Imagine a world where you can travel at 500 km/h between major cities relaxing in comfortable seats, sipping a glass of wine, working on the laptop and walking to the buffet car. My work involves modeling the challenges that high-speed represents such as track dynamics and passenger comfort combined with minimising ground vibration and developing track forms that are fit for high capacity loading with the minimum of track maintenance requirements. At these high speeds we need to think about analysing the train and track as a combined system, i.e. we need to adopt an holistic approach to look at how the train is interacting with the ground and vice a versa.
The research we are undertaking is looking at how track deflections interact with the train suspension systems and hence how it affects passenger comfort levels. For high capacity lines, continuous use by high-speed trains can place high demands on the track components and we need to examine which type of track structure is most effective for a particular line and speed, both from an engineering perspective and from a financial perspective.
Compete at an international level
The Centre of Excellence for High Speed Rail has been set up by Heriot-Watt University and by Atkins to look at all of these issues. The new Centre will represent the ‘go to place’ for testing new ideas in high-speed trains and will allow the UK to compete at the international level in a rapidly developing global market for high-speed design and construction. The centre will be linked to some of the top research centres across the world and allow the development of international collaboration to push forward the boundaries of high speed into the realm of ultra-high speed.
Heriot-Watt University already houses the UK’s largest railway bed test track facility called GRAFT II (geopavement and railway accelerated fatigue testing). The facility is used by academia and industry to examine the long-term settlement behavior of track, particularly new track forms such as polymer reinforced track structures. The rig is capable of loading millions of cycles in a relatively short period of time at rates and loads similar to operational track conditions. It is currently being used for a project between the UK and
Japan for testing concrete sections of the Shinkansen high-speed lines under high loading regimes to examine the resilience of the concrete slab-track structures. In particular the tests will examine the behavior of the test specimens when subjected to high rates of loading (high train speeds) and vibration periods. The results will aid the development of new concrete structures and reinforcement technologies for ultra-high speed lines and allow direct comparisons between different track forms to be made.
A larger version of the test rig, GRAFT III, is currently being planned to allow research into the complete dynamics of track structures at full-scale and under laboratory conditions to be simulated. Together with the experimental facility numerical modeling using both in-house and commercial software is being used to look at the likely ground movement and vibration due to ultra-high speed passage. This links in very well with the experimental programme as all numerical programmes need to be calibrated and verified to particular track and train conditions. The research is cutting-edge but is leading the way towards the goal of operating trains at 500 km/h with zero carbon emissions.