Swedish Railway Research Articles

The impacts of weather on railway infrastructure in Sweden

ABSTRACT In this paper, we estimate the vulnerability of railway infrastructure, switches, signals, tracks, and catenaries to different weather conditions, temperature, precipitation, snow depth, and wind speed across the entire Swedish railway network between 2006-2020. Using a method to quantify the fault rate we establish thresholds that can be useful for identifying areas of concern for operations. Results reveal that high or low temperatures have a noticeable impact on the fault rates for switches, tracks, and catenaries. High levels of precipitation are associated with higher fault rates across tracks and catenaries. Snow depth has an influence on fault rates for switches and tracks, and high wind speeds are associated with higher fault rates for tracks and catenaries. Finally, signals were found to be the most resilient asset. When comparing two dominant climate zones, notable differences were only found for track asset vulnerability.

The impact of railway incidents on train delays: A case of the Swedish Railway Network

A foreseeable challenge with a substantial increase in railway mode share will be how to uphold punctuality. Higher volumes of train traffic will result in timetables that are more sensitive to disruptions; whose severity and frequency is also expected to increase in light of greater asset utilization and climate change. This calls for a definitive understanding of the relationship between incidents and train delays as a prerequisite to developing robust timetables and disruption management strategies. In this paper we propose a novel framework for quantifying the impact of railway incidents on train delays. Using a case of the Swedish Railway Network, we compare the impact of different incidents on train delays. The impact of delay is defined as a factor of the incident rate, exposure rate, delay rate and historical average delay minutes per incident. A logistic model that estimates the probability of delay for any train, in the event of a failure, is also developed. Snow on track was established as most critical, resulting in the highest normalized delay minutes per train and the largest increase in the odds of delay for individual trains. The proposed framework & approach can be applied to other networks.

Weaponized disinformation spread and its impact on multi-commodity critical infrastructure networks

The well-publicized disinformation campaigns surrounding recent elections, pandemic vaccination adoption, as well as supply-chain disruptions and shortages have made historical problems of disinformation more apparent. When disinformation targets transportation infrastructure, supply chains can be disrupted, resulting in commodities shortages such as food and fuel, consequently jeopardizing the health and safety of communities. This research proposes an integrated epidemiological-optimization model that quantifies the impacts of weaponized disinformation on infrastructure networks that transport multiple commodities. The model aims to minimize the overall weighted shortage of commodities caused by different disinformation spread rates. Results show that disinformation weaponized against transportation infrastructure, potentially targeting a particular geographical region or a particular commodity, can have wide-ranging impacts across different commodities. The proposed model is applied to the multi-commodity Swedish railway network carrying 14 different categories of commodities over 1360 supply and demand nodes.

Meta-Heuristic for inserting a robust train path in a non-cyclic timetable

ABSTRACT Many freight trains depart Swedish marshalling yards before or after their planned departure times. Today, a deviating departure time is allowed if no conflicting train path can be found a few stations ahead. This increases the risk that the train might be delayed to its destination and cause delays to other trains. We present a meta-heuristic that modifies a timetable by adding a train path (for our freight train) and, if necessary, adjusting surrounding train paths. The aim of the insertion of the additional train path and the adjustments of the existing ones is to obtain a large bottleneck robustness, that is, the largest possible minimal temporal distance to any other train in the timetable. We provide experimental results for a Swedish railway stretch with a non-cyclic timetable and heterogeneous traffic. We show that we quickly add a train path, while improving the robustness of the timetable.

Challenges of replacing train drivers in driverless and unattended railway mainline systems—A Swedish case study on delay logs descriptions

Currently, the challenges of driverless or unattended train operation have not been described in detail and are often grouped into one category. This paper contributes to filling a knowledge gap regarding the roles of the train driver about the potential use of automatic train operation (ATO) on high grade of automation (GoA) levels. The results contribute to a better understanding of the challenges with driverless or unattended train operation to support strategies on how to utilize ATO on a wider range of trains than is presently the case. We use the Swedish railway network as a case study and delay logs written by train dispatchers for 2019. Our research quantifies how often unplanned events occur in which the train driver is needed, and the role of the train driver in solving these problems. In addition to this we elaborate on existing GoA levels definitions and propose a revised model that highlights more aspects of the train drivers’ roles. We have identified six categories in which an action by the driver is required: Detect, Report, Inspect, Adjust, Manage passengers, and Respond to train orders. The study illustrates some of the challenges with driverless or unattended train operation, and points to the need to develop strategies not only for the driving aspects of ATO but also for the more general technical operational management of rolling stock in high GoA levels.

Field Observations of Water and Ice Problems in Railway Tunnels from a Maintenance Perspective

Abstract During the winter season, ice causes major problems in many Swedish railway tunnels. Ice, rock and shotcrete in the roof and on the walls may come loose and fall down, installations and cables can break due to ice loads and the tracks can become covered with ice. To maintain safety and prevent traffic disturbances, many tunnels require frequent maintenance. The removal of ice, loose rock and shotcrete is expensive and potentially risky work for the maintenance workers. To reduce maintenance costs, it is important to improve our knowledge of frost penetration inside tunnels and investigate the effect of ice pressure and frost shattering on load-bearing constructions. The aim of this investigation was to gather information about the problems caused by water leakage and its effect on the degradation of a rock tunnel when subjected to freezing temperatures. There are many factors that determine whether frost or ice formations will appear in tunnels. To collect information on ice formation problems, field observations were undertaken in five of Sweden’s railway tunnels between autumn 2004 and summer 2005. For one of the tunnels, follow-up observations also took place in March during the years 2005, 2006 and 2007. Keywords: Railway tunnel, Field observations, Ice formation, Frost shattering, Maintenance, Degradation of rock and shotcrete, Cold climate.

On the low temperature tribological behaviour of brake block materials for railway applications under dry and icy conditions

Incidents in the Swedish railway have been observed where a significant and sudden loss of brake performance occurs in winter conditions, on trains equipped with composite tread brake blocks (CBB). There is a necessity to establish test methods that can be used for the evaluation of brake materials under well-controlled laboratory conditions, to facilitate an understanding of the friction mechanisms between brake block and steel wheel. This work sought to characterise the tribological behaviour of different CBB materials at room temperature and −15 °C, focusing on understanding the materials response with and without presence of ice in the contact, as well as the effect of temperature on the tribological behaviour. A pearlitic cast iron brake block was used as a reference and four CBB materials were investigated, two organic and two sintered. The sintered CBB showed similar friction coefficient to the reference material and higher than the organic CBB, both at room and at low temperature. This was also seen when ice was formed on the wheel steel counter surface at −15 °C. Higher wear was observed for the sintered CBB compared to the organic CBB. The results suggest that sintered CBB can provide higher friction under winter conditions compared to organic CBB.

Neither market nor hierarchy—coordination costs in the allocation of track capacity in the Swedish railway network

AbstractTransaction costs have been an issue since the advent of the deregulation of the European railway markets in the 1990s. Transaction cost economics received renewed attention in research on the deregulated railway markets in the EU after the publications of two influential reports in the early 2010s.In this article, we develop a model that enables classification and measurement of transaction costs and other coordination costs in deregulated markets. This model is then used to analyze the costs of path allocation in the Swedish railway sector and to compare the results with findings in previous research. We also discuss the economic rationale of the distribution of coordination costs among the involved parties.Our key empirical findings are that the total coordination costs in the Swedish market‐mimicking path allocation process are as low as or lower than the most cost‐efficient market coordination processes studied in railway markets, and that the state administrations take on nearly all the coordination costs in order to minimize the effects of opportunism, rent‐seeking and information impactedness. Another finding is that the size of the coordination costs found by different studies seems to be dependent on whether a bottom‐up or a top‐down approach is used.

The Effects of Train Passes on Dwell Time Delays in Sweden

Railway traffic is growing, resulting in a highly interconnected train network. Due to the interdependence between trains’ activities, a better understanding of train passes and their effects can ensure dispatching decisions made have minimum risk of delays. The impacts of train pass on dwell time delays were investigated using historical Swedish railway operation data. Three scenarios were considered by combining the scheduled and actual operations: passes that happened as scheduled, unscheduled passes that happened in operation, and scheduled passes that were cancelled. A logistic regression model was used to explore the effects of these passes on delays. The findings show that train passes rarely occurred as scheduled, more frequently they are cancelled or unscheduled. This implies that some adjustments are required to assure the timetable’s feasibility. This study also found that the odds of delays for the cancelled pass was about 9.80 times lower than scheduled pass but 2.6 times more often for an unscheduled pass than a scheduled pass. The different types of train passes were quantified using an odds ratio to make comparisons easier for dispatching decision-making. The approach used in this study can be extended to other types of train movements, such as the meeting of trains, as well as other delay-influencing factors.

Service-based business models in the Swedish railway industry

PurposeThe purpose is to describe new business opportunities within the Swedish railway industry and to support the development of business models that corresponds with the needs and requirements of Industry 4.0, here denoted as Service Management 4.0.Design/methodology/approachThe study is an in-depth and descriptive case study of the Swedish railway system with specific focus on a railway vehicle maintainer. Public reports, statistics, internal documents, interviews and dialogues forms the basis for the empirical findings.FindingsThe article describes the complex business environment of the deregulated Swedish railway industry. Main findings are in the form of identified business opportunities and new business model propositions for one of the key actors, a vehicle maintainer.Originality/valueThe article provides valuable understanding of business strategy development within complex business environments and how maintenance related business models could be developed for reaching Service Management 4.0.

Environmental fate of glyphosate used on Swedish railways — Results from environmental monitoring conducted between 2007–2010 and 2015–2019

Glyphosate herbicides are widely relied upon by European railway operators for controlling vegetation growing on railway tracks. In Sweden, concentrations of glyphosate and its main degradation product AMPA have been monitored in the groundwater close to railways during two monitoring periods: between 2007–2010 and 2015–2019. In total, 603 groundwater samples from 12 different monitoring sites and 645 soil samples from 5 of these sites were analyzed. Glyphosate and AMPA were detected in 16% and 14%, respectively, of groundwater samples taken from directly beneath the track, with concentrations exceeding the EU groundwater quality standard of 0.1 μg/L in 6 and 4% of the cases, respectively. The highest concentrations detected in single samples were 7 μg glyphosate/L and 1.1 μg AMPA/L. However, further horizontal spread in the groundwater zone appeared to be limited as glyphosate and AMPA were only detected in 1–3% of the groundwater samples taken from outside the track area itself, and since no difference was seen between water from reference and down-gradient wells. In the autumn of 2018, higher concentrations were detected in the groundwater from beneath 3 out of the 5 then active monitoring sites and a possible explanation is that the unusually hot and dry summer of 2018 limited degradation, thus leading to an increased susceptibility of leaching. The contents of glyphosate and AMPA in soil samples from three of the sites were very low (average < 0.05 mg/kg in soil from 0 to 30 cm), indicating that they were only sprayed to a limited degree, whereas the contents from two of the test sites were in line with what would be expected based on the used dose and a predicted half-life of about 4 ± 2 months (average 0.22–0.84 mg/kg). No signs of accumulation of glyphosate in the railway ballast over time were observed.

Remaining useful Life Improvement for the Mining Railcars under the Operational Conditions

ABSTRACT The large tonnage mines use railway transportation as a system for mineral transportation. The rolling stock health condition study and improvement not only reduce the lifecycle cost of the assets but also ensures safe, reliable, punctual, and efficient transportation. The remaining useful life estimation is an efficient approach to condition-based maintenance, prognostics, and health management. This paper aims to predict the remaining life of a mining rolling stocks in the presence of operational environmental effects. In this study, the operation and failure data were obtained from Malmbana, LKAB, Sweden, a Swedish Railway Company, considering the effective operational factors. The failure behaviour of the railcar was evaluated and then the proportional hazard model was used to estimate the conditional reliability functions and accordingly the remaining useful life at the various initial survival time. Finally, the reliability-based time interval is applied to plan the maintenance operations. Results of this study show that the operator’s skill level and the maintenance quality had a significant influence on the reliability performance. By considering the proposed PM plan according to the desired reliability level, the remaining lifetime of the rolling stock will be improved by 78.10%, on average.

Statistical analysis of departure deviations from shunting yards: Case study from Swedish railways

Departure deviations from shunting yards impact the reliability of rail freight services and the punctuality of a railway network. Therefore, the statistical analysis of these deviations are necessary for improving the operation of trains in mixed-traffic networks. In our paper, we conduct a detailed statistical analysis of departure deviations considering individual shunting yards characteristics. We use a large freight train delay dataset comprising 250,000 departures over seven years for the two largest shunting yards in Sweden, comparable to other medium-sized shunting yards in Europe. To find the probability distribution of departure deviations, we compare four distribution functions including the exponential, the log-normal, the gamma, and the Weibull according to the maximum likelihood estimates and results of the Anderson-Darling goodness of fit test. In our experiments, we show that the log-normal distribution fits best for delayed departures across both shunting yards, and for early departures at one of them, whereas the gamma distribution fits best for early departures at the other yard. For the temporal delay distribution, we find that fluctuations in the network usage impact the percentage of delayed departures across hours and weekdays, but not across months or years. In addition, we find that freight trains are mostly delayed in the winter. In the case of hourly delayed departures, we demonstrate that a shunting yard involved with domestic traffic showed a negative correlation between delayed departures and the network usage, whereas an international shunting yard did not, which indicates individuality in shunting yard operations impact shunting yard-network interactions. Our findings mainly contribute to better understanding of departure deviations from shunting yards, thus enhancing the operations and capacity utilization of shunting yards. Moreover, delay distributions can be beneficial in handling delays in traffic management models as well as enhancing the outputs of freight train simulation models.

Prediction of track geometry degradation using artificial neural network: a case study

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.

Temperature Flows in Railway Tunnels: Field Measurements of Frost Penetration

Even though extensive pre-grouting is carried out during the construction of tunnels, certain leakages and drips remain. These remaining leakages are remedied by a combination of post-injection and drainage measures with, for example, frost insulated drain mats, whose function is to prevent the cold tunnel air from reaching a leakage spot and causing water to freeze. Despite these measures, some water may still enter the tunnels and cause problems during winter with ice formations and frost shattering. Icicles, ice pillars and ice-covered roads and railway tracks require constant maintenance. If ice occurs in the fracture network close to the tunnel contour or in the interface between the rock and shotcrete, it can cause degradation of the load-bearing capacity of the tunnel and fall-outs of both materials. In tunnel sections with water leakage problems it is common to protect the load-bearing structure from freezing with insulated drainage systems. To determine where along the tunnel efforts must be made to prevent ice formation, the temperature conditions of tunnels must be investigated. This article presents parts of the results from field measurements in two Swedish railway tunnels. The measurements involves monitoring of air and rock temperatures, air pressure and air velocity. Keywords: Frost penetration, ice formation, frost shattering, temperature measurement, maintenance, railway tunnel.

Railway timetabling: a maximum bottleneck path algorithm for finding an additional train path

We present an algorithm to insert a train path in an existing railway timetable close to operation, when we want to affect the existing (passenger) traffic as little as possible. Thus, we consider all other trains as fixed, and aim for a resulting train path that maximizes the bottleneck robustness, that is, a train path that maximizes the temporal distance to neighboring trains in the timetable. Our algorithm is based on a graph formulation of the problem and uses a variant of Dijkstra’s algorithm. We present an extensive experimental evaluation of our algorithm for the Swedish railway stretch from Malmö to Hallsberg. Moreover, we analyze the size of our constructed graph.

Entrepreneurial relationship marketing in 19th century India – The case of railway contractor Joseph Stephens

Our article is based on the diaries of Joseph Stephens, a 19th century Swedish railway contractor in British India. The Stephens’ diaries, discovered in 2008, are the only one of their kind, offering an insight into the life of a railway contractor from that era. The diaries reveal a web of networks and relationships that helped Stephens achieve success as a small-scale railway contractor. We use the theoretical lens of Gummesson’s entrepreneurial relationship marketing to analyse Stephens’ network of social and work relationships and find a connection between his networks and Gummesson’s framework. We contribute to literature by presenting a different perspective on railway contractors from that period and propose that business practices of the past can be studied vis-à-vis contemporary theories of entrepreneurship and marketing.

Railway network design and regional labour markets in Sweden

Investment in railways, and transport infrastructure in general, are often motivated because they are believed to improve peoples’ accessibility to jobs. By linking together and increasing the size of labour markets, the matching between individuals and jobs is improved, and the productivity increases. Communities and municipalities lobby for investments that lead to higher accessibility and those that are successful often see inflows of people as a consequence. This paper looks at the entire Swedish railway network, at the level of service of each station and at the connectivity among stations during the morning peak hour, considering different time bands. Associations between job accessibility levels and socio-demographic features are explored and disclosed, looking at the longitudinal impacts of railway investments over 4 years (from 2011 to 2014) on annual wages. Estimating a fixed effects model, very small effects on wages have been found with the increase in the number of jobs around accessible rail stations. These preliminary results indicate that additional jobs along the rail network seem to have a marginal effect. The findings of this analysis, if communicated to planners, may assist them in assessing the effects of future railway measures to implement over the Swedish territory.

Resonance and cancellation phenomena in two-span continuous beams and its application to railway bridges

The objective of this study is to evaluate the vibratory response of two-span continuous beams subjected to moving loads and, in particular, to investigate the maximum resonance and cancellation of resonance phenomena. The main practical interest is the evaluation of the maximum acceleration response in railway bridges, which is one of the most demanding Serviceability Limit States for traffic safety according to current regulations. Two-span continuous bridges, in their simplest version (i.e. uniform identical spans), present antisymmetric and symmetric modes with closely spaced natural frequencies, leading to a more involved dynamic behaviour than that of simply-supported bridges. First, the free vibration response of a Bernoulli-Euler two-span beam after the passage of a single load at constant speed is formulated analytically, and non-dimensional speeds leading to cancellation or maximum response in free vibration are obtained for each mode. Then, these conditions are equated to resonant speeds induced by equidistant load series, and span length-to-characteristic distance ratios causing cancelled out resonances, or remarkably prominent ones, are obtained. Based on the previous derivations, a methodology for detecting which could be the most aggressive trains for a particular structure based on pure geometrical considerations is discussed. Finally, the applicability of the theoretical derivations is shown through the numerical analysis of two real bridges belonging to the Swedish railway network.

Nowcast models for train delays based on the railway network status

Switches and crossings (S&C) or turnouts are one of the important systems in the Swedish railway traffic maintenance planning. For immediate diverting of the trains, they need to be predict the working condition for short time duration, also known as nowcasting and for long time duration, also known as forecasting. The prediction of the condition of turnout is useful for traffic planning without disrupting to the traffic. Hence, the main purpose of this paper is to predict the condition of S&Cs for shorter and longer duration. In order to achieve it, at first, statistical analysis is carried out to find the root causes of failures. Secondly, non-homogenous Poisson process is applied to nowcast and forecast the working condition. The results of this study will guide the train dispatchers to plan the train timetable according the present traffic.