01.05.12
Why are UAS not being more widely used for rail network inspections?
Source: Rail Technology Magazine Apr/May 2012
Managing & Technical Director of VTOL Technologies, Ashley Bryant, a chartered engineer, chartered IT professional and member of the IMechE, reports on the new and rising Unmanned Aerial Systems and their value in the rail industry
The UK rail network covers over 20,000 miles of track, 40,000 bridges and tunnels as well as 2,500 railway stations. Network Rail owns this infrastructure, all of which requires regular inspection, including the rails, tracks and associated trackside structures, overhead power distribution, signals, tunnels, bridges, level crossings and even stations.
Regular inspection of this rail infrastructure is essential for safe and effective railway operation. The results of such inspections are typically used to prioritise short-term maintenance intervention and to plan longer term maintenance programmes. Increasingly, technology-based inspection solutions are being developed that provide accurate information on the condition of the infrastructure to support the development of cost-effective asset management. These technologies also have the potential to improve the safety of the public and railway personnel and to reduce inspection costs.
These monitoring systems, tuned to suit the operating conditions and constraints, may be mounted on specialised inspection vehicles or be hosted by vehicles operating in revenue service. Comprehensive backoffice software applications are then used to analyse, report and archive the data captured by the monitoring systems.
With such an extensive, long-distance UK rail network that winds its way through such varied geographies from urban centres, coastal routes through to windswept countryside, is there not a role to play for new and emerging technologies to augment current inspection services from the air?
Unmanned Aerial Systems (UAS) are an emerging technology that have seen widespread use in theatres of war in recent years, particularly in Iraq and now in Afghanistan. Military success, deploying such technology for Intelligence, Surveillance, Target Acquisition, and Reconnaissance (ISTAR) purposes has sparked the imagination of the commercial business sector, creating much food for thought as to where and how UAS can be successfully deployed for dull, dirty and potentially dangerous tasks to reduce risk, reduce cost and improve productivity.
As with any emerging technology, the challenge is very much centred on successful implementation and arguably the greatest stumbling block for commercial use of UAS today is in securing appropriate approvals for clearly defined operational tasks from national government organisations that control both airspace and airwaves, especially when the regulations are a moving target and by their very nature, often lag behind technological developments and advancements.
The most popular lightweight low-altitude UAS platform today is the ‘quadrocopter’, which looks rather like a square cross with a helicopter style rotor at the end of each arm, hence the term ‘quadrocopter’. Quadrocopter technology has a number of advantages; it is lightweight, has VTOL (the ability to take off and land vertically) and is highly manoeuvrable. However, its endurance is limited because it has no natural lift, unlike a ‘static wing’, and its top speed is again limited because it has no natural aerodynamic lift and its rotors do not vector, but are fixed in the vertical position.
The other significant constraint, particularly when involved in any ‘networkbased’ inspection business such as railway infrastructure, power-line transmission assets or even offshore wind farm inspection work is deployment Beyond Visual Line Of Sight (BVLOS), which requires not only far more stringent safety requirements than for systems deployed Within Visual Line Of Sight (WVLOS), but additional avionic systems. Crucially, the UK regulations for flying BVLOS require avionics for collision avoidance which adds to the overall weight, reduces endurance and can also demand a change in task operation.
According to recent reports, Network Rail is starting the process of evaluating UAS technology for rail network asset inspection work. Such systems are likely to gravitate around the use of lightweight, very lowaltitude systems, typically carrying a high-definition colour camera with an associated infra-red camera known as the working payload. The advantages are clear; improved safety by reducing the need for people to work at height, reduced costs with the ability to inspect overhead powerline catenary assets whilst they are still ‘live’, without shutdowns and significant time savings, since the right type of UAS can be airborne and operational, literally within seconds.
The key step for rail network inspections is going to be operating BVLOS systems, which will require either an augmentation of capabilities from currently available WVLOS VTOL UAS platforms, or ‘taking the plunge’ and investing in the development of specifically designed BVLOS systems, because current WVLOS UAS platforms have not been specifically designed for BVLOS operations and lack crucial flight capabilities essential for such operations including significantly extended endurance and a fast return speed once the scheduled length of the rail network has been inspected.
The key questions that need to be addressed, for this technology to truly ‘take-off’ for aerial inspection work, are:
1. Can the use of UAS technology, in support of inspection operations on the UK railway network (including support of anti coppertheft operations), be successfully exploited for commercial advantage, addressing strategic business goals?
2. If so, what would the benefits be and what would such operations look like?
3. Could such exploitation be financially justified?
4. Is it possible to get appropriate Civil Aviation Authority (CAA) certification for safe operations throughout the UK railway sector?
5. And, only if the answer is yes to all of the above questions, what type of UAS solution would best suite UK railway surveillance and inspection operation requirements?
The most critical element will be fully defining the operational task from an end-user perspective, without initially considering current UAS platform or payload limitations. Once the task is clearly defined, then alternative payloads can be evaluated to match task delivery needs. Only then should the UAS airframe be selected to match the manoeuvrability, range, endurance and either WVLOS or BVLOS requirements.
The final stage in putting together the right operational solution is to evaluate the ground station and the specialist command & control functions, essential to successfully manoeuvring the UAS airframe and payload so that it can do its job effectively.
Over time, specialist command & control sequences and manoeuvres will very likely be developed to optimise execution of inspection tasks, all controlled from the ground station, using the ground station’s knowledge of the network assets to be inspected.
The last and most important step in the process is achieving CAA operational task/flight approval(s). The previous steps outlined above are essential for the development of the operational safety case that needs to be presented to the CAA, particularly for BVLOS operations. It may not be that well-known, but the UK leads the world in UAS test facilities and has a comprehensive and fully operational UAS test facility at Parc Aberporth in West Wales for proving the safety case and securing CAA approval(s).
Who knows how far this technology could be developed to improve safety and security of the rail network. The right type of VTOL UAS platform has the potential to be launched directly from trains travelling at over 80mph.
Although the development of this type of capability is some way off, such a system might be a valuable deterrent in providing an immediate surveillance response to catch those members of society who drop objects from bridges onto oncoming trains, causing not only damage to rolling stock, but also with the potential for loss of life as the photograph illustrates.
The future will see industry-specific specialist UAS platforms being developed. One exciting VTOL UAS platform currently under development is a VTOL Flying Wing that has the promise to significantly extend range, endurance and payload, all essential elements for achieving BVLOS approval for rail-network inspections as well as the potential to be launched automatically from fast-moving trains.
VTOL Technologies is a company providing UAS exploitation consultancy for businesses seeking to optimise the use of UAS and requiring support in securing CAA approvals for both WVLOS and BVLOS systems over both land and/or sea.
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