High-speed slab tracks put to 20m tonne axle test at Heriot-Watt



A slab track system that has been used in high-speed railways around the globe is being tested in Heriot-Watt’s Structures Lab to  discover whether it is suitable for UK conditions.

Eight sections of an FFB Bögl slab track system and its associated sub-layers are being tested on Heriot-Watt’s Geo-pavement and Railway Accelerated Fatigue Testing (GRAFT) facility, which uses hydraulics to simulate realistic speeds and dynamic loads of high-speed railways equivalent to many years of track use.

The slab track system is being tested over several weeks on the GRAFT facility. Scientists from the Railway Research team, with colleagues from the University of Leeds, will monitor the slab’s performance as the machine simulates the equivalent of 20 million tonnes of axle loading across the top of them.

The testing is the first of its kind in the UK and is being undertaken as part of the EPSRC-funded Lowering the Costs of Railways using Preformed Systems project (LOCORPS), which aims to reduce the cost of new high-speed railway lines  and improve track behaviour.

Professor Omar Laghrouche, Director of the Institute for Infrastructure and Environment at Heriot-Watt University, said: “The slab track and its sublayers are being subjected to the envisaged loading cycles of a UK high-speed railway, which will exceed 20 million tonnes axle load per annum.

“We’re looking at differential track settlement, which is a serious problem in modern day railway engineering, with considerable cost and time implications.

“Settlement of substructure is the main cause of track deterioration, and this research will identify how we can mitigate settlement and ensure future high-speed rail projects in the UK are appropriately engineered and constructed.

Professor Peter Woodward, Chair in High Speed Railway Engineering at the University of Leeds and head of the EPSRC-funded LOCORPS project, said: “High-speed rail lines, at ever increasing speeds and distances, are in consideration across the world, but up-front capital expenditure can sometimes be seen as an inhibiting factor.

“The LOCORPS project will bring us closer to innovative solutions that will reduce the cost and duration of construction, as well as the land take.”

Steve Swain, Project Director of Tarmac Max Bögl Joint Venture, was a supporter of the LOCORPS project and an advocate of the research. Steve added: “We were happy to support this research by providing both the FFB Bögl slab track system and the associated sub-layer materials, given the critical importance of high-speed rail to the UK’s future infrastructure plans and productivity across all regions.”

“Delivering these new networks safely and efficiently, with a focus on longevity and lifecycle costs is a priority, requiring proven technology and high-performance systems.”

Both plastic deformations and elastic behaviours of the track under various loading combinations are being plotted and the track structure is being monitored for probable faults. The performance of soil layers and super-structure layers are investigated.

The Geo-pavement and Railways Accelerated Fatigue Testing facility (GRAFT) is one of only two academic facilities of its kind in the UK. It has a hydraulic capacity of 200 tonnes (150 tonnes cyclically), which enables accelerated testing of existing and new railway products in realistic railway conditions.