Prof Hannes Gräbe, Head of the Department of Civil Engineering in the University of Pretoria’s Faculty of Engineering, Built Environment and Information Technology, delivered his inaugural address on 31 October 2023. The topic of his presentation was “Tracks of discovery, innovation and education: Inspiring a new future for railway engineering”.

Prof Gräbe is a registered professional civil engineer with experience in track technology, track geotechnology, advanced laboratory testing, field investigations, maintenance models and the numerical analysis of track structures. He is also the Chairholder of the Railway Safety Regulator Chair in Railway Safety.

In his presentation, Prof Gräbe explained how the railway structure’s foundation, supporting ballast, sleepers and rails significantly influence load-carrying capacity and the quality of a journey by rail. While laboratory settings facilitate the development of innovations in this area, industry applications necessitate the ability to measure track component performance through sensor technologies on operational railway lines. He explained how innovations in this field have focused on smart railway monitoring and smart track components. This followed the development of optics, sensor technologies, communication protocols, artificial intelligence and machine learning.

Presenting some of the innovations in track condition monitoring developed in the Department, he explained how use was made of a “smart ballast stone” to give researchers insight into the complete three-dimensional formation stress regime brought about by the movement of the train. This enabled them to monitor the transportation of fresh produce such as tomatoes and avocadoes. It entails a 3D-printed shell housing a minute battery-powered, wi-fi-enabled wireless microprocessor with onboard storage and high-frequency sampling. This device can record rotations, accelerations and magnetic flux in three directions, allowing researchers to advance from remote video monitoring to inertial measurements of track deflection as a result of dynamic train loading.

A second smart track component that is used is a 3D-printed rail pad instrumented with two accelerometers and a half-bridge strain gauge. The accelerometers detect any wheel or rail irregularities, while the strain gauge measures the load transferred from the rail to the sleeper. The smart rail pad functions as a remote condition monitoring system with a micro-controller mounted to the rail that records data from the strain gauge and accelerometers. It has an automatic triggering system that allows it to remotely measure railway traffic without human intervention, producing accurate wheel load results for weighing and impact detection.

Another innovation is the use of light detection and ranging (LiDAR) to identify and segment water leakage in railway tunnels. The LiDAR scanner records up to 300 000 points per second and produces a point cloud in 3D with an indication of the intensity of the reflected light. The variance in the reflection of light from dry to wet surfaces allows researchers to track moisture and water leaks in dark, inaccessible tunnels, enabling remote data analysis.

Yet another innovative study aimed to determine whether track geometry can be derived from optical measurements instead of conventional, costly geometry vehicles and inertial measurement systems. This culminated in the development of three innovative smart track instrumentation systems. These entailed a system to acquire the photographic sequence of the rail, a low-cost, centimeter-accurate GPS and a neural network pipeline that produces the 3D reconstruction of the rail profile. These innovations enable researchers to deduce track geometry with reasonable accuracy, comparable to conventional instrumentation.

In addition to projects focused on autonomous track structure monitoring, the Department recognised the possibility of using its road-rail vehicle to benefit research in other disciplines as well. A research project was conducted in collaboration with ecologists in Mpumalanga to mitigate train-wildlife collisions in the greater Kruger National Park. By mapping the rail reserve and infrastructure assets, a digital infrastructure inventory of the railway line and adjacent area was developed to identify factors that contributed to collisions with wildlife on the railway line, which caused damage to the train and posed risk to human life.

Prof Gräbe concluded his overview of research in railway engineering by discussing the concept of a digital railway for research purposes. This involves the use of digital twins, augmentative and virtual reality training, Big Data and deep learning. He explained that digitalisation transcends the mere application of digital technologies. It revolves around people, making them central to the transformative concept. This enabled researchers to design a real-time track condition monitoring system for the Gautrain in 2022.

Training practitioners for the challenges that lie ahead for railway engineering is essential for a sustainable rail industry in South Africa: both in terms of freight transport and passenger rail. This includes making use of three railway test tracks constructed on the University’s Hillcrest Campus. In this way, postgraduate and continuing education training programmes can incorporate practical examples to provide hands-on experience that emphasises safety, creativity and engineering skill.

The underlying vision of the University’s postgraduate railway engineering programme is to make railways work better for the common good, and as such, it is making an impact in inspiring a new future for railways in South Africa.