The next generation in IRJ design and rail engineering

We had the opportunity to have a chat with Professor Manicka Dhanasekar (Sekar) and Dr Nannan (Roger) Zong of Infrastructure Engineering in the School of Civil Engineering at Queensland University of Technology prior to the RISSB National Rail Turnouts Workshop.

Pofessor Sekar has an esteemed and long career in academia including the publication of over 140 refereed research papers and Dr Zong is the winner of the Railway Technical Society of Australasia (RTSA) Wheel – Rail Interface award 2013 for his outstanding PhD thesis on optimisation of rail joints.

How would you describe an insulated rail joint to a non-engineer?
Insulated Rail Joint (IRJ) is a safety critical device in the signalling system of the rail track network intended for the detection of rail break or train location. It consists of two rail sections connected with two joint bars and six pre-tensioned bolts.  A gap between the two rail ends is absolutely essential to ensure electrical isolation of track circuitry. The assembly is made in factories and brought to site where they are welded in position.

Given its function, what are some of the specific maintenance issues associated with IRJs?
Appropriate handling and installation of the IRJs (new or replacement) are important as proximity to the sleeper positions affect the wheel – railhead contact-impact. A number of maintenance issues can be avoided with the correct installation processes; a best practice manual is essential for this purpose. Specific maintenance issues associated with IRJs includes:
– Examining the railhead ends at the joint gap for evidences of  metal flow/racheting of railhead and/ or delamination of the inserted end post material
– Check for the bolt tightness – any tendency towards loosening should be reported;
– Check for onset of cracks in jointbars
– Check for loose clips
– Check for damaged rail foot – sleeper interfacial pads
– Check for dirt/ carbon particle trapping in the gaps of loose endposts
– Check for mud pumping in ballast layer near the IRJ assembly
– Check for damaged ballast particles in the vicinity of sleepers close to IRJ assembly
– Measure the electrical isolation/ conductivity across the gap

What methods are available for monitoring IRJ performance and how reliable are these?
Progressive monitoring of IRJ is difficult in the field, because it requires physical inspection. An attempt was made in the USA with a trolley mounted camera system run on tracks taking digital images at regular intervals.  This method is not reliable as final data analysis of the images depends on the manual interpretation. Further data mining is a big issue.

What can happen when there’s a failure at an IRJ?
When IRJs fail, the detection of the train location cannot be fed back to the track circuitry. The track integrity/stiffness failure can cause derailment. Under these circumstances, new IRJs should be brought to site and welded in position to let the traffic flow. The section of the track needs to be closed during this period.  In peak hours, severe delays can cause societal problems and the loss of productivity. In case of derailment, casualty or spillage of chemicals can cause social/ environmental problems.

Looking specifically at Dr Zong’s research, what was the scope and aim of your study?
The scope of this research is to develop improved designs of IRJs through the investigations of the wheel-rail contact in the vicinity of the gap. The contact, stress and the structural deflections in the vicinity of the gap of the IRJs are of particular interest in this thesis. The numerical methods and optimisation algorithms used for developing the optimal shapes of the IRJ components are also examined for ensuring the efficiency and accuracy of the design optimisation procedure.

A sensitivity study of several key design and operational parameters is also included to justify the suitability of the improved designs in the field applications.

Are there any plans to commercialise the findings of your research?
Commercialisation of the new designs from my research is ongoing with the IP owner, CRC for Rail Innovation.

Many have commented on the perceived shortage of rail and track engineers for the Australian industry. Prof Dhanasekar, given your experience in research and development, what role does education play in bridging knowledge gaps in industry?
Education is a key to knowledge and sustainability of the privileges we enjoy as the society.  Education must occur at all levels at world-class standards to keep the nation competitive.  Very little education on track engineering/ rail technology occurs at undergraduate engineering levels at Australian universities.  Graduates are trained by the industry.  Relatively, the building industry benefits from tax payers’ dollars as most civil engineers graduate with a good understanding of the design and construction of building elements and systems in concrete/ steel/ masonry and timber.

At the research level, since the establishment of the Rail CRC, some 100+ PhDs and Master-qualified graduates have emerged.  Unfortunately only a tiny % of these (post) graduates have been absorbed into the work force in spite of their wider and deeper knowledge in rail system engineering. Rail is a very complex engineering system.  Often a change to one element (for example insertion of geogrid in ballast – capping layer interface) can lead to significant increase in the response of other elements (for example the wheel-rail contact force).  Such an integrated, yet not well researched system offers a lot of research opportunities.  The universities have a lot to gain with that type of research. For example, Queensland University of Technology (QUT), with its strength in infrastructure research, is offering “Track Infrastructure” postgraduate coursework master degree, which is unique in Australia.

There is also the related issue of attracting new researchers to the industry. Dr Nannan, what attracted you to the field of engineering research?
I am passionate about solving and eliminating problematic issues in engineering creatively. Rail engineering research provided me with the opportunity of exhibiting my passion. I ended up developing novel design solutions to the safety critical elements in the track structure. My strong background in undergraduate and master level studies in engineering provided excellent foundations to solve the real world complex rail engineering problem in my PhD. I derive great personal satisfaction with my endeavours as my research findings are appreciated by the industry through the announcement of the winner of the RTSA Wheel-Rail Research Award 2013. In the long haul, I believe I have the energy and knowledge to contribute to the industry to further improve our community and the sustainability of our rail industry.

Professor Manicka Dhanasekar (Sekar) and Dr Nannan (Roger) Zong, QUT will deliver a presentation on longer life IRJs at RISSB’s National Rail Turnouts Workshop in Newcastle on the 29th & 30th May, 2013.

For more information, please visit the RISSB National Rail Turnouts Workshop website and the RISSB Wheel Rail Interaction Forum website.

In addition, for information on QUT’s engineering research courses, visit their website here.