2,899 research outputs found

    A review of key planning and scheduling in the rail industry in Europe and UK

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    Planning and scheduling activities within the rail industry have benefited from developments in computer-based simulation and modelling techniques over the last 25 years. Increasingly, the use of computational intelligence in such tasks is featuring more heavily in research publications. This paper examines a number of common rail-based planning and scheduling activities and how they benefit from five broad technology approaches. Summary tables of papers are provided relating to rail planning and scheduling activities and to the use of expert and decision systems in the rail industry.EPSR

    The Maraca: a tool for minimizing resource conflicts in a non-periodic railway timetable

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    While mathematical optimization and operations research receive growing attention in the railway sector, computerized timetabling tools that actually make significant use of optimization remain relatively rare. SICS has developed a prototype tool for non-periodic timetabling that minimizes resource conflicts, enabling the user to focus on the strategic decisions. The prototype is called the Maraca and has been used and evaluated during the railway timetabling construction phase at the Swedish Transport Administration between April and September 2010

    Generation of the transport service offer with application to timetable planning considering constraints due to maintenance work

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    Line planning is an important step in strategic timetable planning in public transport. In this step the transport offer for the customer is generated by the public transport operator, whereby the resulting costs for the operator should be as deep as possible. Mathematical models for line planning allow to create optimized line plans quickly. Planners can use these models to rate and select different alternatives. This is particularly valuable under the aspect of increasing maintenance and construction tasks of the railway infrastructure. We show, that in this case, it is possible to create functional requirements for automated timetable creation from the result of line planning step. The practical use of the involved models is illustrated by a real application example

    Adaptive Railway Traffic Control using Approximate Dynamic Programming

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    Railway networks around the world have become challenging to operate in recent decades, with a mixture of track layouts running several different classes of trains with varying operational speeds. This complexity has come about as a result of the sustained increase in passenger numbers where in many countries railways are now more popular than ever before as means of commuting to cities. To address operational challenges, governments and railway undertakings are encouraging development of intelligent and digital transport systems to regulate and optimise train operations in real-time to increase capacity and customer satisfaction by improved usage of existing railway infrastructure. Accordingly, this thesis presents an adaptive railway traffic control system for realtime operations based on a data-based approximate dynamic programming (ADP) approach with integrated reinforcement learning (RL). By assessing requirements and opportunities, the controller aims to reduce delays resulting from trains that entered a control area behind schedule by re-scheduling control plans in real-time at critical locations in a timely manner. The present data-based approach depends on an approximation to the value function of dynamic programming after optimisation from a specified state, which is estimated dynamically from operational experience using RL techniques. By using this approximation, ADP avoids extensive explicit evaluation of performance and so reduces the computational burden substantially. In this thesis, formulations of the approximation function and variants of the RL learning techniques used to estimate it are explored. Evaluation of this controller shows considerable improvements in delays by comparison with current industry practices

    Terrorist Threat Mitigation Strategies for the Railways

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    Terrorism is an ever-present threat that is becoming more prevalent in today’s society. The railway has always been a favourable target for terrorists due to the high volume of people that utilise it, as well as the vital services it provides to the nation. The railway is expanding and this will likely result in it becoming increasingly vulnerable to attack, unless new mitigation solutions are devised. In this paper risk assessment analyses by a software package conducted on different sections of the railway station provided insight into the present vulnerabilities. Mitigation solutions were devised to abolish these weaknesses in the system, to avoid terrorist exploitation. They were then evaluated to establish a workable solution: a modified version of the Thales Smart Corridor. This workable solution should be implemented across the nation to ensure passenger and rail infrastructure protection

    Strategies for maintenance management of railway track assets

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    M.Ing. (Engineering Management)Abstract: Population growth and environmental issues are revitalizing the railway sector in a tremendous way. An increase in frequency of passenger traffic and rising loads of freight trains has an impact on dynamic railway track properties and components thereof. The challenge from the railway fraternity is to rise to the challenge by ensuring a safe, reliable and affordable mode of transport. The purpose of this research is to investigate the capacity needed to meet demand by maintaining the track components of the railway infrastructure cost effectively. The railway track is the most critical in terms of safety, influence on maintenance costs, availability and reliability of the train service. Profillidis (2012) highlights the fact that track maintenance expenses represent a significant percentage of total railway infrastructure expenses. In literature, different maintenance strategies, approaches and concepts are discussed in light with arguments raised by different scholars and researchers. The main research methodology utilised was the case study on maintenance strategies from different countries where data was mostly available. The reason for the chosen method was to standardise the research method across different countries as this made it easy to obtain the findings and arrive at recommendations of the research. The broader findings from different maintenance strategies were that the track maintenance approach still has to evolve from working in silos to working in a system that acknowledges that decisions taken from other departments can affect the quality of maintenance in future. The deterioration of the track system is mostly affected by the initial quality of the railway track after commissioning due to workmanship and track design, maintenance approach, type of rolling stock tonnages, speed of rolling stock, and environmental related issues. Design phase of the track acknowledges the systems thinking approach for quality and structural integrity. However, more can still be done to adopt approaches that foster inter-departmental coordination in the maintenance phase of the railway track asset lifecycle. Transnet faces a challenge of fulfilling its obligation by providing quality and cost effective maintenance to increase the reliability, affordability, availability and safety of its infrastructure with the ever-increasing freight volumes. The traditional approach of maintaining railway track assets does not bring in required outcomes that ensure high quality and cost effective maintenance as required by high intensity asset utilisation. Data collected from the..

    Delays and Timetabling for Passenger Trains

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    Travel by train has increased steadily in Sweden the last 30 years. The pace has been about two to three percent per year, and we now have twice as many passengers. With growing awareness of the changing climate, the pace is increasing further. A problem that affects both passengers and businesses in Sweden is train delays. One way to describe these is as the share of trains that arrive less than six minutes delayed. About 90% of trains in Sweden meet this standard and have done so for many years. In a way this is impressive, since there are now many more trains. Unfortunately, this also means that more and more passengers are affected by delays. This leads to irritation, threatens the shift of traffic to railways, and costs a lot for society. More trains must arrive on time. This thesis shows that delays are mostly caused by small disturbances – up to a minute or two. Over long journeys, these small disturbances accumulate and sometimes cause quite big delays. These delays mostly occur at stations, where the trains stop, but are then unable to continue on time. It is difficult to say exactly what causes these small disturbances, but the time that the trains are supposed to be at stations – the dwell times – are often too short. Another pattern is seen between delays and weather: if it is either warm or cold, delays increase rapidly. And while winter and snow return every year, they still cause major disruptions. The thesis holds a few suggestions to reduce delays. One is platform markings that show where the trains will stop, where the doors will be, and where the passengers should wait. This is an easy and affordable way to speed up the stops, so that the trains depart on time. Another measure is to remove switches. Then there are fewer parts that can fail, and those that remain can be maintained to a higher standard. A third way is to adapt the railway, so that it better withstands the weather variations of today, and the climate changes of tomorrow. Something that has been done in other countries is to shade and air-condition electronics and signals along the railway. Then the components to not overheat, and more trains run on time. Many things can also be done with timetables, so that more trains run on time, without a rise in costs. More of the planning can be automated. Then more time can be spent on giving trains appropriate dwell times. Infrastructure managers should also do more to evaluate and improve the rules and guidelines that govern timetabling. In this way we can improve timetables gradually from year to year, with fewer and fewer delays as a consequence. These suggestions do not solve all of the railway’s issues, but they would lead to many more trains arriving on time
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