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Can Scotland lead the way in high-speed trains?…


Profile: XiTRACK

Core business:    Railway innovation
Key innovations:  XiTRACK (geosynthetic reinforcement for railway tracks) and DART3D (ground vibration simulation software for railways)
Location:            School of the Built Environment, Heriot-Watt University
Major contracts: Network Rail, Balfour Beatty Rail

Can Scotland lead the way in high-speed trains?

If Professor Peter Woodward got his way, construction of the UK's next high-speed rail network would start in Scotland – tomorrow. “If we want the northern economic base to grow,” he says, “we should build high-speed lines in the north first, not the other way round.” And just for good measure, adds Woodward, the trains would be powered by renewable energy, generated north of the border.  

Woodward, who is Professor of Railway Geotechnical Engineering in the School of the Built Environment at Heriot-Watt University, is not just an evangelist for high-speed trains, but also wants the UK to reclaim its traditional role as a leader in rail innovation – a role which he believes has been eroded by an increasingly risk-averse industry, as well as by the effects of lower-cost competition from overseas countries since Victorian times, when the UK ruled the world in rail technology.

High-speed trains will dominate the future of the railways, says Woodward, and by the time HS2 (High Speed 2) is completed in 2026, other countries will be steaming ahead. China, for example, plans to build 20,000km of high-speed track by 2020, with trains achieving maximum speeds of over 310mph, compared to 250mph on the London–Birmingham route – a distance of only 140 miles. More than 30 US states are currently investigating new high-speed railways, and Woodward thinks that Scotland should be taking the initiative, not just for economic but also for environmental reasons.

“Industry and academia need to work closely together to generate rapid progress in innovation and product development,” Woodward explains. “Now is the age of the train!”

Woodward laments the UK’s reluctance to adopt new solutions for railways, but says that innovation is still taking place here, despite this. To drive more innovation, Heriot-Watt is setting up the UK’s biggest testing rig for railway technologies, and Woodward hopes that this will convince industry to set up a national testing centre, to stimulate development and also boost exports. 

“We can’t compete with countries like China when it comes to manufacturing widgets,” says Woodward, “but the UK has got the ability to develop innovations. Our problem is how to commercialise these – for example, we developed the first tilting trains but Italy now exports its Pendelinos to us.” 

The XiTRACK story

Woodward's interest in railways developed in the late 1990s at Heriot-Watt, where he became a lecturer in 1994 after gaining his PhD in numerical geotechnics from the University of Manchester. In his early career, he focused on earthquake engineering, modelling ground waves and their effects on civil engineering structures – experience which he continues to use today in developing numerical modelling software for railways.

Initially, Woodward started looking at ground vibration waves and how they affect the ballast on railway tracks. Ballast is good at supporting the rails and helping drainage, but it also tends to ‘densify’ and can break down, due to vibration from trains running over the rails, and eventually this affects the geometry of the track – especially at switches and crossings – and requires regular maintenance. Some sections of track need checking once a year and others as often as every ten days. Anything which would prevent this would not only save money but also be safer. 

In 1999, one of Woodward’s colleagues was involved in the replacement of the cobbles in Edinburgh’s historic Royal Mile, using polyurethane to help reduce the wear and tear on the new cobbles, filling in the space around the cobbles much the same as using grout for tiles. And this got Woodward thinking – maybe a similar polymer could be used for the ballast on railways.  Woodward then started discussions with the polymer supplier, a company called Hyperlast, and started to develop a special solution for railways. 

XiTRACK was first trialled at Bletchley on the west-coast line in early 2000 – points which used to need maintenance every three months. The new solution was installed while the trains were still running, using a pneumatic pump to apply the polymer between the sleepers. And the trial was so successful that the points did not need any further maintenance until they were decommissioned in 2011.

One of the special properties of the innovative geocomposite solution is that it cures (or sets) at different rates, depending on the formula – e.g. it is poured into the ballast (like cream over strawberries) and when it reaches a particular design depth (of between 100mm and 600mm), it stops running further. This means engineers can control application to meet individual requirements. Other formulas have also been developed to be effective in temperatures as low as minus 40°C.  

According to Woodward, one of XiTRACK’s major advantages is that it can be used to fix a problem overnight without interrupting the schedule.  Concrete slabs are also low-maintenance options, but are more expensive to build and replace, and their longevity is still being debated. “XiTRACK offers the best of both worlds,” adds Woodward. 

After the initial trial, Heriot-Watt University then spun out a company called 2Ei to develop and market the product, and in 2001 Woodward founded XiTRACK as a 50:50 joint venture with Hyperlast Ltd (now the Dow Chemical Company).  The company then won a contract from Railtrack to reinforce the track at 14 bridges nationwide, and Woodward started spending 25 per cent of his time working at XiTRACK – an arrangement which at that time was highly unusual for academics. 

The business started gaining momentum when XiTRACK formed a partnership with Balfour Beatty Rail and started a series of trials up to 2005, using new electrical pumps to install XiTRACK at the contractor’s ‘worst sites’ – bridges, switches and crossings where stabilisation was needed the most.  In 2005, XiTRACK was officially certificated by Network Rail (which took over from Railtrack in 2002) and the company was highly commended in that year’s ‘Innovation of the Year’ category at the 2005 National Rail Awards. 

“There are two main arguments for XiTRACK,” says Woodward. “First, it reduces the maintenance costs.  And second, it lowers the risks. The technology has the capacity to virtually eliminate the need for ballast maintenance, and Balfour Beatty Rail is now promoting the concept of ‘tamperless’ switches and crossings.” 

XiTRACK has been used in Italy and is also due to be trialled at 25 sites in Germany and Hong Kong. Woodward comments: “Countries outside the UK are more ready to use innovative solutions. Some people in the UK seem to think that if the Victorians didn't use the technology, we shouldn't use it – but if the Victorians had XiTRACK then, they would have used it!”

Modelling software

In the process of developing XiTRACK, Woodward developed new modelling software to “model every aspect of the rail environment, including the effect of vibration on buildings and the people inside them.” 

One phenomenon which this reveals is something called “critical velocity.” Every type of groundsoil has a ‘natural velocity’, with different densities absorbing the ground waves at different velocities.

The new software, called DART3D (Dynamic Analysis of Railway Track 3D), simulates these effects and allows the engineers to work out howto mitigate vibration – whether this means laying concrete rafts, improving the ballast using geosynthetics such as XiTRACK, or even rerouting the track. “Different types of soil may react at different speeds,” says Woodward, “but the faster you go, the more it's a factor.”

Woodward and his academic colleagues, including Professor Michael Forde of the University of Edinburgh, have successfully applied for EPSRC funding for the simulation software and are also in discussion with researchers in China to use it for next-generation ultra-speed train modelling – travelling at over 250mph. “The Chinese are the new Victorians,” says Woodward. “They just get on and do things.”

Over the last few years, Woodward has done everything from shovelling ballast to chairing boardroom meetings, in his quest for railway innovation. This year, he will give the keynote speech at a major conference in China, where his ideas could be critical in planning for the new high-speed network. His talk is entitled: The application of polyurethane geocomposites to help maintain track geometry for ballasted high-speed railway tracks. He is also giving talks this year on high-speed tracks in Japan, Australia and Spain (the latter is a keynote on ultra-speed). Will the same ideas resonate in Scotland?


The need for speed

Train speeds have increased in a number of stages since the dawn of the steam age in 1803. “It took 100 years to go from 5mph to 128mph,” says Professor Peter Woodward, “another 76 years to reach 198mph and only a further 28 years to reach 357mph.”

In the quest for speed, a wide range of technologies has come and gone, including Hovertrains and Aerotrains(jet-propelled), while MagLevs (Magnetic Levitation trains), first developed in the UK in the 1940s, achieved the rail speed record of 361mph in Japan in 2003. This compares to a Boeing 737 which flies at a speed of about 490mph. 

The UK’s first high-speed railway was the Channel Tunnel Rail Link which goes at 186mph, while the planned HS2 train is expected to run at a top speed of 250mph.



"XiTRACK". Science Scotland (Issue Twelve)
Printed from on 05/07/20 10:37:30 PM

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