Civil Engineering May 2021 | Vol 29 No 4

30 May 2021 Civil Engineering Professor Tawana Kupe, Vice Chancellor and Principal of the University of Pretoria (UP), has a vision that Engineering 4.0, together with the Hatfield and Hillcrest campuses, the Innovation Hub, and the CSIR, would be established as “the most innovative square mile in Africa”. Under the umbrella of smart transportation, the Chair in Railway Engineering is advancing the digital railway with Fourth Industrial Revolution (4IR) technologies. UP’s team of post-graduate railway re- searchers lifts the curtain on six of these technologies and describes how their work will benefit the railway industry in the years to come: 1. Digital twinning for railways 2. High-tech instrumentation for climate change 3. The Internet of Railway Things (IoRT) 4. Train (defect) detectives 5. Mapping and hovering with drones and LiDAR 6. Smart diagnostics with clever track components. DIGITAL TWINNING FOR RAILWAYS The digital twin concept involves the development of a computer-aided model which is similar to a real-life structure. The twin model is capable of solving complex problems using 4IR technologies. The concept was originally coined and presented by Dr Michael Grieve in 2003 at the University of Michigan, with a focus on product lifecycle management. The digital twin combines engineering model- ling with advanced analytics to create an intelligent model which responds to tran- sient changes in governing parameters. The key feature is the ability of the model to continuously adapt to changes in its environment using input data from real- time sensors to predict future behaviour of the physical asset. The operations of the railway industry rely heavily on various infrastructure components which would require a predictive and reliability-based approach for successful planned maintenance. The digital twin model therefore becomes a powerful tool for innovative asset management. However, the development of a robust digital twin model requires the combined use of elementary concepts of engineering and the following steps: Q Q Digitalisation of the physical geometry of the infrastructure Q Q Measurement of component behaviour using sensors Q Q Efficient data processing and analytics Q Q Intelligent models for predictive behaviour. A study, which implements ideas of the digital twin concept, focusing on increased axle loading on railway foundations, will be used as an example. Although the study is still ongoing and elementary, it is the beginning of the development of a robust digital twin model. The study focuses on the effect of increased axle loading on the behaviour of saturated and unsaturated railway foun- dation materials. Axle loading starts with 20 tonnes per axle as a base case with increased axle loading of 26, 30, 32.5 and 40 tonnes per axle. A finite element model has been developed for digitalisation of the physical geometry of the track struc- ture. The measurement of component behaviour, in this case of the subballast, involves the use of a cyclic triaxial appa- ratus instrumented with various sensors, as shown in Figure 1. The constitutive behaviour of the subballast material is elasto-plastic for saturated soil conditions Advancing the digital railway with 4IR technologies Dr David Mpye Chairs in Railway Engineering and Railway Safety University of Pretoria david.mpye@up.ac.za Rick Vandoorne Chairs in Railway Engineering and Railway Safety University of Pretoria rick.vandoorne@up.ac.za Daniel Pienaar Chairs in Railway Engineering and Railway Safety University of Pretoria daniel.pienaar78@gmail.com Chad Hawley Chairs in Railway Engineering and Railway Safety University of Pretoria hawleychad007@gmail.com Hein van Schalkwyk Chairs in Railway Engineering and Railway Safety University of Pretoria heinvschalkwyk@gmail.com The launch of Engineering 4.0 on 30 November 2020 at the University of Pretoria’s Hillcrest campus marked the start of an ambitious endeavour to realise data-driven smart cities and transportation networks. Ra i lway eng i neer i ng Prof. Hannes Gräbe Chairs in Railway Engineering and Railway Safety University of Pretoria hannes.grabe@up.ac.za André Broekman Chairs in Railway Engineering and Railway Safety University of Pretoria andre@broekmail.com