evaluated stress and strain fields are quantified using two RCF impact measures: accumulated effective strain and the Jiang–Sehitoglu multiaxial low cycle fatigue parameter. It is shown that the RCF impact increases with increasing size of the surface irregularity and that clustering of irregularities might strongly promote RCF. The friction coefficient is identified as a very influential parameter and also the effect of variations in friction along the rail is evaluated.
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| 12. |
- Andersson, Robin, 1986, et al.
(författare)
-
The influence of rail surface irregularities on contact forces and local stresses
- 2015
-
Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 1744-5159 .- 0042-3114. ; 53:1, s. 68-87
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of initial rail surface irregularities on promoting further surface degradation is investi-gated. The study concerns rolling contact fatigue formation, in particular in the form of the so-calledsquats. The impact of surface irregularities in the form of dimples is quantified by peak magnitudesof dynamic contact stresses and contact forces. To this end simulations of two-dimensional (laterextended to three-dimensional) vertical dynamic vehicle–track interaction are employed. The mostinfluencing parameters are identified. It is shown that even very shallow dimples might have a largeimpact on local contact stresses. Peak magnitudes of contact forces and stresses due to the influenceof rail dimples are shown to exceed those due to rail corrugation.
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| 13. |
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| 14. |
- Brouzoulis, Jim, 1984, et al.
(författare)
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Prediction of Wear and Plastic Flow in Rails - Test Rig Results, Model Calibration and Numerical Prediction
- 2011
-
Ingår i: Wear. - : Elsevier BV. - 0043-1648. ; 271:1-2, s. 92-99
-
Tidskriftsartikel (refereegranskat)abstract
- Conventionally, laboratory measurements under idealized conditions are used to establish parameters needed in different kinds of wear models. This paper presents a procedure for determining the Archard's wear coefficient from data collected in a full-scale wheel-rail test rig, i.e. under realistic loading conditions. Moreover, a simulation procedure capable of simulating rail profile evolution in conformal contacts incorporating both wear and plasticity is presented. In each simulation step, dynamic responses are calculated using the commercial vehicle-track interaction software GENSYS. The conformal contact is treated by applying a multi-Hertzian approach. To account for plastic deformations, a 20 elasto-plastic FE analysis is carried out in conjunction with a 3D local contact analysis in the commercial finite element (FE) software ABAQUS. It is shown that, due to the conformal contact, elastic shakedown is obtained after only a few load cycles and is therefore disregarded in the subsequent analyses. Quantitatively good results, in terms of worn-off area and shape of the worn profile, are presented for simulations between 20k and 100k load cycles. However, dependence between the chosen wear step length and the profiles obtained from the simulations is found.
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| 15. |
- Carlberger, Andreas, 1992, et al.
(författare)
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An iterative methodology for the prediction of dynamic vehicle–track interaction and long-term periodic rail wear
- 2018
-
Ingår i: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. - : SAGE Publications. - 0954-4097 .- 2041-3017. ; 232:6, s. 1718-1730
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a versatile numerical method for the prediction of long-term growth of rail roughness is presented and its functionality is demonstrated for the development of rail corrugation on small radius curves. The procedure includes two sub-modules: (1) a time-domain model for the simulation of dynamic vehicle–track interaction in a wide range of frequencies by using a commercial software for multibody dynamics and (2) a post-calculation of sliding wear based on the Archard’s model in combination with a non-Hertzian and transient wheel–rail contact model. The structural flexibility of the wheelset is accounted for by using the finite element method. The rail wear generated by a large number of passing trains is assessed by recurrently updating the rail surface based on the wear depth calculated in each post- processing step. The current work sets out from a previous study in which a model for the prediction of long-term growth of rail roughness on small radius curves was developed in a general-purpose programming language. By transfer- ring the model into a commercial software, the aim is to develop an engineering tool that is more applicable for different operational conditions, such as various vehicle and track designs and track alignments. The proposed method is verified by comparing the simulation results against those obtained with the pre-existing software. Conditions similar to a 120 m radius curve on the Stockholm metro exposed to corrugation growth on the low rail are considered. The corrugation is found to be generated by the leading wheelsets. The prevailing wavelength-fixing mechanisms are identified and discussed.
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| 16. |
- Eriksson, Olle, 1967-, et al.
(författare)
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Statistical analysis of curve squeal based on long-term onboard noise measurements
- 2022
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Curve squeal with large magnitude tonal components in the frequency range up to 10 kHz is a cause of annoyance without any satisfying solution. This might be partly due to the gaps in the current understanding of the phenomenon within the research community (e.g. the open question whether the fundamental excitation mechanism is due to “falling friction” or “modal coupling”). Rail-bound traffic is expected to become a backbone in the future sustainable public transportation system. This makes it urgent to increase the state of knowledge in order to develop effective mitigation measures against the problem.Noise recorded by an onboard monitoring system during one year of traffic on the Stockholm metro is studied. The influence of selected variables on the generation of curve squeal is investigated in a statistical assessment. The influence of curve radius on curve squeal probability is estimated by calculating the quotient of squealing samples with respect to the total number of samples captured in circular curve sections. Vehicle speed (operative conditions) is modelled by the introduction of a classification representing different speed profiles (e.g. constant, linear acceleration or deacceleration, etc.). Environmental conditions are accounted for by using humidity and air temperature as predictor variables.A general trend of increased probability of curve squeal for decreasing curve radius is observed. Several subsequent regression analyses could not find a consistent influence of air temperature and humidity on the occurrence of curve squeal. Moreover, preliminary results indicate the existence of a vehicle speed for which a curve is particularly prone to generate squeal noise.
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| 17. |
- Eriksson, Olle, 1967-, et al.
(författare)
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Survey of Curve Squeal Occurrence for an Entire Metro System
- 2024
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Ingår i: Noise and Vibration Mitigation for Rail Transportation Systems. - : Springer. - 9789819978519 - 9789819978526 ; , s. 483-490
-
Bokkapitel (refereegranskat)abstract
- The current work presents a statistical analysis based on data collected during approximately 1.5 years of regular operation by two vehicles equipped with an on-board noise monitoring system on the Stockholm metro. Data covers 379,776 passages through 143 curves with radii up to 1000 m. Binary logistic regression is used to investigate the importance of curve radius, vehicle speed, relative humidity, air temperature, rail grinding and vehicle individual on curve squeal. Curve squeal occurrence shows an inverse proportionality with respect to curve radius. This trend is particularly pronounced for curve radii below 600 m. The two vehicles accounted for in the study show differences in propensity to generate squeal. The influence of temperature and relative humidity, and their interaction, on curve squeal is described by an estimated response surface. Results show the occurrence of curve squeal to increase after rail grinding. No strong relationship between curve squeal occurrence and vehicle speed is identified.
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| 18. |
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| 19. |
- Hossein Nia, Saeed, 1983-, et al.
(författare)
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Simulation-based evaluation of maintenance strategies from a life cycle cost perspective
- 2023
-
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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| 20. |
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| 21. |
- Jensen, Niels, et al.
(författare)
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Trafikverkets excellensområde 10 : Systemperspektiv på järnvägen : Enkätundersökning om buller och vibrationer från spårtrafik
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Med målsättning att sammanfatta pågående svensk forskning och utveckling inom spårtrafikbuller och implementering av bullerreducerande åtgärder skickades en enkät ut till cirka 25 experter i oktober 2021. Mottagare av enkäten var kollegor inom infrastrukturförvaltning, Transportstyrelsen, operatörer, konsultfirmor,forskningsinstitut och högskolor. Svarsfrekvensen var cirka 40%.Denna rapport gör inga anspråk på att vara en heltäckande sammanställning om orsaker, konsekvenser, analyser, åtgärder, etc. av buller och vibrationer inducerade av järnvägstrafik. Rapporten reflekterar enbart enkätdeltagarnas svar.Referenserna listade i kapitel 7.6 rekommenderas för grundläggande förståelse av buller och vibrationer
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| 22. |
- Kabo, Elena, 1972, et al.
(författare)
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Rolling contact fatigue prediction for rails and comparisons with test rig results
- 2010
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. - 0954-4097 .- 2041-3017. ; 224:F4, s. 303-317
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Tidskriftsartikel (refereegranskat)abstract
- Tests in a full-scale roller rig, a full-scale linear test rig, and a twin-disc machine are numerically evaluated and compared in terms of rolling contact fatigue loading. From previously evaluated contact patch sizes, a Whler curve relationship is established and matched towards experimentally established fatigue lives. In addition, non-linear finite-element simulations are carried out. Key data needed for the numerical evaluations, as well as difficulties in translating experimental data to numerical models are highlighted. A key parameter here is the interfacial wheel-rail friction. Additional simulations were carried out to establish the latter. However, the conformal contact in the linear test rig makes such simulations very uncertain.
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| 23. |
- Li, Xin, 1985, et al.
(författare)
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Prediction of Vertical Dynamic Vehicle–Track Interaction and Sleeper–Ballast Contact Pressure in a Railway Crossing
- 2020
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Ingår i: Lecture Notes in Mechanical Engineering. - Cham : Springer International Publishing. - 2195-4356 .- 2195-4364. - 9783030380762 ; , s. 397-403
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Konferensbidrag (refereegranskat)abstract
- The vertical dynamic vehicle–track interaction in a railway crossing is simulated in the time domain based on a moving Green’s function approach in combination with an implementation of Kalker’s variational method to solve the non-Hertzian, and potentially multiple, wheel–rail contact. The method is demonstrated by calculating the wheel–rail impact load and the sleeper–ballast contact pressure for a hollow-worn wheel profile passing over a nominal crossing geometry.
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| 24. |
- Li, Xin, 1985, et al.
(författare)
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Simulation of vertical dynamic vehicle-track interaction in a railway crossing using Green's functions
- 2017
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Ingår i: Journal of Sound and Vibration. - : Elsevier BV. - 1095-8568 .- 0022-460X. ; 410, s. 318-329
-
Tidskriftsartikel (refereegranskat)abstract
- Vertical dynamic vehicle-track interaction in the through route of a railway crossing is simulated in the time domain based on a Green's function approach for the track in combination with an implementation of Kalker's variational method to solve the non-Hertzian, and potentially multiple, wheel-rail contact. The track is described by a linear, three-dimensional and non-periodic finite element model of a railway turnout accounting for the variations in rail cross-sections and sleeper lengths, and including baseplates and resilient elements. To reduce calculation time due to the complexity of the track model, involving a large number of elements and degrees-of-freedom, a complex-valued modal superposition with a truncated mode set is applied before the impulse response functions are calculated at various positions along the crossing panel. The variation in three-dimensional contact geometry of the crossing and wheel is described by linear surface elements. In each time step of the contact detection algorithm, the lateral position of the wheelset centre is prescribed but the contact positions on wheel and rail are not, allowing for an accurate prediction of the wheel transition between wing rail and crossing rail. The method is demonstrated by calculating the wheel-rail impact load and contact stress distribution for a nominal S1002 wheel profile passing over a nominal crossing geometry. A parameter study is performed to determine the influence of vehicle speed, rail pad stiffness, lateral wheelset position and wheel profile on the impact load generated at the crossing. It is shown that the magnitude of the impact load is more influenced the wheel-rail contact geometry than by the selection of rail pad stiffness.
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| 25. |
- Li, Xin, 1985, et al.
(författare)
-
Simulation of wheel–rail impact load and sleeper–ballast contact pressure in railway crossings using a Green's function approach
- 2019
-
Ingår i: Journal of Sound and Vibration. - : Elsevier BV. - 1095-8568 .- 0022-460X. ; 463
-
Tidskriftsartikel (refereegranskat)abstract
- A method for the simulation of dynamic vehicle–track interaction and evaluation of measures to improve the design of railway crossings is presented. To accurately represent the high-frequency dynamics and non-linear contact conditions of the vehicle–track system, the vertical interaction between a wheelset and the crossing is simulated in the time domain using a Green's function approach based on extensive finite element models of track and wheelset in combination with an implementation of Kalker's variational method to solve the non-Hertzian, and potentially multiple, wheel–rail contact. Both wheels of the wheelset in simultaneous contact with the crossing rail and the outer rail are considered. Rigid and flexible wheelset models are compared. The sampled contact geometry of the crossing, including the discrete irregularity between the wing rail and the crossing nose, is used to determine a three-dimensional surface geometry between each pair of adjacent rail cross-sections. A parameter study is performed to investigate the influence of crossing design on the maximum vertical wheel–rail contact force and the contact pressure generated at the sleeper–ballast interface. It is concluded that a design with a combination of increased sleeper width, softer rail pads and implementation of under sleeper pads (USP) will reduce the track stiffness gradients in the crossing panel and mitigate the risk of differential track settlement by lowering the sleeper–ballast contact pressure.
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| 26. |
- Li, Xin, 1985, et al.
(författare)
-
Vertical dynamic vehicle-track interaction in a railway crossing predicted by moving Green's functions
- 2016
-
Ingår i: 24th Symposium of the International Association for Vehicle System Dynamics, IAVSD 2015; Graz; Austria; 17 August 2015 through 21 August 2015. - : CRC Press. ; , s. 1319-1327
-
Konferensbidrag (refereegranskat)abstract
- A versatile and computationally efficient method for simulation of high-frequency dynamic vehicle–track interaction in a railway crossing is presented. The track model is based on a linear, time-invariant and non-periodic finite element model of a railway turnout accounting for variations in rail cross-sections and sleeper lengths, and including baseplates and resilient elements. To account for the longitudinal motion of the wheel, a set of moving Green’s functions is pre-calculated to represent the dynamics of the crossing. The lateral position of the wheel centre (but not the contact positions on wheel and rail) is prescribed and could be determined by a previous simulation of dynamic vehicle–track interaction using a multibody dynamics software. The vehicle model includes one half of a wheelset and the primary suspension. In each time-step of the simulation, the three-dimensional surface geometry of crossing and wheel is described by fournoded linear elements. Vertical non-Hertzian (potentially multiple) wheel–rail contact is solved by an implementation of Kalker’s variational method CONTACT. The method is demonstrated by calculating the impact load and wheel–rail contact stress distribution for the case with a nominal S1002 wheel profile passing over a nominal crossing geometry.
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| 27. |
- Mirzanamadi, Raheb, 1987-, et al.
(författare)
-
Lateral Track Buckling in Sweden : Insights from Operators and Infrastructure Managers
- 2024
-
Ingår i: CivilEng. - : MDPI. - 2673-4109. ; 5:1, s. 136-149
-
Tidskriftsartikel (refereegranskat)abstract
- Rail transport is expected to become a key component in the development of a long-term sustainable transport system. The planning, construction, operation, and maintenance of railway infrastructure are crucial in this effort. Hence, it is essential to ascertain that the railway infrastructure withstands and is adapted to extreme weather conditions and climate change. This study focuses on evaluating climate adaptation measures for lateral track buckling in Sweden. Through a literature review and interview with an expert at Swedish Transport Administration, it is highlighted that the maintenance status of railway infrastructure plays a significant role in the occurrence of lateral track buckling. According to the expert, inadequate track maintenance is the primary cause of lateral track buckling rather than weather variables like air temperature. The interview also clarifies that the chain of events related to the handling of track buckling is mainly initiated by the observation of a discrete lateral irregularity by a train driver, whereupon the train dispatcher at the traffic management center stops traffic until the location in the track has been inspected by a track entrepreneur. During the inspection, up to half of the observed cases of track buckling turn out to be false.
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| 28. |
- Nielsen, Jens, 1963, et al.
(författare)
-
Wheel–Rail Impact Loads, Noise and Vibration: A Review of Excitation Mechanisms, Prediction Methods and Mitigation Measures
- 2021
-
Ingår i: Notes on Numerical Fluid Mechanics and Multidisciplinary Design. - Cham : Springer International Publishing. - 1612-2909 .- 1860-0824. ; , s. 3-40, s. 3-40
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Railway noise and ground-borne vibration induced by wheel–rail impact loads are generated by discrete wheel/rail surface irregularities or local deviations in the nominal wheel–rail contact geometry. On the running surface of a rail, a discrete irregularity can be inherent to the railway design, for example at crossings or insulated joints. On the wheel or rail, the irregularity could also be the result of surface damage due to rolling contact fatigue cracking or a consequence of wheel sliding without rolling. This review describes the mechanisms of wheel–rail impact generated by wheel flats, rail joints and crossings. These can be a source of locally increased noise and vibration levels and increased annoyance, as well as of damage to vehicle and track components. The wheel–rail excitation at such irregularities, as indicated by the vertical wheel centre trajectory, leads to an abrupt change of momentum, potentially causing a momentary loss of wheel–rail contact followed by an impact on the rail. The resulting loading is a transient and often periodically repeated event exciting vibration in a wide frequency range with most of the energy concentrated below about 1 kHz. For the numerical prediction of high-magnitude transient loading and situations potentially leading to loss of contact, a non-linear wheel–rail contact model is required, implying that the simulation of contact force is carried out in the time domain. To avoid the need for large, computationally expensive models, a hybrid approach has been developed in which the time history of the contact force is transformed into an equivalent roughness spectrum; this is used as input to frequency-domain models for the prediction of noise and vibration. Since the excitation mechanism is similar to that for rolling noise, the same types of measures to mitigate wheel and track vibration can be applied. However, the main priority should be to control the irregularity by design and regular maintenance.
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| 29. |
- Nilsson, Rickard, et al.
(författare)
-
Utredning och provning av kostnadseffektiva metoder för bullerminimering av spårfordon
- 2013
-
Ingår i: Transportforum 2013. - Linköping : Statens väg- och transportforskningsinstitut. ; , s. 122-135
-
Konferensbidrag (refereegranskat)abstract
- Den här artikeln avser att för ett befintligt spårtrafiksystem översiktligt beskriva olika bullerreducerande åtgärders effekt, deras ekonomiska aspekter samt indirekt inverkan på systemet och dess omgivning. SL (AB Storstockholms Lokaltrafik) arbetar aktivt för att minska tågtrafikens störning till omgivningen, med den långsiktiga strävan att hela SLs spårsystem ska innehålla riktvärden för ny- och ombyggd järnväg enligt infrastrukturpropositionen. Ett viktigt medel för att nå denna ambition är succesivt byte av fordonsparken till nya och tystare fordon, detta kommer dock inte ge tillräcklig bullerreduktion, ytterligare åtgärder kommer att krävas. Beroende på problembilden kan det innebära att en enstaka åtgärd eller flera åtgärder i kombination behöver tas till. För att kartlägga, utvärdera och skapa kunskap om olika åtgärdsalternativ har SL därför arbetat långsiktigt och systematiskt med att utvärdera ett antal olika metoder. En viktig aspekt i sammanhanget är att då SLs spår till stor del går mycket nära bostäder är det önskvärt att hitta effektiva bullerskyddsåtgärder med så liten påverkan som möjligt avseende landskapsbild och barriäreffekt. Med hänsyn till ägardirektivet om ekonomi i balans är det även viktigt att se till total nytta relativt total kostnad vid val av åtgärd.
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| 30. |
- Nyberg, Erik, 1992-, et al.
(författare)
-
Impact of DAC on production personnel at marshalling yards : Deliverable D 5.1
- 2023
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The current deliverable is an outcome of the EU-project titled DACcelerate part of WP4 (Infrastructure, capacity and modal shift/Green deal) in the European DAC Delivery Programme (EDDP, under the WP structure valid until end-2022). EDDP WP4 has been led by Trafikverket who is also in various leading positions/WPs in TRANS4M-R and EDDP neo. The overall objective DACcelerate WP5 is to investigate the changes in work environment at marshalling yards that a transition from screw couplers to Digital Automatic Couplers (DAC)entails. Production at the main marshalling yards of Sweden and Austria is analysed and compared. These two marshalling yards represent significant differences in terms of traffic throughput, physical design and organisation of production personnel. Job tasks performed by different professional roles at the marshalling yard has been surveyed as well as how personnel interact in accordance with current work processes. The research method applied in the current work has primarily involved workplace visits and interviews and hence the investigation has required a close collaboration with operators of marshalling yards. For the case studies in Sweden and Austria this has meant a comprehensive and trustful cooperation with the operator Green Cargo and the Austrian federal railways ÖBB. The current project has been integrated in WP4 of the EDDP programme as well as aligned with unions and other stakeholders through workshop sheld during the period when the project was carried out.
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| 31. |
- Nyberg, Erik, 1992-, et al.
(författare)
-
Sammanställning av tillgänglig information om kurvskrik på Trafikverkets järnvägsanläggning
- 2023
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Det aktuella arbetet utgör den första leveransen från ett forskningsprojekt med fokus på problematiken relaterad till utstrålning av kurvskrik. Projektet som helhet koncentrerar sig på kurvskriksgenereringens grundorsaker med tungvikt vid betydelsen av infrastrukturens utformning och underhållsstatus. Ytterligare leveranser från det aktuella projektet kommer inkludera flera artiklar i akademiska journaler. I detta PM beskrivs utgångsläget inför ett framtida arbete med att minska störning orsakad av kurvskrik från Trafikverkets järnvägsanläggning. Relevanta data för att undersöka exponering för kurvskrik i form av information om anläggningens fysiska utformning och egenskaper (t.ex. kurvradie, rälprofil, etc.), trafikering (t.ex. trafikmängd och typ av fordon) och befolkningstäthet inhämtas och används i en samlad analys. Kurvor med förutsättningar att orsaka störning på grund av skrikljud lokaliseras (dvs. snäva kurvor lokaliserade i tätbebyggt område med betydande trafikering). Genom att det möjliggör en bedömning av problemets omfattning visar PM:et på resultat som bör utgöra en naturlig komponent i ett framtida strategiskt åtgärdsarbete med avseende på kurvskrik. Resultaten visar att Trafikverkets järnvägsanläggning rymmer 720 kilometer spår med cirkulärkurvor med radie under 500 meter. Av dessa finns ca 90 kilometer på platser där det bor fler än 200 personer inom ett avstånd av 300 meter från spåret. Kombinationen av snäv kurvradie och hög befolknings[1]täthet gör dessa platser intressanta att studera med avseende på exponering av kurvskrik. Generellt indikerar resultaten att trafikeringen på kurvsegmenten med upp till 1 000 meter radie domineras av persontåg. För fall med kurvsegment som tillhör platser eller bandelar med årsdygnstrafik på över 250 tåg (endast observerat för persontåg) är över 50 % av den associerade spårlängden belägen så att fler än 200 personer har sin bostad inom ett avstånd om 300 meter från spåret.
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| 32. |
- Odolinski, Kristofer, 1984-, et al.
(författare)
-
Vehicle, Energy, and noise modules of UCM 2.0 : Deliverable D1.2
- 2022
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This deliverable covers the scientific analysis and implementation proposal for the Vehicle, Energy, and Noise modules of UCM 2.0. UCM2.0 is the new version of the Universal Cost Model (UCM) which was made available after the H2020 Roll2Rail project. Overall, it contains a description of the upgraded UCM2.0 capabilities regarding Energy and Noise calculations and cost valuations (Task 1.3) and Vehicle damage and maintenance modelling (Task 1.4). These tasks were part of WP1-Universal Cost Model 2.0 and will have a continuation with the deliverable D1.3, entitled “UCM 2.0 tool and user guide with default parameters and recommendations”. This D1.2 deliverable together with D1.1 Infrastructure module of UCM 2.0 constitutes a full picture of the scientific background, technical developments and structure proposals for this new version of the Universal Cost Model. The document provides an extensive study of CO2 emissions and cost as this was an important add-in for the UCM2.0. This part analyses CO2 emissions from rail transport, methods to monetise the cost of CO2 emissions, how the approach is implemented in different countries and finally how these CO2 costs are included in the Energy Module of UCM2.0. This Energy module of the UCM2.0 is based on the model of the previous UCM version, but some changes are proposed specifically some considerations regarding the relative importance of the different energy consumption terms and the energy consumption of auxiliary components. Some extensive information is provided regarding regenerative braking and energy storage systems which is valuable for the energy refeed calculations needed as inputs.
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| 33. |
- Pieringer, Astrid, 1979, et al.
(författare)
-
Curve squeal of rail vehicles: Linear stability analysis and non-linear time-domain simulation
- 2016
-
Ingår i: Civil-Comp Proceedings. - 1759-3433. ; 110
-
Tidskriftsartikel (refereegranskat)abstract
- Railway curve squeal arises from self-excited vibrations during curving. In this paper, a combination of a frequency-and a time-domain approach for curve squeal is applied in order to compare and evaluate the two different approaches. In the frequency-domain, linear stability is investigated through complex eigenvalue analysis. The time-domain model is based on a Green's functions approach and uses a convolution procedure to obtain the system response. To ensure comparability, the same submodels are implemented in both squeal models. The wheel model includes a single flexible wheel and accounts for inertia effects due to rotation adopting Eulerian coordinates. The track is modelled using the moving element method technique corresponding to a finite element mesh that travels with the vehicle speed. Coulomb's law with a constant friction coefficient is applied to model the local friction characteristics in the contact zone. The frictional instability arises due to geometrical coupling. The rolling contact model applied is Kalker's variational method in the time domain and a linearized version of this method in the frequency domain. Conditions similar to those of a curve on the Stockholm metro exposed to severe curve squeal are studied with both squeal models. The influence of the wheel-rail friction coefficient and the direction of the resulting creep force on the occurrence of squeal is investigated for vanishing train speed. The results of both models show similar tendencies, but differ in the predicted squeal frequencies.
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| 34. |
- Pieringer, Astrid, 1979, et al.
(författare)
-
Investigation of railway curve squeal using a combination of frequency- and time-domain models
- 2016
-
Ingår i: Proceedings of the 12h International Workshop on Railway Noise (IWRN12), Terrigal, Australia, September 12-16. ; , s. 444 - 451
-
Konferensbidrag (refereegranskat)abstract
- Railway curve squeal arises from self-excited vibrations during curving. In this paper, a frequency- and a timedomainapproach for curve squeal are compared. In particular, the capability of the frequency-domain model topredict the onset of squeal and the squeal frequencies is studied. In the frequency-domain model, linear stabilityis investigated through complex eigenvalue analysis. The time-domain model is based on a Green's functionsapproach and uses a convolution procedure to obtain the system response. To ensure comparability, the samesubmodels are implemented in both squeal models. The structural flexibility of a rotating wheel is modelled byadopting Eulerian coordinates. To account for the moving wheel‒rail contact load, the so-called moving elementmethod is used to model the track. The local friction characteristics in the contact zone is modelled inaccordance with Coulomb's law with a constant friction coefficient. The frictional instability arises due togeometrical coupling. In the time-domain model, Kalker's non-linear, non-steady state rolling contact modelincluding the algorithms NORM and TANG for normal and tangential contact, respectively, is solved in eachtime step. In the frequency-domain model, the normal wheel/rail contact is modelled by a linearization of theforce-displacement relation obtained with NORM around the quasi-static state and full-slip conditions areconsidered in tangential direction. Conditions similar to those of a curve on the Stockholm metro exposed tosevere curve squeal are studied with both squeal models. The influence of the wheel-rail friction coefficient andthe direction of the resulting creep force on the occurrence of squeal is investigated for vanishing train speed. Results from both models are similar in terms of the instability range in the parameter space and the predictedsqueal frequencies.
|
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| 35. |
- Pieringer, Astrid, 1979, et al.
(författare)
-
Investigation of railway curve squeal using a combination of frequency- and time-domain models
- 2018
-
Ingår i: Notes on Numerical Fluid Mechanics and Multidisciplinary Design. - Cham : Springer International Publishing. - 1612-2909 .- 1860-0824. ; , s. 83-95
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Railway curve squeal arises from self-excited vibrations during curving. In this paper, a frequency- and a time-domain approach for curve squeal are compared. In particular, the capability of the frequency-domain model to predict the onset of squeal and the squeal frequencies is studied. In the frequency-domain model, linear stability is investigated through complex eigenvalue analysis. The time-domain model is based on a Green’s function approach and uses a convolution procedure to obtain the system response. To ensure comparability, the same submodels are implemented in both squeal models. The structural flexibility of a rotating wheel is modelled by adopting Eulerian coordinates. To account for the moving wheel–rail contact load, the so-called moving element method is used to model the track. The local friction characteristics in the contact zone are modelled in accordance with Coulomb’s law with a constant friction coefficient. The frictional instability arises due to geometrical coupling. In the time-domain model, Kalker’s non-linear, non-steady state rolling contact model including the algorithms NORM and TANG for normal and tangential contact, respectively, is solved in each time step. In the frequency-domain model, the normal wheel/rail contact is modelled by a linearization of the force-displacement relation obtained with NORM around the quasi-static state and full-slip conditions are considered in the tangential direction. Conditions similar to those of a curve on the Stockholm metro exposed to severe curve squeal are studied with both squeal models. The influence of the wheel-rail friction coefficient and the direction of the resulting creep force on the occurrence of squeal is investigated for vanishing train speed. Results from both models are similar in terms of the instability range in the parameter space and the predicted squeal frequencies.
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| 36. |
|
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| 37. |
- Pieringer, Astrid, et al.
(författare)
-
Transient Modelling of Curve Squeal Considering Varying Contact Conditions
- 2024
-
Ingår i: Noise and Vibration Mitigation for Rail Transportation Systems. - : Springer. - 9789819978519 - 9789819978526 ; , s. 491-499
-
Bokkapitel (refereegranskat)abstract
- Modelling railway curve squeal poses a challenge since the phenomenon is non-linear, transient and complex. This work focusses on the transient effects of varying contact parameters on curve squeal. A previously developed high-frequency tool for the simulation of curve squeal in the time domain during quasi-static curving is extended to account for transient curving and connected to a software for the low-frequency vehicle dynamics. An application of the model demonstrates that time-varying contact parameters such as contact position, lateral creepage, and friction coefficient can lead to an on- and offset of squeal. The history of the wheel/rail dynamics can also have an influence on the occurrence of squeal and the selection of the squeal frequency.
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| 38. |
- Pieringer, Astrid, et al.
(författare)
-
Verification of a Transient Model for the Simulation of Curve Squeal on the Basis of On-Board Noise Monitoring Data from Stockholm Metro
- 2023
-
Ingår i: Proceedings of Fortschritte der Akustik. - : Deutsche Gesellschaft für Akustik (DEGA). ; , s. 693-696
-
Konferensbidrag (refereegranskat)abstract
- Curve squeal is an intense tonal noise emitted by railway vehicles negotiating tight curves. It is attributed to self-excited vibrations of the railway wheel during ’imperfect’ curving. Modelling curve squeal poses a challenge since the phenomenon is non-linear and transient. In this work, a previously developed model for the simulation of curve squeal during transient curving is verified based on on-board noise monitoring data from Stockholm metro.The time-domain squeal model combines pre-calculated impulse response functions for track and wheel dynamics with Kalker’s variational method for transient rolling contact. The model includes the coupling between vertical and tangential dynamics and considers varying contact positions on wheel and rail along the curve. The low-frequency curving behaviour is included by a pre-calculation with a software for simulation of three-dimensional dynamic vehicle-track interaction.In previous work, a statistical analysis was carried out based on data collected with an on-board noise monitoring system during approximately 1.5 years of regular operation by two vehicles on Stockholm metro. Results showed, amongst others, that curve squeal occurrence increases with decreasing curve radius, and after rail grinding. Simulations are carried out with the curve squeal model to replicate and analyze observations from the noise monitoring on Stockholm metro.
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| 39. |
- Sitte de Longueval, Oriane, et al.
(författare)
-
Deliverable D 8.4 : Final Skills and qualifications and creating agile organizations (final report)
- 2021
-
Rapport (refereegranskat)abstract
- This study concerns a crisis management team (CMT) that has been set up in France at SNCF to make the company more agile in the face railway incidents that cause passenger flow management problems. From the crisis management literature, the sociology of professions and an in depth ethnography, this study investigates the professionalization and de-professionalization of the CMT through its story of success and failure.Core findings reveal three key episodes from the creation of the CMT to its decline. For each of these phases, the data show how organizational and professional logics can support or hinder each other. The balance between normal and agile organization always appears delicate to find and maintain. Results question the relevance of integrating crisis management as a profession in railway organizations and highlight the difficulty to maintain agility within “bureaucratic” organization. It finally provides some practical outcomes by comparing the agility of two models (professional group model vs. expert network model) in managing crises.Then, a quantitative investigation of the future development of skills and qualifications is presented. Due to the many variables that need to be taken into account in such an assessment (e.g. long-term investment planning), the study has been limited to the Swedish railway industry and the part of the sector related to infrastructure for which detailed employment data was available. This part of the investigation focuses on the influence on human capital from innovations in Shift2rail Innovation Programme 3 (IP3).Results indicate that IP3 will have an overall impact at system level (e.g. increased productivity enabled by improved long-term maintenance planning and operation) rather than affecting specific professional roles. In contrast, the impact of the technological development of Shift2rail IP2 and IP5 is anticipated to affect specific operational jobs (e.g. train drivers, train attendees, train operations managers, etc.) both with respect to employment levels and skills requirements.
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| 40. |
- Svanberg, Lisa, 1986-, et al.
(författare)
-
Kartläggning av personal med järnvägsspecifik kompetens knuten till svensk infrastruktur för spårburen trafik : delrapport 2 av 3 i projektet ”Prognosmodell för framtida kompetens- och resursbehov knutet till svensk infrastruktur för spårburen trafik”
- 2020
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Den planerade kostnaden för drift och underhåll av Trafikverks järnvägsanläggning mellan åren 2018–2029 är 47 % högre jämfört med den från föregående planperiod. Därtill föreslås investeringar i ny statlig järnvägsinfrastruktur. Även lokaltrafiken expanderar med förlängning av befintlig, och byggnation av ny, spårväg- och/eller tunnelbana i Göteborg och Stockholm som exempel. För att säkerställa genomförandet av dessa insatser krävs att branschen kan möta den efterfråga på kompetens och resurser som väntar. Spårentreprenadföretagen har via branschorganisationen Sveriges Byggindustrier varnat för att detta kan bli bekymmersamt. Detta grundar sig på en prognos att det kommer råda brist på ca 1 700 personer inom yrkeskategorierna ban-, el-, signal- och teletekniker inom några år.Denna rapport utgör den andra av totalt tre leveranser från ett forskningsprojekt med syfte att utveckla en praktiskt användbar modell för att prognostisera framtida kompetens- och resursbehov knutet till svensk infrastruktur för spårburen trafik. Projektet leds av Statens väg- och transportforskningsinstitut (VTI) med finansiering från, och i samarbete med, Trafikverket. I den aktuella deletappen har kompetenssammansättningen och åldersstrukturen hos personal knuten till infrastruktur för spårburen trafik kartlagts. Denna information utgör ett viktigt underlag för den efterföljande prognosen över framtida kompetens- och resursbehov. Kartläggningen har inkluderat både privata aktörer (spårentreprenör- och teknikkonsultbolag) och offentlig förvaltning (förvaltare av infrastruktur för både regional- och lokaltrafik och spårentreprenörbolag). Resultaten från studien redovisas i sammanslagen form för samtliga organisationer inom respektive branschsegment (spårentreprenörer, teknikkonsultbolag och infrastrukturförvaltare). I tillägg har tillgången på järnvägsspecifika utbildningsprogram/-kurser på gymnasie-, yrkeshögskole- och högskolenivå kartlagts.
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| 41. |
- Torstensson, Peter, 1981, et al.
(författare)
-
High-Frequency Vertical Wheel-Rail Contact Forces at High Vehicle Speeds-The Influence of Wheel Rotation
- 2012
-
Ingår i: Notes on Numerical Fluid Mechanics and Multidisciplinary Design. - Tokyo : Springer Japan. - 1612-2909 .- 1860-0824. - 9784431539261 ; 118, s. 43-50
-
Konferensbidrag (refereegranskat)abstract
- Dynamic vehicle-track interaction at high vehicle speeds is investigated in a frequency range from about 20 Hz to 3 kHz. The inclusion of wheel rotation in the vehicle model is investigated by implementing a structural dynamics model of a rotating wheelset in an existing simulation environment. Calculated wheel-rail contact forces using this comprehensive flexible wheelset model are compared with contact forces based on less detailed, non-rotating wheelset models. Load cases including broad-band wheel-rail excitation due to vertical rail irregularities (rail corrugation) and impact excitation caused by a local deviation from the nominal wheel radius (wheel flat) are considered. Viewed from the excitation point, each wheelset resonance peak of multiplicity two splits into two peaks; the separation of the two peaks increases with increasing rotational speed. If the wheelset model is excited at a frequency where two different mode shapes, due to the wheel rotation, have coinciding resonance frequencies, the contact force calculated for the rotating wheelset model differs significantly from those of the non-rotating models. Further, the use of a flexible rotating wheelset model is recommended for load cases leading to large magnitude contact force components in the high-frequency range (above 1.5 kHz). In particular, the influence of the radial wheel eigenmodes with two or three nodal diameters is significant.
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| 42. |
|
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| 43. |
- Torstensson, Peter, 1981, et al.
(författare)
-
Hybrid model for prediction of impact noise generated at railway crossings
- 2016
-
Ingår i: Proceedings of the 12h International Workshop on Railway Noise (IWRN12), Terrigal, Australia, September 12-16 (2016). ; , s. 539 - 545
-
Konferensbidrag (refereegranskat)abstract
- A hybrid model for the prediction of impact noise at railway crossings is presented. The hybrid model combines the simulation of vertical wheel‒rail contact force in the time domain and the prediction of sound pressure level using a linear frequency-domain model. The time-domain model uses moving Green’s functions for the vehicle and track models (accounting for wheel flexibility and a discretely supported rail with space-variant beam properties) and a non-Hertzian wheel‒rail contact model. The time-domain and frequency-domain models are coupled based on the concept of an equivalent roughness spectrum. The model is demonstrated by investigating the influence of axle load, vehicle speed and wheel profile on generated impact noise levels. A negligible influence on impact noise is observed for axle loads in the interval 15 – 25 tonnes. On the other hand, increasing vehicle speed from 80 km/h to 150 km/h, or comparing a nominal S1002 wheel profile with a severely hollow worn profile, result in substantially higher levels of impact noise; for the given wheel and track conditions the differences are in the order of 10 dB(A).
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| 44. |
- Torstensson, Peter, 1981, et al.
(författare)
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Hybrid model for prediction of impact noise generated at railway crossings
- 2018
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Ingår i: Notes on Numerical Fluid Mechanics and Multidisciplinary Design. - Cham : Springer International Publishing. - 1612-2909 .- 1860-0824. ; , s. 759-769, s. 759-769
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- A hybrid model for the prediction of impact noise at railway crossings is presented. The hybrid model combines the simulation of vertical wheel‒rail contact force in the time domain and the prediction of sound pressure level using a linear frequency-domain model. The time-domain model uses moving Green’s functions for the vehicle and track models (accounting for wheel flexibility and a discretely supported rail with space-variant beam properties) and a non-Hertzian wheel‒rail contact model. The time-domain and frequency-domain models are coupled based on the concept of an equivalent roughness spectrum. The model is demonstrated by investigating the influence of axle load, vehicle speed and wheel profile on generated impact noise levels. A negligible influence on impact noise is observed for axle loads in the interval 15–25 tonnes. On the other hand, increasing vehicle speed from 80 to 150 km/h, or comparing a nominal S1002 wheel profile with a severely hollow worn profile, result in substantially higher levels of impact noise; for the given wheel and track conditions the differences are in the order of 10 dB(A).
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| 45. |
- Torstensson, Peter, 1981-, et al.
(författare)
-
LCC evaluation of rail maintenance strategies using simulations of long-term mechanical degradation
- 2024
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Ingår i: Sammanställning av referat från Transportforum 2024. - Linköping : Statens väg- och transportforskningsinstitut. ; , s. 408-409
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Rail infrastructure is an important part of transport systems, improving accessibility and contributing to economic growth. This requires costly maintenance and renewal activities that are subject to budget constraints. There is a need to carry out the right activity at the right time to make best use of limited resources. This paper proposes a methodology to evaluate the performance of different rail grinding strategies from a life cycle cost (LCC) perspective. The procedure is innovative in such a way that it uses simulations of long-term mechanical degradation with respect to different maintenance interventions and combines these simulations with an assessment of the associated economic impact. The utilisation of mechanical modelling makes the procedure able to analyse new/innovative maintenance strategies or changes in infrastructure/vehicle design, as well as to perform optimisation and parameter studies under controlled conditions. The proposed methodology for LCC evaluation is applied to compare the performance of different maintenance strategies on a 495 m radius curve on the Iron-ore line in Sweden. The traffic consists of freight trains containing two back-to-back connected three-axle locomotives and 67 wagons on three-piece bogies. The annual traffic volume is around 37 mega gross tonnes (MGT) corresponding to around 20 train passages each day, half (un)loaded, with 30 tonnes axle load. Three different maintenance strategies are investigated; (S1) the currently applied strategy on the Iron-ore line corresponding to rail grinding performed biannually on rail material R350LHT, (S2) rail grinding performed annually on rail material R400HT, and (S3) the same as (S1) but with gauge width correction performed to prevent it from exceeding 1450 mm. Long-term rail profile evaluation due to mechanical degradation and rail grinding is assessed by iterative simulations of dynamic vehicle–track interaction in the software GENSYS. Rail damage due to wear and rolling contact fatigue are modelled in accordance with Archard’s theory and the method by KTH, respectively.
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| 46. |
- Torstensson, Peter, 1981, et al.
(författare)
-
Monitoring of rail corrugation growth due to irregular wear on a railway metro curve
- 2009
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Ingår i: Wear. - : Elsevier BV. - 0043-1648. ; 267, s. 556-561
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Tidskriftsartikel (refereegranskat)abstract
- Short-pitch rail corrugation developing on the low rail in sharp curves is a problem experienced by many railway networks worldwide. Because of the large existence of small radius curves, metro lines are particularly affected. This case study is performed as part of a project which aims at developing a numerical tool for prediction of rail corrugation growth on curves. The development of corrugation on a 120 m radius curve of the Stockholm metro has been monitored by repeated measurements of rail roughness and train pass-by noise. Within a grinding interval of 1 year, severe short-pitch corrugation was build up with maximum peak-to-peak magnitudes of about 0.15 mm. Spectral analysis of measurement data shows large roughness magnitudes in the wavelength interval 4–14 cm, with peaks at approximately 5 cm and 8 cm. The corrugation pattern has a pure longitudinal direction (with corrugation ridges transverse to the track direction) and an irregularly varying magnitude along the 100 m long measured track section. The roughness growth rate increased with time until 300 days after rail grinding, thereafter only moderate additional roughness growth was observed. Because of moderate train speeds of about 30 km/h, the rolling noise caused by the corrugation has a low-frequency content (
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| 47. |
- Torstensson, Peter, 1981-, et al.
(författare)
-
Prognos över framtida kompetens- och resursbehov knutet till svensk infrastruktur för spårburen trafik : delrapport 3 av 3 i projektet ”Prognosmodell för framtida kompetens- och resursbehov knutet till svensk infrastruktur för spårburen trafik”
- 2020
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Prognosens utgångspunkt är infrastrukturförvaltarnas långsiktiga budget bestående av tusentals budgetsatta åtgärder med planerat år för utförande. Denna har samlats in från Trafikverket, Region Stockholm och Trafikkontoret i Göteborg. Med hjälp av så kallade åtgärdsmodeller föreskrivs hur åtgärdens kostnad fördelar sig över branschsegmenten; infrastrukturförvaltare, teknikkonsultbolag och spårentreprenörer. I (Svanberg et al. 2020) presenteras en kartläggning av branschens kompetens- och ålderssammansättning inom yrkesroller med järnvägsspecifik kompetens. Insamlingen av data inkluderar 16 branschaktörer och 58 yrkesroller. Personalantalet med järnvägsspecifik kompetens uppskattas till 5 865 personer fördelade över branschsegmenten på följande sätt; 3 654 st hos spårentreprenörer, 1 377 st hos teknikkonsultbolag och 834 st hos infrastrukturförvaltare.Prognoser över framtida behov och brist på personal med järnvägsspecifik kompetens har tagits fram för tidsperioden 2019–2025. Det prognostiserade totala behovet av personal med denna kompetens vid år 2025 är 7 032 personer vilket är en ökning med 20 % jämfört med dagens antal. Det är främst teknikkonsultbolagens och infrastrukturförvaltarnas personal som beräknas påverkas av detta ökade behov. Den största personalbristen under den studerade perioden predikteras att drabba spårentreprenörerna vid år 2021 och då uppgå till 870 personer.
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| 48. |
- Torstensson, Peter, 1981-, et al.
(författare)
-
Prognosmetod för framtida kompetens- och resursbehov knutet till svensk infrastruktur för spårburen trafik : delrapport 1 av 3 i projektet Prognosmodell för framtida kompetens- och resursbehov knutet till svensk infrastruktur för spårburen trafik
- 2019
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Utvecklingen inom järnvägen drivs av en ökande efterfrågan på hållbara och punktliga transporter från både näringsliv och en växande befolkning. Jämfört med 2014 prognostiserar Trafikverket en ökning av persontransportarbetet på järnväg med 54 % fram till 2040. Trafikverket beskriver i Nationell plan för transportsystemet 2018–2029 den största satsningen på järnvägen i modern tid. Detta inkluderar t.ex. deletapper av höghastighetsjärnvägsnätet med en planerad total slutlig längd på 1 500 km. Därutöver tillkommer insatser som övriga infrastrukturförvaltare i Sverige planerar att genomföra. Branschen har belyst behovet av kunskapsuppbyggnad och kompetensförstärkning för att kunna möta dessa framtida behov. Inom järnvägsteknikeryrken är kompetensbristen redan betydande och en aktuell svårighet för spårentreprenadföretagen att hantera. En utredning från Sveriges Byggindustrier bedömer att det inom några år kommer råda brist på 1 700 nyckelpersoner inom dessa yrkesgrupper.Denna rapport redovisar resultatet från den första arbetsetappen i ett större forskningsarbete med syfte att utveckla en praktiskt användbar modell för att prognostisera framtida kompetens- och resursbehov knutet till svensk infrastruktur för spårburen trafik. Projektet leds av Statens väg- och transportforskningsinstitut (VTI) med finansiering från, och i samarbete med, Trafikverket. Som ägare av stora infrastrukturanläggningar för spårburen trafik deltar Region Stockholm (SL), Trafikkontoret i Göteborg (Göteborgs spårvägar) samt Norrköpings spårvägar i projektets referensgrupp. Resultatet från projektet förväntas bli värdefullt ur flera aspekter. Bland annat som beslutsunderlag för kompetensförsörjningsinsatser så som utökning av antalet utbildningsplatser och utformningen av innehållet hos desamma, samt åtgärder för att öka branschens attraktionskraft. Vidare möjliggör prognosmetoden för branschaktörer att göra långsiktig strategisk planering som motsvarar och anpassas efter tillgången på resurser och kompetens.
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| 49. |
- Torstensson, Peter, 1981, et al.
(författare)
-
Rail Acceleration Induced by Train Pass-by—Field Measurements and Validation of a Simulation Model
- 2022
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Ingår i: Lecture Notes in Mechanical Engineering. - Cham : Springer International Publishing. - 2195-4356 .- 2195-4364. ; , s. 302-311, s. 302-311
-
Konferensbidrag (refereegranskat)abstract
- The applicable frequency range of an existing code for simulation of vertical dynamic vehicle–track interaction is extended by implementation of a more advanced track model that includes the rail modelled by solid three-dimensional finite elements. In this paper, a previous validation of the software with respect to magnitudes of dynamic wheel–rail contact forces is supplemented by a comparison of measured and simulated rail accelerations at train pass-by. To this end, data collected as part of an extensive field measurement campaign related to the adaptation of the software CNOSSOS-EU to conditions on the Swedish railway infrastructure is used. In particular, the dataset includes measurements of track receptance, rail roughness, wheel out-of-roundness and pass-by rail acceleration. The results calculated when using a simplified two-dof mass-spring-damper wheelset model and a track model accounting for the rail by Rayleigh–Timoshenko beam elements show good agreement with those obtained for more advanced wheelset and track models deploying three-dimensional solid finite elements.
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| 50. |
- Torstensson, Peter, 1981
(författare)
-
Rail Corrugation Growth on Curves
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Short-pitch rail corrugation that may develop on the low (inner) rail on small radius curves causes increased noise and vibration levels on railway networks worldwide. In lack of a generally applicable treatment, track authorities are forced to run expensive rail grinding programs on a regular basis to manage these problems. This thesis presents the first stages in the development of a simulation model for the prediction of rail corrugation growth on small radius curves. By gaining a deeper understanding of the complex dynamic wheel–rail interaction phenomena that lead to corrugation growth, preventive actions may be assessed and implemented. In two separate studies, wear modelling and simulation of dynamic vehicle–track interaction have been considered. A method for the calibration of a wear model using measurement data from a wheel–rail test rig is demonstrated. In terms of worn-off area and profile shape, good quantitative agreement between measured and predicted rail profiles is shown. A time-domain model for the simulation of dynamic interaction between a vehicle and a curved railway track is presented. The simulation model is able to simultaneously capture the low-frequency vehicle dynamics due to curving and the high-frequency track dynamics due to excitation by for example short-pitch corrugation on the low rail. The functionality of the model is demonstrated in several numerical examples. A significant influence of the track and wheelset structural flexibilities on the normal and tangential wheel–rail contact forces is concluded. For a track taken as rigid, the proposed model is validated versus a commercial software. To collect data for later use in the validation of the rail corrugation growth prediction tool, a measurement campaign has been performed. The development of corrugation on a 120 m radius curve on the Stockholm metro was monitored by repeated measurements of rail roughness and train pass-by noise. Within a rail grinding interval of one year, severe short-pitch corrugation was generated on the low rail of the curve with maximum peak-to-peak magnitudes of about 0.15 mm.
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