PolyU technology tested on high-speed railway

PUBLISHED : Tuesday, 12 July, 2011, 12:00am
UPDATED : Tuesday, 12 July, 2011, 12:00am


A system of fibre optics in lieu of conventional electronic sensors has been tested on the Beijing-Shanghai high-speed rail line and found to be effective in relaying track information to conductors, at a fraction of the cost of current technology.

The result means the sensors could be installed on lines nationwide in the hope of improving the structural integrity and safety of the high-speed rail network.

The system was built by researchers at Hong Kong Polytechnic University and two mainland universities - Southwest Jiaotong University and Dalian Jiaotong University.

Professor Alex Wai Ping-kong, PolyU's vice-president of research development, said yesterday that: 'Test rides done last month boosted our confidence in the system. We hope it will be used all across the mainland. And then all over the world.'

More than 100 optical sensors fitted on a rail can provide real-time information on vibrations, acceleration and temperature change for engineers, helping them monitor the conditions of tracks and trains, as well as the structural health of the rail foundations.

'When we detect problems, we'll tell the train driver to slow down right away,' said Professor Tam Hwa-yau of the department of electrical engineering, who developed the system and led the study. 'The Beijing-Shanghai line has just begun to operate, so there should be very few problems. But given time, the rail will take a lot of wear and tear, and our system will scrutinise every small change at all times.'

Wai, also a leading professor of optical communications at the university, said that companies had shown an interest in buying the system, but tests and certifications would take at least three years.

PolyU began researching fibre-optic sensing in 1994, when it was thought such technology could be used only to measure temperature. But the technology has improved radically and now lends itself to a wide range of fields, including sensing systems, life sciences and structural engineering.

Under the PolyU system, hundreds of sensors are fitted along a single optical fibre as long as 100 kilometres to measure various parameters. This single system does the work of many conventional sensing systems, and at a 'much lower' cost, Tam said.

The sensors detect changes in wavelength, and their signal strength does not affect the sensing information, making it highly reliable, Tam said. The sensors are attached to tiny optical fibres and are also not affected by external interference such as bad weather.

Wai said participation in mainland railway projects was usually limited to allied universities - such as the two collaborating ones - to protect technological secrets.

Since PolyU pitched the idea to the two universities two years ago, it had faced some difficulties in winning the trust of mainland authorities, Wai said.

'Big projects like this are highly coveted among mainland universities. It wasn't easy for us to get the opportunity to be a part of this,' he said. 'Now we've done it and we are very honoured.'