400 UHC® HSH® (Mixed-Traffic, Metro & Light Rail Application)

The field of application of the 400 UHC® HSH® rail includes all areas of mixed traffic, the metro and the light rail sector, as well as turnout construction.

The UHC® steel design combined with the HSH® technology leads to a microstructure strengthening and refinement. The rail steel features highest resistance to degradation such as wear, corrugation and RCF, and is generally recommended for use in curves of railway tracks.

400 UHC® HSH® Product line (Heavy-Haul Application)

The high-strength 400 UHC® HSH® rail grade has been very successfully used in tracks with extreme load for years. It is applied especially in heavy haul transport with axle loads of 40 tons and more and has become the standard grade both for curves and for straight track. The top performance is proven in extreme environmental conditions from temperatures -40 °C to +50 °C, as well as in wear aggressive environment with sand in the rail-wheel contact area.

The field of application of the 400 UHC® HSH® rail includes also all areas of freight traffic.

The R290 GHT is a heat treated grooved rail steel, suitable for Gauge Corner Repair Welding. The low carbon content of the 290 GHT-CL especially facilitates gauge corner repair welding and makes welding as easy as for R200 rail steel.

While the well established R340 GHT already offers high resistance against rail wear, the new R400 GHT is characterized by the highest wear resistance of all grooved rail steels. This leads to longest service lives without the need for Gauge Corner Repair Welding.

When a wheel rolls over the rails, there are extreme contact strains put on the rail surface. Up to 20 tons load (weight of 15 compact cars, e.g.) are transmitted to the rail over a small contact between wheel and rail, a contact as small as the size of a 1 cent coin.

Therefore, enormously high stresses act on the wheel as well as on the rail surface, which lead to material changes. The result is high material deformation in the zones near the surface of the rail, and material properties change in such a way that rails become susceptible to operational damage. Rolling contact fatigue and rail wear occur.

High-strength rail steels, such as the 400 UHC® HSH®, are designed to withstand the high wheel/rail strains, and consequently the depth of deformation is greatly reduced. As a result, not only is wear reduced, but rolling contact fatigue is also successfully countered resulting in long service lives and reduced maintenance needs. Additionally, for the application in wide curves, the brand new rail steel 340 Dobain® HSH® can completely exclude these microstructural deformation mechanisms and the development of Head Checks is successfully prevented. 

The question of how big the influence of changes in rail hardness on the wheel wear resp. on entire wear of the wheel/rail system is represents a key question – for both, superstructure engineers and rolling stock engineers. Comprehensive research work at the TTCI (Pueblo, Colorado) in the 1980s showed that the use of harder rail steels in track does not influence the wear of railway wheels.  These results have been reproduced by extensive wear tests at the full-scale wheel-rail test rig of voestalpine Rail Technology, and have been confirmed by worldwide operational experience of railways.

All research work has in common that increasing the rail hardness does not influence the wheel wear, as long as the rail is harder than the wheel. This is the case for all nowadays-used rail grades, including the standard grade R260. While investigating a range of different rail grades, it is shown that the wear of the wheel is not increasing when using harder rails.

Using common rail steel grades as the basis for all further considerations, it is valid to state: The use of harder rail steels in track does not influence the wheel wear of trains.