Researchers revolutionising railway sleeper design

Jul 06, 2007

Innovative research by engineers at the University of Wollongong is set to change the design concept for railway tracks’ concrete sleepers and possibly save the industry millions of dollars.

Dr Alex Remennikov from the School of Civil, Mining and Environmental Engineering and his PhD student (and teaching academic), Sakdirat Kaewunruen, are completing the research in collaboration with Queensland University of Technology and have been sponsored by the CRC for Railway Engineering and Technologies (RailCRC).

The railway sleeper is a major component of railway tracks. It is the crosstie beam built to distribute the load from the rails to the underlying ballast bed. Although the sleepers can be made of timber, steel, or concrete, the current trend is the large utilisation of the concrete sleepers because of its high durability and high benefit cost ratio.

“Concrete sleepers can last from 50 to over 100 years under extreme environmental conditions – for example weathering, temperature, or moisture,” said Mr Kaewunruen. “The high mass of the sleepers also help stabilise the railway tracks from thermal expansion of rails and vibration of rolling stocks.

“The initiative of this research project came from a widespread notion based on general industry experience that concrete railway sleepers have reserves of untapped strengths. The current design concept of concrete sleepers has been guided by experience – with little science or theory to back it up. This has resulted in an overestimation of strength requirement, and a consequent high cost for their extensive use.”

As part of the research, a new high capacity drop-weight impact machine was constructed at UOW. This impact testing facility is currently the largest of its kind in Australia, with the maximum drop height of up to 6m.

It can accommodate full-scale building/structural members such as the concrete sleeper, steel-concrete composite beam and column, or precast concrete slab. High technology sensors and devices are in place to measure and monitor the behaviour of any test specimen under a variety of dynamic impact loading spectra.

An estimate by STEM partnerships (2006) showed that the new design concept would help the rail industry save over seven million dollars in a short run.

“Saving a few dollars per sleeper seems insignificant, but when considering the millions of sleepers used for rail network construction and maintenance, this research project is highly significant for the economic viability and future of rail. It proposes a new design philosophy for railway track design that is more reliable and economical, and evaluates the ultimate capacities of concrete sleepers under more realistic loads.”

For more information contact Dr Alex Remennikov on 0407 410 290 or Sakdirat Kaewunruen on 0413 736 904

*Media please note: A high-resolution photo of Dr Remennikov and Mr Kaewunruen ‘in action’ is available by contacting Renee Criddle in the Media Unit on (02) 4221 3290.

For more information, contact:

media@uow.edu.au
University of Wollongong
Ph: (02) 4221 5942; fax (02) 4221 3128