Restructuring the Greek Railways: Current Progress and Evaluation of Alternative Schemes

Abstract

This paper presents the rationale, the method, and the alternative choices in the process of restructuring the Hellenic Railways Organisation (OSE). The most likely alternative structures regarding ownership and management issues of the new entities that will inherit the old OSE organization, and discusses the strategic implications of these alternatives are discussed. A critical view of the process of Greek railway reform and the evaluation results of the alternative organizational structures for the new situation are presented. It first presents the current experience in European Union and other countries of Europe, and the relative position of the Greek railways vis‐à‐vis the most common practices. The most likely options for the new organizational structure are presented which will result from the application of the European Union Directives and the Greek Law 2671/98 for the reorganization of the Greek railways. Based on a more detailed presentation of expected income and expenditures (i.e. economic viability) of the alternatives, a structure and a roadmap to these reforms is recommended for a successful and, above all ‘implementable’, reform of the Greek railways under the current conditions. Finally, the process for change and restructuring is described in terms of the basic principles and procedures that should be followed, and in terms of the necessary steps and procedures for the transition from the current to the new situation.     

Do Public Transport Improvements Increase Agglomeration Economies? A Review of Literature and an Agenda for Research

Public transport improvements may increase economic productivity if they enable the growth and densification of cities, downtowns, or industrial clusters and thereby increase external agglomeration economies. It has been argued that the potential agglomeration benefits are large; if so, understanding them better would be useful in making funding decisions about public transport improvements. We reviewed theoretical and empirical literature on agglomeration as well as a small number of articles on transportation's role in agglomeration. The theoretical literature is useful in understanding possible avenues by which transportation improvements might affect agglomeration, although there is little discussion of public transport specifically. Relevant empirical studies tend to focus on metropolitan regions and use a generalized measure of transportation cost. But public transport impacts on agglomeration are likely to be different from road investment impacts. We identified several ways of conducting research building on this literature that would help evaluate the agglomeration impacts of public transport proposals: tracing the links between transport, agglomeration, and productivity; better motivating research using theories of agglomeration mechanisms; taking scale and redistribution into account; exploring the functional form of agglomeration economies; accounting for endogeneity in model structure; and considering development context.     

On the definition of traffic equilibrium

Three alternative definitions of traffic equilibrium are compared in terms of the mechanisms of route-choice inherent in them. These definitions are the usual Wardrop equilibrium and user-optimised ones and a new one. Conditions on the cost function are established under which the Wardrop definition is equivalent to each of the other two. Some circumstances are identified in which these conditions are satisfied. A detailed discussion is given of an example in which these conditions are not satisfied and the three definitions are not equivalent.     

What influences satisfaction and loyalty in public transport? A review of the literature

Public transport ridership retention is a challenge for many cities. To develop comprehensive strategies aimed at retaining riders, it is necessary to understand the aspects of public transport that influence users to become loyal to the system. This paper analyses relevant literature regarding the causes of satisfaction and loyalty in public transport. We find that the service factors most associated with satisfaction are on-board cleanliness and comfort, courteous and helpful behaviour from operators, safety, as well as punctuality and frequency of service. On the other hand, loyalty is associated with users’ perceptions of value-for-money, on-board safety and cleanliness, interactions with personnel and the image and commitment to public transport that users feels. Furthermore, the results elucidate that the concept of loyalty is best defined based on users’ intentions to continue using the service, their willingness to recommend it to others, their overall satisfaction, but also and most importantly, their image of and involvement with public transport. Public transport users who have a positive image of the agency and consider public transport an integral component of city life are more likely to demonstrate loyalty and act like ambassadors for public transport agencies.     

Isrss: Integrated side/rear safety system

As driver assistant systems (DAS) and active safety vehicles (ASV) with various functions become popular, it is not uncommon for multiple systems to be installed on a vehicle. If each function uses its own sensors and processing unit, it will make installation difficult and raise the cost of the vehicle. As a countermeasure, research integrating multiple functions into a single system has been pursued and is expected to make installation easier, decrease power consumption, and reduce vehicle pricing. This paper proposes a novel side/rear safety system using only one scanning laser radar, which is installed in the rear corner of the driver’s side. Our proposed system, ISRSS (integrated side/rear safety system), integrates and implements four system functions: BSD (blind spot detection), RCWS (rear collision warning system), semi-automatic perpendicular parking, and semi-automatic parallel parking. BSD and RCWS, which operate while the vehicle is running, share a common signal processing result. The target position designation for perpendicular parking and parallel parking situations is based on the same signal processing. Furthermore, as system functions during running and those during automatic parking operate in exclusive situations, they can share common sensors and processing units efficiently. BSD and RCWS system functions were proved with 13025 and 2319 frames, respectively. The target position designation for perpendicular and parallel parking situations was evaluated with 112 and 52 situations and shows a success rate of 98.2% and 92.3%, respectively.     

Compensation factor method for modeling springback of auto parts constructed with high-strength steel

To more accurately manufacture an auto-body workpiece, a predictive compensation factor method was used to predict the workpiece’s springback, and the factors influencing springback are introduced. Based on this method, a numerical simulation was produced to simulate the springback compensation after distortion of the workpiece. After analyzing the simulation results, a compensation method was introduced to reduce the springback influence on an actual workpiece. Here, we used a fortified B-pillar, which is a kind of longitudinal stand-frame workpiece, made with a high-strength steel material (TRIP700). The simulation results indicated that the proposed method is feasible and can be efficiently used for predicting the distortion of springback compensation of an auto-body workpiece.     

Performance of radial-type metal foam diesel particulate filters

An analytical study of the performance of a radial-type, metal foam diesel particulate filter is reported. A mathematical model for the filtration and regeneration of soot in a metal foam filter was developed. Nickel foam was selected for the filter medium due to its large specific area, high porosity, and high thermal resistance. For various metal foams, the filtration efficiency and the pressure drop through the filter were calculated, as was the deposition of soot. The results from the analytical model were compared with experimental data. In comparison with a conventional wall flow filter, the metal foam diesel particulate filter (DPF) is effective in utilizing the volume of material, due to the porous structures. As the size of the metal foam pores in the DPF increases from 580 μm to 800 μm, the filtration efficiency decreases from 90% to 50%, and the pressure drop decreases from 380 mbar to 20 mbar. The metal foam DPF with a large pore size is effective in utilizing the volume of material with a small pressure drop. The regeneration is completed within four minutes by the flow of hot exhaust gases under full load conditions.     

Optimization of bus rollover strength by consideration of the energy absorption ability

Buses are an integral part of the national transportation system of each country. A rollover event is one of the most important hazards that concerns the safety of the passengers and the crew in a bus. In the past, it was observed after the accident that the deforming superstructure seriously threatens the lives of the passengers. Thus, the stiffness of the bus frame is the first thing that needs to be considered. The unfortunate side of strengthening the bus superstructure is that it usually causes the bus weight to increase. This paper presents an efficient and robust analysis method with which to design the bus superstructure for a reduction in occupant injuries from rollover accidents while the weight of the strengthened bus is maintained at the same level. First, the absorbed energy of the bus frame and its components during a rollover were investigated by using a LS-DYNA numerical study. The highest energy absorption region, which is the side section of the bus frame, was found and focused on for the investigation of a means to re-distribute the energy-absorption ability of the side frame component. Then the thickness parameters that were obtained from the re-distribution of the energy-absorption ability were used in the analysis to optimize the design. Finally, a prototype of the bus with a reasonable thickness for the window pillars and the side wall bars, which was based on the optimized parameters, was verified to ensure it satisfied ECE R66. In this paper, an effective usage of materials and an efficient and robust analysis method were presented to design the bus superstructure. Although the optimization process for increasing the stiffness is simple, this study improves the upper displacement by 39.9% and the lower displacement by 49.3% (versus the bus survivor space) while maintaining the bus weight at the existing level.     

Parallel model based fault detection algorithm for electronic parking brake system

This paper describes a parallel model-based fault detection algorithm for an electronic parking brake (EPB) system, which consists of an electronic control unit with built-in current sensor and braking force sensor. For the EPB system to supply sufficient parking force to a vehicle, the parking force sensor is of utmost importance. If a fault occurs in this sensor, sufficient parking force may not be supplied, thereby seriously threatening the safety of the vehicle. Thus, a fault detection method is required for the parking force sensor of the EPB system to improve the safety of vehicles. For this purpose, a highly reliable fault detection method is needed to detect abnormal fault signals, which cannot be detected by the existing on-line sensor monitoring fault detection methods. This paper proposes a novel parallel model-based fault detection algorithm for the EPB system, which compares the physical sensor data with the mathematical model, the fuzzy model, and the neural network model at the same time. In order to reduce false alarms, the magnitude of thresholds and the operation counts are changed adaptively. When the proposed parallel model-based fault detection algorithm detects severe failures of the force sensor, it warns the driver in advance to prevent accidents due to the failures. The proposed algorithm is verified by hardware-in-theloop simulations in various situations.