Of-round wheels, polygons, flats, noise complaints from residents, use restrictions
- An issue in your company?


Might occur during use out-of-roundness (polygons) on individual wheels. Polygons can be heard as a booming rolling noise relatively uniform volume and stimulate vehicle components (eg inner lining, floor) to vibrations at. Polygons impair travel comfort and create an additional vibration stress of certain components. This should be eliminated by turning or rotating milling on an underfloor wheel processing machinery. Polygon formation is not only a geometric runout, but causes an inhomogeneous distribution of hardness in the wheels. If these embrittleed are not removed during processing, the wheel will be out-of-round (memory effect) once again after a short period of operation. Thus, a material removal of about 5 mm for the permanent removal of the relatively small eccentricities is required, which means a considerable economic loss in wear stock of the wheel of 40 mm.

A flat section is formed when the wheel of the moving vehicle does not longer roll, but slides over the rail ("slide"). By flats and polygons result very high dynamic forces with a plethora of serious consequences for rails, superstructure and vehicles:

  • Risk of rail breakage when driving through occurring "blows" (mainly in frost periods).
  • Damage to the track geometry - The influence of the applied force spectra into the track on the track quality decay rate can not be overestimated. Therefore, the planned route for an operation and the rolling stock used has a great influence on the frequency of maintenance work to be performed and the associated costs. A wheel load fluctuation of 30% is already attracting a 1.6-fold faster track geometry deterioration after themselves. This means that vehicles with out-of-round wheel units or ride instability damage the track disproportionately. There are also reductions because of the "liquid becoming" (elastic-liquid behavior) of the ballast at frequencies above 40Hz.
  • False brinelling refers to the emergence of wavy indentations in the driving mirror of railroad tracks. The causes are varied, more often they come about by abrasive wear during braking and cornering of trains and irregularities of the wheels.
  • During the trip can be heard a periodically occurring noise in the frequency of the wheel rotation.
  • Development of common annealed flat spots on the wheel tread.
  • Creation of plots, that is to say of the rail surface abraded and usually right in front of the flat section on the wheel, or elsewhere on the wheel material applied may result in the worst case to wheel lock (canting of brake blocks).
  • Blows caused by flat spots, also influence the components of the axle box -> Bearing damage and hot runner.

Out- of- roundness or flats of a railway wheel have a negative effect on the smooth running and wear on the wheel and cause additional noise for residents. Therefore, the German Federal Government is pursuing a national noise target of halving poverty by 2020 is expected to emission-based track access charges and from 2020 onwards with use restrictions for non-compliant vehicles. The pressure of the residents and communities of interest is continuously increasing and has an impact on travel times, costs and returns. The noise reduction is a key issue for the rail system. In train sets emission and sources of damage must be detected wheel- and polluter exact. What action is required?


Purchase of train and wagon-related and wheel accurate data for condition-based maintenance of wheelsets - in Germany from the DB - who captures the driving qualities by means of the fully automatic wheel force diagnostic and video detection systems LASCA®, MONI and MOVIE and can provide without  any discrimination.

  • Condition-based maintenance of the entire fleet - smooth running characteristics.
  • Wayside train monitoring as a substitute for manual runout measurements - Cost reduction for the same security.
  • Increase the mileage of the wheels through the timely reprofiling at a lower depth of cut - reducing costs by exploiting the scheduled mileage.
  • Reduction of dynamic forces in operational use to protect the infrastructure and vehicle fleet - Avoidance of wheel and rail breaks.
  • Timely detection of flat spots and out of roundness (polygons) to prevent the hardening to the tread - hardening means increased depth of cut at the reprofiling.
  • Detection of wear-causing variations in the running behavior of the vehicles - load shifts of the axles and bogies, incipient wheel flanges, defective shock absorbers.
  • 100% monitoring of the fleet under operating conditions in the dynamic running behavior - Cost reduction through planned proactive vehicle management and utilization of re-profiling and workshop capacity while reducing downtime.
  • Reducing sound and vibration emissions - particularly noise and residents' complaints - filtered data release to increase acceptance.
  • "The most monitored fleet" - by the German TÜV certified monitoring system.


  • Improving comfort for the passengers.
  • Reducing noise levels for the residents.
  • Protection of sensitive railway facilities.
  • Significant resource and cost savingsin maintenance.
  • Lower track price.