Systems used to detect aircraft and ships could soon be fitted in train stations to quickly identify objects - or even people - that have fallen on the tracks, preventing serious accidents and reducing delays that are frequently caused by these mishaps.
Used in conjunction with CCTV, which can often blur or become obstructed, a radar device could quickly identify luggage items that regularly fall off station platforms and in the event of a person falling on the tracks, feedback to a system that stops oncoming trains and cuts the high voltage of the lines.
The detection system, demonstrated today, 6 January, in IOP Publishing's journal Measurement Science and Technology, sends ultra wideband radio waves towards objects and then records them as they bounce back, revealing the intricate characteristics of the object in question.
"The aim of the system is to identify any objects or persons that may have fallen onto the tracks. In a large, capital city underground, this can happen two to three times a week and lead to significantly long service interruptions.
"With the possibility of trains, passengers and even poor lighting, in some instances, obscuring the view of CCTV cameras, radar techniques could certainly be effective in these scenarios," said lead author Ali Mroué.
The researchers, from IFSTTAR and IEMN, in the framework of the Université Lille Nord de France, used an Automatic Target Recognition (ATR) procedure whereby the characteristics of an object are defined and then trimmed down so only the most important ones are stored. The characteristics are then compared to those of other objects on a database, with the overall classification depending on the degree of similarity.
Using a computer model, the researchers initially tested out a number of objects, ranging from suitcases to glass bottles, and several models of the human body: an adult, a teenager and a child. In the simulations, the radar was able to successfully discriminate between the different objects, confirming its applicability.
Real-life experiments were then performed in a small, echo-free chamber, using a three metre long waveguide - a solid beam-like structure that guides the radio waves in a certain direction; in this case, towards the object you are measuring.
In these experiments, three humans were used - two men and one woman - along with two luggage bags made of different materials. The system successfully differentiated between the luggage bags and the humans, meaning a potential system could highlight the urgency of a response.
"We hope these devices will be used in the near future since they are very complementary to existing video systems and have a similar final cost. The complementary use of video and radar systems could lead to low levels of false detection, which is mandatory for this application, and maximise the chance of survival for passengers who have fallen on the line," continued Mroué.
From 6 January, this paper can be downloaded from
Notes to Editors
1. For further information, a full draft of the journal paper or contact with one of the researchers, contact IOP Publishing Press Officer, Michael Bishop:
Automatic radar target recognition of objects falling on railway tracks
2. The published version of the paper "Automatic radar target recognition of objects on railway tracks" (2012 Meas. Sci. Technol. 23 025401) will be freely available online from 6 January. It will be available at http://iopscience.
Measurement Science and Technology
3. Measurement Science and Technology covers all aspects of the theory, practice and application of measurement and sensor technology across the sciences.
4. IOP Publishing provides publications through which leading-edge scientific research is distributed worldwide. IOP Publishing is central to the Institute of Physics, a not-for-profit society. Any financial surplus earned by IOP Publishing goes to support science through the activities of the Institute. Beyond our traditional journals programme, we make high-value scientific information easily accessible through an ever-evolving portfolio of community websites, magazines, conference proceedings and a multitude of electronic services. Focused on making the most of new technologies, we're continually improving our electronic interfaces to make it easier for researchers to find exactly what they need, when they need it, in the format that suits them best. Go to http://ioppublishing.org/
The Institute of Physics
5. The Institute of Physics is a leading scientific society promoting physics and bringing physicists together for the benefit of all.
It has a worldwide membership of around 40,000, comprising physicists from all sectors, as well as those with an interest in physics. It works to advance physics research, application and education; and engages with policy makers and the public to develop awareness and understanding of physics. Its publishing company, IOP Publishing, is a world leader in professional scientific communications. Go to www.iop.org