Zero Power, Large Area Rail Track Monitoring

The delivery of efficient and safe railway operations is considered of vital importance to the UK's economy and society. Currently the UK has 4,000 trains using 20,000 miles of track and 1.7 billion passenger journeys annually. 400,000 tonnes of freight each day are transported over rail and these numbers are forecast to increase. Delays, unplanned disruption or reduction in availability due to unplanned maintenance have serious repercussions on the mobility of passengers and freight. Railway track and rolling stock interact with each other, forming a complex dynamic system which leads to structural degradation of railway assets with time. It is therefore of utmost importance that events and mechanisms causing damage initiation and propagation in the railway track are detected in real time and evaluated for translating events and mechanisms into predictive and preventive maintenance plans. In 2017 the UK Government set up a strategic vision for rail, for the short- and long-term, to address the need for: 'a more reliable, efficient, modern railway in 2019-24; a step change for railway (2024-2029); a world-class railway beyond 2030'.

One of the grand challenges for the industry has been inspecting the track and quantifying its damage on such a vast scale. Observations need to be autonomous and sustainable, defects detected at an early stage, and maintenance work optimised, to reduce the risk of failure and to increase availability, safety and reliability. One powerful means of inspection is to develop permanently installed, self-powered sensors, e.g. accelerometers, strain gauges and acoustic emission (AE) sensors on the tracks, which measure track deflection, vibration, and wheel-rail track interactions, and are wirelessly connected to an operation and management centre with automated data processing capability. The development of such self-powered, wide area rail track monitoring will lead to radical change in the management of railway infrastructure, and considerably enhanced efficiencies, economies and adaptability, improving the competitiveness of our whole railway system. Greater connectivity and sensor coverage along tracks which require no mains power or batteries for energy supply, eliminating the costs for cabling and battery replacement, and minimum gateway installations, are critical for the success of industry adoptions.

The principal novelty of this research is to develop cross-cutting, bespoke, deployable technologies and an associated demonstrator of a zero power, large geographical area rail track monitoring system. Current technological capabilities do not permit such scaling-up for high connectivity and wide area coverage, e.g. the entire UK rail network. This project will fill this technological gap by developing an integrated whole-system approach from energy harvesting (EH), power management, low power wide area networks (LPWAN), remote condition monitoring to data explanation. In the future, it will enable Network Rail to implement efficient predictive and preventive maintenance planning, thereby improving the reliability and availability of the railway, which in turn promises to promote UK economic growth through increased mobility. The project's research outputs are expected to transform rail track monitoring capability in the 21st century, in the UK and internationally.

This research will build upon the University of Exeter's track record of EH powered wireless sensor systems, and high performance computing and networking, and the University of Birmingham's expertise in rail track condition monitoring. The research will be supported by Network Rail and other industrial partners to ensure its impact readiness. The project partners are: three Divisions from Network Rail of Track Renewals (Birmingham) and Infrastructure Projects and Telecom (Milton Keynes), Quattro (London) and Swiss Approval International Group of Companies (Lanarkshire).

The major commercial beneficiaries include: industrial Internet of Things, emerging EH technology sectors, remote condition monitoring, ICT-energy, and predictive and preventive engineering services. In terms of end-users and stakeholders, the key beneficiaries include: UK Government, Network Rail, Rail Supply Group, Rail Delivery Group, Planning Oversight Group, and National Task Force. In terms of technology developers, the key beneficiaries include: product designers/engineers, researchers and UG/PG students interested in EH powered wireless sensor networks. On a wider level, society, the economy and the general public stand to gain considerably. If funded, this research will considerably improve Network Rail's ability to monitor and maintain the UK's rail network. It will transform the current approach of manual, time-consuming, limited area monitoring which often results in unplanned, expensive and disruptive maintenance, into an autonomous real-time, large area coverage monitoring, with a planned and preventive approach. The impact that this research will have is described below.

Knowledge that will support further development of the research community:
1. Bespoke energy transducers for high power and highly reliable rail track EH
2. Bespoke low power wide area networks (LPWAN) for scalability and coverage for a large number of sensor networks powered by EH
3. Bespoke power management and energy storage methods for rail track monitoring
4. A pioneering and bespoke deployable technology demonstrator for zero power, large geographic area rail track condition monitoring

Economic & industry growth: Once implemented into the rail market, the proposed technology will form an important part of rail track condition monitoring systems. These systems have the potential to realise elements of the Rail Technical Strategy Capability Delivery Plan, including contributions towards £458m annual benefits by delivering "minimum disruption to train services", £725m annual benefits by leveraging "more value from data", and £228m annual benefits by achieving "optimum energy use" (Rail Delivery Group and Rail Supply Group (2017): Rail Technical Strategy Capability Delivery Plan). Were our technology to become available, it would transform the current maintenance system from 'unplanned and disruptive' to 'planned and preventive'. The technology would generate a considerable amount of new and important data supporting growth of the UK's data engineering service industry. The technology would also use ambient vibration energy to eliminate the need for mains power or batteries, and the associated cabling and battery costs.

Societal improvements: The increased availability, capacity, safety, and reliability of the railway's public services, will better support passenger mobility and the transportation of goods. Any maintenance works will be planned and addressed in a timely manner, avoiding unplanned disruptions and last-minute track closures. Network Rail - and potentially their international peers in the future - will have the ability to monitor the condition of the rail track in an autonomous and sustainable manner, detecting and evaluating hundreds of thousands of miles of track in real-time. Hence they will be better placed to accommodate and promote economic and industry growth.

People: In addition to the academic training programmes delivered to PDRA/PhD posts at UoE and UoB, these researchers will develop world-leading skills in EH powered wireless sensor system design, prototyping and testing. They will gain understandings of (i) the industrial requirements for rail track monitoring and how requirements and specifications translate into and influence subsystem and system designs, and (ii) the stringent requirements placed on system design. The other crucial benefit emerging from our outreach will be to stimulate the interest of young scientists and engineers through our attendance at the British Science Week.