Preface

Railways are unique among transport systems in that they use and maintain a wide range of technologies, some of which date back to the nineteenth century. In road and air travel enthusiasts maintain 'heritage assets' for people to enjoy recreationally, but in rail, particularly with respect to infrastructure, assets are very long lived (some are more than 100 years old) and continue to deliver public services. This applies not only to civil infrastructure such as bridges and track formations but also to other more technically complex assets. For example, in train control (signaling), every technology developed over the years, from mechanical interlockings based on rods and wires and electromechanical relays to computer-based systems and now even AI, remains in service somewhere. This requires the maintenance of a wide range of competences and supporting equipment, but it also offers many opportunities to apply new techniques and technologies to improve the efficiency of the maintenance and operation of such heritage systems. This book contains several examples of such innovations.

Railways are largely operated and delivered nationally, but railway equipment supply is increasingly global and dominated by a small number of big players. At the national level, requirements differ considerably, but all railways face challenges of performance, cost, and sustainability. In big cities like Hong Kong, Singapore, Beijing, Taipei, London, Paris, and others, the dominant concern is availability. Metros, in particular, have become an essential part of the way such big cities function, and the breakdown of even one line rapidly becomes a major problem leading to significant disruption. Such railways find it beneficial to invest in significant system redundancy and preventive maintenance measures to avoid or minimize failures. For rolling stock, onboard monitoring with continuous connectivity to a maintenance facility is now offered by all the major manufacturers, and increasingly, modern communications and sensors allow similar measures on infrastructure, particularly on Metros, given their small geographic scale and the needs described.

For rural passenger and freight railways, and for most railways in developing countries, the primary driver is cost. Rural railways in developed countries virtually never cover their infrastructure costs, and freight is always in tight competition with other modes in terms of cost per ton-mile/tonne-km. Improved monitoring and shifting maintenance from 'fix on fail' to 'predict and prevent' is a key strategy. The age of infrastructure is an important factor, with many of these railways more than 100 years old having structural issues due to corrosion or other aging effects. Climate change is also a consideration, with increased dry-wet cycles leading to issues such as embankments and bridge abutments moving, coupled with increased flood risk and degradation and failures driven by extremes of temperatures, humidity, and other climate conditions. As such, improved monitoring is necessary not only to control costs but also for safety reasons. Traditional monitoring using patrol inspections either on foot or using dedicated rail vehicles is expensive to implement and maintain.

Higher-density, long-distance passenger and commuter railways sit somewhere 'in the middle' and all these factors apply to some extent, as does a requirement for passenger comfort for long journeys.

Despite the maintenance issues mentioned, climate change also presents significant opportunities for rail transport. The key impact of transportation on the climate is driven by burning fossil fuels that largely produce CO2 as a greenhouse gas. On a comparative basis, rail occupies an advantageous position compared with other transportation modes in terms of carbon footprint. At the top of the scale is aviation; both domestic and long-haul flights contribute around 2% of the total anthropomorphic emissions of greenhouse gases. This is the current forecast, and with the improved greening of other sectors of the economy, the aviation industry's share is likely to increase.

In 1943, Thomas Watson the president of IBM, famously said that he thought that there was a world market for around five personal computers. Today, most of us carry a smartphone, which is a handheld computer with more power than Mr. Watson could have dreamed of. In 2021, around 15 billion smartphones were estimated to be in service.

The development and mass manufacture of such devices has made available compact, high-power microcomputers, high-quality voice and data communication, and very small sensors for (c.f.) acceleration, temperature, luminous intensity, sound (microphones and speakers), and, critically, Global Positioning Systems, all at very affordable costs.

These technologies have enabled distributed data acquisition at an affordable cost using either equipment on service trains or equipment distributed across the infrastructure. Low-cost and high-power signal processing allows for converting data gathered into useful information, including predicting maintenance needs in a way that allows prevention without wasting effort and money on 'planned maintenance' that is not needed.

This book includes many examples of advanced innovations and emerging techniques.

We think it is clear that 'predict and prevent' technologies will develop further. The increasing availability and power of autonomous and intelligent systems will further enhance the ability to extract useful information from data that at a simple level looks incoherent.

We extend our sincere appreciation to Publishing Process Managers Dajana Jusic and Elena Vracaric Managers at IntechOpen for their guidance and support in the preparation of this volume.

> **Ali G. Hessami** Director of R&D and Innovation, Vega Systems, UK

> > **Roderick Muttram** Fourth Insight, UK

Section 1 Infrastructure
