Ultrasonic system saves costs

Cape Town - A system preventing trains from becoming derailed has been developed by the Council for Scientific and Industrial Research (CSIR) as a world first and is already in use by Transnet.

In the past financial year the CSIR prevented derailments that might have cost Transnet around R100m and placed coal and iron ore supplies under pressure.

According to the CSIR annual report for the 2010/11 financial year this innovation, based on ultrasonic technology, is already operating on parts of Transnet’s coal line between Ermelo and Richards Bay, involving 460km of rail track.

The system is also being used on parts of the iron ore line between Sishen and Saldanha (over 860km).

It can sense where faults and cracks resulting from fatigue and continuous welding appear in the railway line.

The report notes that in South Africa, as in the rest of the world, rail infrastructure is old and expensive to replace. The rate of derailments therefore increases.

According to the report, each derailment in South Africa costs the economy around R50m.

The CSIR’s system has already been tested on New York and Hong Kong’s train subways. It is currently also being tested in Japan.

An estimated 60% or more of all rail systems in the world could use this technology – involving about 673 500km of rail.

The CSIR’s system is based on ultrasonic technology. It consists of equipment to convert electrical signals into ultrasonic sound waves and the sound waves back into electrical signals.

Ultrasonic waves are transmitted along the rail. Various sound “stations” are situated along the line. If a particular station fails to receive the ultrasonic signals an alarm goes off, showing a break in the line.

The CSIR says that the rest of the world is currently testing various methods to prevent derailments, but these involve labour-intensive devices.