Main Line System Research Articles

Trackside sensors in unattended train mainline systems - A case study of alarm logs from Sweden

Implementing unattended train operation on the mainline could make the railway more competitive by reducing operating costs since there will be no staff onboard the train. This will, however, lead to new challenges. One of those challenges is how to deal with manually controlling trackside sensor alarms. In this paper, we study all trackside sensor alarms (hotbox/hotwheel and wheel damage) in Sweden for one year (2019) to study their frequency and context. The results show that freight trains have 10 times higher frequency for alarms per train kilometer than passenger trains. There are statistically significant seasonal and climate zone differences. The highest frequency of trackside alarms occurs in wintertime in the colder climate zone. The results can be used in the development of unattended train operation support systems on the mainline.

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.

Research on Design Method of Intelligent Operation and Maintenance System for Secondary Equipment in Intelligent Substation

Abstract Smart substations are an important part of establishing a strong smart grid. In view of the large variety of secondary equipment in the current power system, the rapid increase in quantity, and the complex working conditions of the current power supply company maintenance classes to inspect substations, a design method for the intelligent operation and maintenance system of secondary equipment in smart substations is proposed in this article. First, the intelligent operation and maintenance system architecture of the secondary equipment of the smart substation is established via Redis and ActiveMQ technologies. Then the system function module model is established. Finally, taking a 220kV substation in a certain area of southern China as an example, a new type of intelligent substation secondary equipment intelligent operation and maintenance system was installed and connected to the main line system, and the effectiveness of the proposed method was verified.

A continuous model for coordinated pricing of mixed access modes to transit

The land-use pattern for many cities is a central business district surrounded by sprawling suburbs. This pattern can lead to an inefficient and congestion-prone transportation system due to a reliance on automobiles. This is because high-capacity transit is inefficient in low-density areas where insufficient travelers can access transit. This also poses an equity concern as the monetary cost of faster and more expensive travel disproportionately burdens low income travelers, especially when fixed congestion pricing is imposed. This paper presents a deterministic approximation of a discrete choice model for mixed access and mainline transportation modes, meaning that travelers may use different modes to access a mainline system, such as transit. The purpose is to provide a tractable computationally efficient model to address the first/last mile problem using a system-wide pricing policy that can account for heterogeneous values of time; a problem that is difficult to solve efficiently using a stochastic model. The model is structured for a catchment area around a central access point for a mainline mode, approximating choice by comparing modal utility costs. The underlying utility model accommodates both fixed prices (e.g., parking, fixed tolls, and fares) and distance-based unit prices (e.g. taxi fare, bike-share, and distance tolls) that may be set in a coordinated way with respect to value of time. Using numerical analysis to assess accuracy, the deterministic model achieved results within 3% of a stochastic logit-based model, and within 7% of measured values. The optimization of prices using the final model achieved a 22% reduction in generalized travel time and a 30% improvement in the Gini inequity measure from 0.2 to 0.14.

A Continuous Model for Coordinated Pricing of Mixed Access Modes to Transit

Abstract The land-use pattern for many cities is a central business district surrounded by sprawling suburbs. This pattern can lead to an inefficient and congestion-prone transportation system due to a reliance on automobiles. This is because high-capacity transit is inefficient in low-density areas where insufficient travelers can access transit. This also poses an equity concern as the monetary cost of faster and more expensive travel disproportionately burdens low income travelers, especially when fixed congestion pricing is imposed. This paper presents a deterministic approximation of a discrete choice model for mixed access and mainline transportation modes, meaning that travelers may use different modes to access a mainline system, such as transit. The purpose is to provide a tractable computationally efficient model to address the first/last mile problem using a system-wide pricing policy that can account for heterogeneous values of time; a problem that is difficult to solve efficiently using a stochastic model. The model is structured for a catchment area around a central access point for a mainline mode, approximating choice by comparing modal utility costs. The underlying utility model accommodates both fixed prices (e.g., parking, fixed tolls, and fares) and distance-based unit prices (e.g. taxi fare, bike-share, and distance tolls) that may be set in a coordinated way with respect to value of time. Using numerical analysis to assess accuracy, the deterministic model achieved results within 3% of a stochastic logit-based model, and within 7% of measured values. The optimization of prices using the final model achieved a 22% reduction in generalized travel time and a 30% improvement in the Gini inequity measure from 0.2 to 0.14.

Spatial/Political Relations and the Uncertainty of Regional Railways

The recent history of Australia’s regional railways indicates a degree of government policy inertia, constrained by our system of governance as well as reliance on competition as a solution to inefficiencies in transport. The approach taken by governments to reforming regional railway systems was placed under the same blanket of competition policy-derived measures: creating competing businesses by way of privatisation and “open access” to tracks, or at least allowing competitors for the government’s operator, in the case of Queensland, onto the states’ tracks. An inquiry into the condition of Victoria’s regional network has indicated that, at best, this approach has been inadequate. During 2008, the NSW Government implicitly acknowledged the shortcomings of competition-dependent policy by restoring some assets to public ownership. It also appears that insufficient consideration was given to the spatial arrangement of the main line and regional systems, which, in the light of experience in Canada and the USA, appear to be better treated separately due to different conditions and constraints on branch lines, and the greater productivities available on main lines. Following some analysis of the branch line system of NSW, this paper attempts to propose that a political/geographical analysis in company with the basic economics of railway operation would point towards different plans for branch and main line systems, and avoid the conditions now threatening regional freight railways. Such plans should be accompanied by a different approach to regional-central government relations and reconsideration of Commonwealth, state and local government roles in regional transport development. This paper mentions the recent history of local-central government relations in Australia, highlighting the present difficulties faced by local interests in developing rail services for local industrial development. It places regional transport issues in that context before suggesting some ways to give greater certainty to sustainable transport options, both passenger and freight, for regional Australia.

A procedure to design the mainline system in natural gas networks

With the start up of West–East Natural Gas Transmission Project, the construction of natural gas-pipeline will enter on a new era in China. The development tendency will be towards large-diameter, high-pressure and long-distance for natural gas-pipelines. Correspondingly, the life cycle cost of natural gas-pipeline networks is increasing gradually. The mainline system is a vital part of natural gas network systems. The investment required for the mainline system is enormous, usually accounting for 80% of the total investment for this system. In general, the investment required for a gas-pipeline depends on its operating parameters. Therefore, based on the characteristics of gas networks, optimization for investment becomes indispensable to gas networks design. A comprehensive and optimal mathematic model of a gas networks system is established in this paper which considers all the factors influencing the total investment of a gas networks system (e.g. pipe diameter, thickness, pressure, length, compression ratio, etc). From the standpoint of the characteristics of a model comprising both continuous and discrete variables, a new methodology, rank-optimization, is presented. On the basis of this model, a simple and visual high-pressure networks optimization program has been compiled. Furthermore, the developed optimization program has been applied to a practical project and the effects of operating parameters on the total investment have been analyzed. The simulation model in this paper is shown to be an effective method to solve optimization on mainline system in high-pressure gas networks.

Improving Queue Size Estimation for Minnesota's Stratified Zone Metering Strategy

Stratified zone metering (SZM), a successor of zone metering, was recently implemented in the United States in the Twin Cities. SZM not only restricts metering rates subject to the freeway capacity constraints but also limits the on-ramp waiting time to a predetermined threshold. In SZM, accurate queue size estimation is crucial because inaccurate queue size can violate the maximum wait time constraint or reduce the service quality of the main-line system. Currently, a uniform and pre-calibrated regression equation is adopted for ramp queue size estimation for all ramps. It has been verified that such an estimation method may lead to outstanding estimation errors for ramp queues. In this paper, different ramp queue estimation algorithms are proposed for ramps with different categories, depending on the counting errors of queue and passage detectors. For ramps with minor counting error, queue size is estimated on the basis of flow conservation. For ramps with significant counting error on passage detectors but minor counting error on queue detectors, the flow conservation model can still be applied, but the traffic counts of passage detectors are replaced by the “green counts,” which are calculated by the ramp metering rate. For ramps with significant count errors from both queue and passage detectors, a Kalman filtering model is adopted. To verify the proposed methods, surveillance video data were used to compare actual and estimated queue sizes. Results indicate that the proposed methods greatly improve the accuracy of queue size estimation as compared with the original SZM queue size estimation.

Influence of commutating reactance on the design of DC power supply converters

DC railway systems have now crystallised into the three major categories of 750V, 1500V and 3000V, the latter being applied to main-line systems and the first two mainly to urban masstransit or light-rail systems. This article reviews the significance of choice of transformer commutating reactance and highlights its importance in the design of DC substation convertors

Structure and creep in magnesia refractories

High-temperature creep of magnesia materials after the attainment of a certain critical deformation value is accompanied by the development of microscopic cracks. With the development of deformation there occurs a merging of the cracks into a mainline system and macroscopic destruction of the specimen close to brittle.

Digitalisation of palmar pattern configurations. Practicability in the anthropologic-heredobiological expert opinion (author's transl)

A half-automatic technique for extracting characteristics from handprints is presented. Characteristics of the mainline system are defined from the co-ordinate aggregates. The practicability of the method in the anthropologic-heredobiological expert opinion is discussed.

Transportation: Year of travail: Although some projects were halted or delayed, new urban and mainline systems are proceeding

The effect of adverse economic conditions on all forms of transportation is briefly discussed, and the observation is made that although some projects were halted or delayed, new urban and mainline systems are proceeding. Urban mass transit is considered to have been crippled even though transit technology has progressed. Automatic train operating systems in Montreal and Italy are described. The control systems also consist of an automatic train protection subsystem and an automatic train supervision subsystem. A West German Train-guidance System for a rapid transit network is also described. Another example of progress is the supertram concept (consisting of a 2-unit anticulated vehicle carried on 3 bogies) of the lightweight rapid-transit system of Newcastle, England. Two minisized electric cars marketed in the U.S. are outlined, and comment is made on the return of the trolley car.

L’évolution du réseau ferroviaire chinois et le nouvel équilibre régional

After an initial section describing the pre-1949 railway system in China, the author describes developments since that date. This is done in three stages, dealing successively with the creation of new international links and new main line systems, with developments of regional and interregional importance , and with the beginnings that have been made in the construction of lines to meet the needs of local areas. The author concludes that the developments that he described need to be assessed as a part of a coherent policy of regional development, and suggests that they emphasise the need to study the economic growth of China in regional terms.

Design of Catenary System for Cleveland Union Terminal

The article presents a brief description of the new electrification at Cleveland, Ohio, and the methods used in designing the overhead catenary system. The tangent chord compound catenary is used, the system being quite heavy. The main line construction weighs 3.855 and the yard construction 2.321 lb. per ft. dead load. The main line system is composed of a main messenger, an auxiliary messenger, and two contact wires hanging side by side. The yard system has a main messenger, and two contact wires, one above the other. The parabola formulas were used for the calculations, and where feasible, were made up in the form of charts, illustrations of which appear in the text.