| 1. |
- Aggestam, Emil, 1992
(författare)
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Comparison of the dynamic response and environmental impact between traditional and innovative railway track systems
- 2023
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Ingår i: International Journal of Rail Transportation. - : Informa UK Limited. - 2324-8386 .- 2324-8378. ; 11:5, s. 685-704
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Tidskriftsartikel (refereegranskat)abstract
- Railways employ a range of different railway track forms. Here, a ballasted track design is compared to three different slab track solutions. The track designs are compared using both a life cycle analysis (LCA) and a methodology for simulation of three-dimensional vertical dynamic vehicle–track interaction, which has been verified versus field measurements. The interaction between vehicle and track is simulated in the time domain using an extended state-space vector approach. For the investigated load cases involving representative wheel and track irregularities, it is concluded that the maximum stress in the concrete parts is, for all designs, below the maximum flexural tensile strength. From the LCA, it is concluded that the production of steel and concrete cause most CO2 emissions, while the CO2 emissions due to maintenance activities such as tamping and rail grinding are only a small part of the overall emissions.
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| 2. |
- Andersson, Evert, et al.
(författare)
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Green Train: concept and technology overview
- 2014
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Ingår i: International Journal of Rail Transportation. - : Taylor & Francis Group. - 2324-8386 .- 2324-8378. ; 2:1, s. 2-16
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Tidskriftsartikel (refereegranskat)abstract
- Green Train (in Swedish, Gröna Tåget) is a research, development and demonstrationprogramme with the overall objective to define an economical, flexible and environmentallyfriendly train concept. The objective is also to develop technology for futurehigh-speed trains for the northern European market, particularly for Scandinavia. Mostof the technology developed is also applicable to other world markets, as well as toslower trains. The programme has covered many important areas, including economy,capacity and market aspects, conceptual design, traveller attractiveness and interiors,travel time, energy efficiency and noise, winter performance, track friendliness and carbody tilt, aerodynamics, electric propulsion and current collection. The programme hasconducted fundamental analysis and research on the different issues as well as designand testing of new technologies. A number of crucial technologies have undergoneperformance and type testing both in lab and on a test train. Experience feedback wasachieved in commercial train service during the period 2006−2013 including harshwinters. This paper summarises a great deal of research and development that has beenperformed in the Green Train programme.
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| 3. |
- Andersson, Evert, et al.
(författare)
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On the environmental performance of a high-speed train
- 2014
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Ingår i: International Journal of Rail transportation. - : Taylor & Francis Group. - 2324-8378 .- 2324-8386. ; 2:1, s. 59-66
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Tidskriftsartikel (refereegranskat)abstract
- Environmental performance is one of the major considerations of future high-speed trains. Two main issues have been closely investigated in the Green Train programme, namely (1) energy use and (2) external noise. Analysis, development and testing in the Green Train programme have focused primarily on speeds up to 250 km/h, although the energy issues have also been studied at top speeds up to 320 km/h. The energy use is estimated for both long-distance trains with few stops and for fast regional services with relatively tight underway stops. These estimations result in an energy use of 46–62 Wh per passenger-km – or 30–40 Wh per seat-km – accounted as electricity taken from the public electric power grid. Improved aerodynamic performance, efficient space utilization, electric regenerative brakes, eco-driving advice and improved energy efficiency in the propulsion system make this possible. Trackside noise has also been analysed and tested in the programme. In order to maintain the same or lower noise level at 250 km/h as at lower speeds with current trains, a number of measures are proposed. These include bogie skirts, wheel absorbers and careful aerodynamic design of the front area and of all protruding objects. In sensitive residential areas, further improvement may be achieved with rail absorbers or low trackside screens.
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| 4. |
- Arvidsson, Therese, et al.
(författare)
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Train running safety on non-ballasted bridges
- 2019
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Ingår i: International Journal of Rail transportation. - : Taylor & Francis. - 2324-8378 .- 2324-8386. ; 7:1, s. 1-22
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Tidskriftsartikel (refereegranskat)abstract
- The train running safety on non-ballasted bridges is studied based on safety indices from the vertical wheel-rail forces. A 2D train- track-bridge interaction model that allows for wheel-rail contact loss is adopted for a comprehensive parametric study on high-speed passenger trains. The relation between bridge response and vehicle response is studied for more than 200 theoretical bridges in 1-3 spans. The bridge's influence on running safety and passenger comfort is differentiated from the influence of the track irregularities. The Eurocode bridge deck acceleration limit for non-ballasted bridges is 5 m/s(2) based on the assumed derailment risk at 1 g from wheel-rail contact loss. This study shows that the running safety indices are not compromised for bridge accelerations up to 30 m/s(2). Thus, accelerations at 1 g do not in itself lead to contact loss and there is potential to enhance the Eurocode safety limits for non-ballasted bridges.
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| 5. |
- Arvidsson, Therese, et al.
(författare)
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Train–bridge interaction : a review and discussion of key model parameters
- 2014
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Ingår i: International Journal of Rail Transportation. - : Taylor & Francis. - 2324-8386 .- 2324-8378. ; 2:3, s. 147-186
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Tidskriftsartikel (refereegranskat)abstract
- Research in the field of train–bridge interaction is reviewed, with a particular focus on the vertical dynamic response of the bridge. The most influential system parameters are identified and discussed, providing a basis from which to establish an appropriate degree of complexity in train and track modelling. A two-level factorial experiment is presented. This is used to highlight the relative influence of train–bridge interaction in the train–bridge model, compared with variations in other key parameters. We distinguish those parameter combinations in the train–bridge system that lead to a significant reduction in bridge response due to the train–bridge interaction. The present survey fills an important gap in our existing knowledge by synthesising conclusions from the vast literature on train–bridge interaction. Moreover, the knowledge is related to the European design code’s guidelines for dynamic bridge analysis. The conclusions are summarised to give a rough guidance on modelling choices for train–bridge interaction systems.
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| 6. |
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| 7. |
- Fröidh, Oskar, et al.
(författare)
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Capacity for express trains on mixed traffic lines
- 2014
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Ingår i: International Journal of Rail Transportation. - : Taylor & Francis Group. - 2324-8386 .- 2324-8378. ; 2:1, s. 17-27
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Tidskriftsartikel (refereegranskat)abstract
- Mixed traffic with large speed differences between fast and slower trains consumesmore capacity and makes the system sensitive to disruptions. This article focuses onadequate train configuration for increasing the top speed for express trains like theGreen Train and how that affects capacity on lines with heterogeneous traffic.Microscopic simulation of a future timetable selected by criteria revealed by analyticaltimetable analysis for a chosen structure of services combines the advantages of twomethods and makes it possible to reveal relevant characteristics for different alternatives.Punctual short stops through better train layout and skip-stop operation forregional trains are a few of the measures that are shown to have compensating effectsfor the increase in capacity utilisation and can reduce disruptions. Although it ispossible to reduce the perturbations by means of different measures, the basic problemwith mixing fast and slower trains on the same line still remains.
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| 8. |
- Fröidh, Oskar, et al.
(författare)
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Green Train concept and interior design
- 2014
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Ingår i: International Journal of Rail Transportation. - : Taylor & Francis Group. - 2324-8378 .- 2324-8386. ; 2:1, s. 28-39
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Tidskriftsartikel (refereegranskat)abstract
- In the Green Train research programme, the objective is to develop an attractive trainconcept in the form of a concept proposal based on economic assessments. Green Trainis to be an attractive express train for both business and leisure-time travellers. Highstandards of comfort can be motivated by passengers’ willingness to pay. One fundamentalidea is the wide carbody for services in Scandinavia to achieve lower total costsfor train traffic than a carbody with a normal, quite narrow European continentalprofile. The trains are thereby made shorter and 2 + 3 seating arrangements areoptimised for optimal comfort. Another principle is that the train must be designedto allow punctual station stops, also during periods of peak load. Boarding andalighting must take place within very tight margins, which means that doors, entrancesand luggage racks must be in well-considered locations and correctly dimensioned.
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| 9. |
- Herbst, A H, et al.
(författare)
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Aerodynamic prediction tools for high-speed trains
- 2014
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Ingår i: International Journal of Rail transportation. - : Taylor & Francis. - 2324-8378 .- 2324-8386. ; 2:1
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Tidskriftsartikel (refereegranskat)abstract
- With high-speed trains, the need for efficient and accurate aerodynamic prediction tools increases, since the influence of the aerodynamics on the overall train performance raises. New requirements on slipstream velocities and head pressure pulse in the revised Technical Specification for Interoperability (TSI) for train speeds higher than 190 km/h are more challenging to fulfil for wide-body trains, like the Green train concept vehicle Regina 250, as well as higher trains, like double-deck trains. In this paper, we give an overview of the results from a project within the Green train programme, where the objective was to increase the knowledge on slipstream air flow of wide body trains at high speeds, to understand the implications of the new requirements on the front shape and to develop a prediction methodology in order to take this into account early in the design cycle. In addition, the front design was in parallel optimized with respect to head pressure pulse and drag.
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| 10. |
- Khajehei, Hamid, 1987-, et al.
(författare)
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Prediction of track geometry degradation using artificial neural network: a case study
- 2022
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Ingår i: International Journal of Rail transportation. - : Taylor & Francis. - 2324-8378 .- 2324-8386. ; 10:1, s. 24-43
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study has been to predict the track geometry degradation rate using artificial neural network. Tack geometry measurements, asset information, and maintenance history for five line sections from the Swedish railway network were collected, processed, and prepared to develop the ANN model. The information of track was taken into account and different features of track sections were considered as model input variables. In addition, Garson method was applied to explore the relative importance of the variables affecting geometry degradation rate. By analysing the performance of the model, we found out that the ANN has an acceptable capability in explaining the variability of degradation rates in different locations of the track. In addition, it is found that the maintenance history, the degradation level after tamping, and the frequency of trains passing along the track have the strongest contributions among the considered set of features in prediction of degradation rate.
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