Developing alarm and track signalling systems for the rail industry

How our researchers helped the nation鈥檚 railways make advances in safe signalling and alarm technology
Plymouth railway station
With more than 10,000 miles of track, and the responsibility for carrying 1.5 billion passengers and 拢870 million worth of freight annually, the railways of Great Britain are a key part of the national circulatory system. And like any system, the efficiency and reliability with which it can transport its lifeblood are integral to its success.
It鈥檚 a story worth celebrating therefore, that University researchers in the fields of psychology and mathematics, have helped the nation鈥檚 railways make some revolutionary advances in areas such as safe signalling and alarm technology.
鈥淭he system for detecting whether trains are on the track has been based upon a principle that is several hundred years old,鈥 said Professor Martin Tomlinson, Chair of Communication in the School of Computing and Mathematics. 鈥淓ach section of the track has two rails, and so with the steel wheels of the train, you can create a circuit. If a train is on the track, it forms a closed circuit which can be used to switch on a light or change a signal.鈥
In 2006 an opportunity arose for Martin and his team in the Centre for Security, Communications and Network Research to use their expertise in coding to help design a next-generation signalling system. Entering into a Knowledge Transfer Partnership with Bombardier Transportation UK, the team created a system of binary codes that could be 鈥榠njected鈥 into the track via a signalling box.
鈥淭he key to the work was using mathematical principles to create codes that could be up to 100 digits long, and which had a large enough distance between them to ensure the overall system was robust,鈥 Martin said.
The work became the basis of the EBI Track 400 product, which underwent an extremely rigorous testing process overseen by Associate Professor Mohammed Zaki Ahmed. Launched in 2008, EBI Track 400 was lauded by the Institution of Railway Signal Engineers as 鈥渁 unique, exceptionally safe, coding system and communication technique鈥, and heralded for its solving of the potentially dangerous issue of traction current interference.
The system has since been adopted by Network Rail - representing an unprecedented achievement for a UK company - and has generated worldwide sales in excess of 拢6 million per annum across European, Asia Pacific and American markets. Its success ensured the long-term viability of the Plymouth site, secured more than 60 jobs, and also resulted in the project winning the 鈥楰TP Business Impact Award 2011鈥, presented by the Technology Strategy Board.

On the achievements of the project

It was a very satisfying project to be involved with and the research will have applications beyond the railways.

Professor Martin Tomlinson.

Professor Martin Tomlinson

Alarms are another key component of the rail network, and it鈥檚 in this field - traditionally the domain of acousticians and engineers - that the University鈥檚 School of Psychology has played such a distinguished and influential role.

鈥淥ne of the most common responses from people when they hear an alarm is that it is too urgent or not urgent enough,鈥 said Judy Edworthy, Professor of Applied Psychology. 鈥淭hat level of urgency, which is communicated by a range of different acoustic parameters, is crucial to achieving the desired reaction.鈥

Years of research dating back to 1993 with colleague Dr Liz Hellier has established the pair鈥檚 reputation and generated a range of key insights, such as the way human speakers use those same acoustic parameters to indicate different levels of urgency, and that female speakers produce a greater range of urgency responses from listeners than male speakers.

When the Rail Safety and Standards Board (RSSB), the not-for-profit company owned by rail stakeholders, identified a range of issues around alarm implementation, they began to work with Plymouth鈥檚 psychologists through a series of commercial tenders commencing in 2004. It involved academics travelling the length of the country in trains to observe drivers in action and understand the issues at play.

The result was a remarkably comprehensive set of tools and guidance for rail professionals, including a good practice guide to the implementation of alarms and alerts, covering urgency mapping, alarm confusability, and considerations when implementing speech warnings. There was also an interactive alarm tool, some practical observations on the use of alarms in drivers鈥 cabs, and a sound library.

The success of the project, evidenced by companies such as Bombardier adopting the technology, resulted in a further project in 2010 when the RSSB invited Judy to design and document a new Train Protection and Warning System (TPWS).

On designing and documenting a new Train Protection and Warning System (TPWS)

There was a particular need to avoid confusion with other alarms, so we came up with a 鈥榥iche鈥 alarm that did not sound like anything else. Its frequency was modulated into a warble.

Professor Judy Edworthy

Professor Judy Edworthy

The work now provides the basis for a new national standard for TPWS alarms and has been mandated to be installed on all UK trains since 2012 and is already installed on some.