Track forces of iron ore wagons- Comparison Between Strain Gauge Based Measurements and Calculated Results

Sammanfattning: Iron ore trains run from the mine in Kiruna to Narvik and Luleå. These trains are subject to wear and have to be maintained. The wheel-­‐rail interface is a major cost-­‐driver in the maintenance. In Narvik, Norway  and  Sävast  outside  Luleå,  Sweden  there  are  measurement  stations  that  can  indirectly measure the forces that arise in this interface using strain gauges. However, it would save money if the wear could be predicted. It is therefore desirable to be able to predict the forces that arise in this interface.  For  this  purpose  a  model  of  two  coupled  iron  ore  wagons  has  been  developed  for simulations  in the Swedish multi body software Gensys. The aim of this master thesis was to take existing  measurement  station  results  from  Sävast  and  compare  them  with  simulations  of  trains running pn the same track section in order to evaluate and validate the model. To get as close to the measurement  station  results  as possible  several  different  parameters  such  as wheel  profiles,  rail profiles and friction coefficient were varied. Vertical Q forces, lateral Y forces as well as the Y/Q ratio were  evaluated  and  compared.  Longitudinal  X  forces  were  also  evaluated  in  the  simulations  for better   understanding   of   the   dynamics.   Comparisons   show   fairly   good   agreement   between simulations  and  measurements.  Calculated  Q  forces  end  up  in  the  mid  to  upper  spectrum  of measured forces. Y forces display good agreement with measured forces on all wheels except for the leading outer wheel. Measured Y/Q ratio is far above the calculated ratio.