University of Huddersfield researchers have outlined how they have optimised London’s upcoming Elizabeth line underground route to lower maintenance costs associated with the inevitable wear and tear of having so many trains run across the tracks every day.
The new £14.8bn Elizabeth line is expected to become operational in December 2018 and will carry an estimated 200 million passengers a year. At the University’s Institute of Railway Research (IRR), assistant director Dr Paul Allen has been working on the project since planning and design stages in 2008. The first phase of his research led to changes in the cant – the height of one rail above another in curved track.
On curves, a carefully-calculated reduction in cant helps to even out the forces across the many axles of a train, reducing the risk of rolling contact fatigue (RCF) in rails, a problem which accounts for a significant proportion of Network Rail’s annual maintenance budget on mainline track.
“The reason this was a major issue is that the typical curve radius on the Elizabeth line route is about 500 metres, where it might be about 1,000 or 1,500 metres on a typical main line,” Allen said. He added that the Elizabeth line also has a particularly large number of curves and it will be carrying huge amounts of traffic – an average of over 380 trains a day.
In order to maintain this capacity, it is important to minimise disruption caused by unplanned maintenance. Exhaustive simulations and calculations have been carried out which have led to changes in track alignment that will reduce both wear and the potential for RCF in curves.
However, some wear and RCF will still occur and Allen, with his IRR colleague Dr Philip Shackleton, has continued to work with Transport for London (TfL) in order to develop a maintenance planning tool for the Elizabeth line.