Liebherr-Transportation Systems, in association with their consortium partners, the UK rail company Grand Central (part of Arriva Group) and NewRail (Centre for Railway Research at Newcastle University), conducted the initial testing of the LiCAS demonstrator. The aim was to demonstrate that LiCAS could protect the infrastructure, i.e. that wear of track and wheels can be significantly reduced compared to that of conventional suspension systems. Rail transport operators can thus save money on track fees per kilometer (such as those charged in Switzerland and in the UK), as well as on operating and maintenance costs, as the maintenance intervals of wheels can be extended.
A BT10 bogie on a Mark 3 coach from Grand Central was equipped with the active radial steering system. The test runs on the 18 mile Weardale Railway, in the UK, fully confirmed the expected positive impact of LiCAS on the behaviour of the bogie, as it was previously determined by multi-body modelling and simulation work.
In particular, it has been demonstrated that LiCAS considerably reduces the so-called “angle of attack”, even in the narrowest of curves. This means that wear of the wheel and rail would be significantly reduced in the relevant curves with low radii, and sections of railway with switches and crossings undergo significantly less mechanical stress. The simulations and test results showed that, depending on the curve radius, the contact patch frictional energy, Tγ, which is a relevant wear indicator, is reduced by at least 50 % on bogies equipped with the active radial suspension system. This means that, in addition to protecting the infrastructure, the wheelset maintenance intervals can be extended by up to 30 % and, depending on regulation for specific railway networks in each country, a significant reduction in fees per kilometre travelled can be attained.
The core of LiCAS is a compact, hydraulic actuator that has the same size and shape as a conventional swing arm bush and can therefore be integrated in many bogies currently in use. In addition, one hydraulic supply unit with integrated electronics per bogie is required for the system.
“In comparison to any passive control system available today, our active system is much more effective, since it can be optimally adapted to the individual curve radius and the different regional track-wheel geometry of the tracks”, explains Paul Hofbauer, Product Manager Hydraulics at Liebherr-Transportation Systems.
