Preface

Railways are the backbone of any transportation system and essential elements for environmental sustainability and the social equity of transport.

Currently, railway engineering is facing different and complex challenges due to the growing demand for travel, the new technologies, and new mobility paradigms that are significantly changing the "railway world."

Today, it is more important than ever to better understand revolutions in technology to develop and test effective and efficient approaches to address and integrate technologies and infrastructures within the planning, design and management of transportation systems.

All these issues require a clear knowledge of the pros and cons of the traditional transportation planning methodologies, existing technologies, and robust theoretical frameworks and should be supported by reliable and transferable validation tests.

This book examines railway systems from different perspectives of planning, management, performance analysis, and sustainable solutions (e.g., the use of hydrogen as fuel).

The book is organized into five chapters.

Chapter 1 proposes a methodology for selecting a transport strategy for railway passenger transport development. Specifically, the chapter applies Political, Economic, Social, Technological, Legal, and Environmental (PESTLE) analysis and Strengths, Weaknesses, Opportunities, Threats (SWOT) analysis integrated with multiplecriteria decision-making (MCDM). The proposed methodology is composed of five stages. The first stage formulates the alternatives of the policies for railway managers. The criteria in each PESTLE group are defined in the second stage (twentyfour criteria are studied). In the third stage, the SIMUS method based on linear programming is applied to rank the alternatives and assess the criteria in PESTLE groups. In the fourth stage, different multi-criteria approaches (distance-based, utility-based, and outranking methods) are implemented to get a final ranking. In the fifth stage, PESTLE analysis is combined with SWOT analysis for strategic planning. In particular, the chapter presents the integration of PESTLE with technical, economic, technological, and environmental (TETE) analysis. Finally, the chapter presents a case study on the Bulgarian railway network and evaluates and compares three strategies of railway transport development.

Chapter 2 describes the cognitive biases that may be found in the railway transport planning and management domain. Cognitive biases in the planning of railway projects lead to cost overruns and failure to achieve performance and fulfill safety objectives, as is noted in the economics, business management, and risk management literature. Unbiased decision-making is a key aim of systems engineering, encouraging careful consideration of stakeholder needs, design alternatives, and

programmatic constraints and risks. Nevertheless, systems engineering practices dealing with railway transport planning and management fields do not pay attention to the human and organisational factors at the initial stages of planning. Results show that the Guide to Railway Investment Process (GRIP) (2019) has no provision for incorporating measures to address deficiencies raised by accident or safety analysis reports because the RSSB Taking Safe Decisions Framework does not include all the heuristics and the biases that usually occur and that may be used for taking decisions.

Chapter 3 proposes an analysis of the methods used in diagnostics of railway lines. Complex diagnostics of railway lines involves techniques based on discrete and continual data acquisition. While discrete measurements belong to conventional methods, the modern continual ones use automated robotized instruments with continuous recording. Even if observations have become more time-efficient, the processing epoch has become longer to evaluate a large amount of data. Railway line diagnostics are realized by methods to determine relative track parameters such as track gauge, elevation, and track gradients. Absolute, geodetic techniques determine directional and height ratios of the track, defined in a global coordinate and height system.

Chapter 4 investigates new methods for monitoring the dynamic processes of rolling stock/rail interaction and shows a new technical solution for measuring the wheel/rail interaction forces on a significant part of the sleeper. The adoption of the Finite Element Method (FEM) confirms the ability of piecewise continuous recording of vertical and lateral forces from the wheel/rail interaction by measuring the stresses in two sections of the rail. It also determines the optimum location of strain gauges and the effective length of the measuring zone. Additionally, the experiment confirms the effectiveness of the method to determine the vertical and lateral wheel/rail interaction forces and, at the same time, increases the statistical reliability of the data, improves the measurement accuracy, and reduces the time and cost as compared with current testing methods. Finally, the developed method is recommended to determine the wheel/rail interaction forces and identify defects on the wheels when diagnosing rolling stock on operational and travel regimes.

Chapter 5 focuses on hydrogen as a rail mass transit fuel. It provides an overview of methods to generate hydrogen, power drives (fuel cells and hydrogen internal combustion engine), location of the hydrogen generators and H2 transmission to users, safety and codes, and hydrogen-fueled trains. It also gives some examples of possible decarbonized trains in Australia, the United Kingdom, the United States, and Saudi Arabia together with an emission and fuel costs comparison.

> **Stefano de Luca, Roberta Di Pace and Chiara Fiori** Department of Civil Engineering, University of Salerno, Fisciano, Italy

## **Chapter 1**
