A smarter, faster way to manage and reduce risks on rail networks

October 6, 2020

Posted by: Anasia D'mello

The UK suffered a spate of high profile tragedies on its rail network in the late ’90s and early 2000s. Fortunately, since then rail accidents have been mercifully absent from the news – indeed the UK has had over a decade of zero deaths on its railways, says Stuart Large, product line director, Fotech.

However, a serious derailment caused by a landslide in Aberdeenshire, Scotland on 12th August 2020 provided a major wake-up call. Indeed, as network rail chief executive, Andrew Haines said, the Stonehaven tragedy was “a stark reminder that we must never take running a safe railway for granted”.

Weather warning

Since the incident Network Rail has launched two independent task forces to improve its understanding and response to severe weather, and better manage its earthworks portfolio. However, the incident is also a timely reminder of the huge monitoring and maintenance challenge that rail networks represent.

Railways cover huge distances, often in remote locations, and network managers need as many tools as possible to not only understand the live status of the network, but to respond rapidly to incidents when they occur.

Of course, technology already plays a huge role in this management – but the question raised by the recent accident in Scotland is whether there is more that can be done. If we are to minimise risks, enhance safety and avert disasters then we must further enhance the visibility of threats to rail lines and accelerate response times.

Understanding the scale of the challenge

In an interview last year, Robert Cook, head of Strategic Projects at the Office for Rail and Road (ORR) in the UK, emphasised just how challenging monitoring and maintaining the health of rail infrastructure is. Cook highlighted how repair works and upgrades to rail infrastructure can be “monolithic tasks that can require years of work across miles of ground and involve numerous different companies and shareholders”.

In fact, Cook stated clearly that “asset sustainability has been a really big risk” for rail infrastructure in the UK and that “the long-term cost of keeping it in a steady state was going up”. Indeed, recent data from the ORR showed that payments from Network Rail – the owner and manager of the UK’s rail infrastructure – to train operators for planned and unplanned disruption rose by £52 million (€57.3 million) in 2017/18, totalling £439 million (€484 million) for the year. And it’s not just the UK; planned and unplanned maintenance is a huge cost for rail operators around the world.

The scale of the challenge, however, does not make maintenance, and upgrade work – or safety enhancements – any less crucial. One area of focus for improving rail safety is using technology to enhance remote condition monitoring (RCM) on rail networks.

‘Predict and prevent’

For example, Network Rail’s infrastructure maintenance strategy is focused on using RCM to enable a predict and prevent approach and to reduce the costs and safety risks associated with scheduled maintenance regimes. Part of the challenge of implementing this strategy are the limitations of many of the technology systems currently employed on rail networks.

General systems such as closed circuit TV (CCTV) cameras are used around key facilities and infrastructure, and some specialised devices exist to monitor activity on the rail network itself. However, these devices are limited operationally – generally offering monitoring at a single fixed location.

What train operators really require, is a nationally scalable sensor platform – not only to enhance visibility across the entire network, but also to support more robust artificial intelligence (AI) and predictive analytics.

Rethinking rail network monitoring

Rather than looking to deploy additional technology infrastructure to solve this challenge – adding to the cost and disruption Robert Cook highlighted – rail operators can instead look at alternative solutions. For example, existing ‘dark’ track-side fibre optic cables can potentially provide the basis for a network-wide monitoring system.

The key would be the addition of Distributed Acoustic Sensor (DAS) technology. DAS upgrades a traditional fibre optic cable to effectively convert it into thousands of vibration sensors, akin to placing an army of microphones alongside the rail. A laser shoots thousands of pulses of light down a cable each second. A minor proportion of this light is reflected, and any disturbances in the light pattern will be picked up by the sensor. Each kind of disturbance has its own signature and advanced algorithms in the technology can tell an operator what happened, exactly where it happened and when it happened.

Stuart Large

By using the fibre alongside a rail line, DAS can provide full continuous monitoring of its entire length – at only incremental cost and with virtually zero disruption as it essentially ‘plugs in’ to the fibre which is already in place.

DAS-enabled fibre gives operators access to a huge range of monitoring capabilities. Operationally DAS can help operators track trains along complete railway sections in real-time – providing reliable information on train speed for encounter prevention and alerts on trains that are operating outside expected parameters.

DAS can also identify a range of failures to support more strategic, smaller, ongoing, and more proactive maintenance, rather than only knowing there is a problem when something major fails. This includes pinpointing flat wheels and rail defects such as loose sleepers, loose track ties, rail squat and rail break. Austrian rail operator OBB has even demonstrated how it has used DAS to aid the detection and location of flashover events in overhead catenary cables.

Austrian rail operator OBB has even demonstrated how it has used DAS to aid the detection and location of flashover events and finally, when it comes to safety and security, rail-side DAS can be used to detect intruding personnel, identify landslides and rockfall events and alert on-route trains to prevent incidents before they even occur.

Making zero incidents a reality

Live trials are underway in a number of countries – including the UK – for some priority applications and a new industry body (FOS4R – Fibre Optic Sensing for Rail) created by operators will help accelerate the adoption of fibre-based monitoring.

Ultimately though, this isn’t about the technology. This is about delivering better, safer railways, more efficiently and with less passenger disruption – to ensure that incidents like the recent tragedy in Scotland become ever rarer the world over.

The author is Stuart Large, product line director, Fotech.

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