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Derailment in a transition curve due to wheel unloading

• Introduction
• Download the example
• Run the examples
• Animate the results in GPLOT

Introduction

A BoBo-vehicle passes a right handed curve. The run-on and run-off transition gradients are 1/300. The vertical stiffnesses of the vehicle are relatively stiff, causing severe wheel unloading both in the run-on and the run-off transition curve. The vehicle passes the run-on transition curve, because in this curve the wheel unloading occurs on the inner(lower) wheel. The run-off transition curve is more critical, because in this curve the wheel unloading occurs on the outer leading wheel.

The runf-directory has two input data files with different vertical stiffnesses in the primary suspension. The stiffer input data file runf/R200_dip20_stiff_3.0.tsimf derails but the softer input data file runf/R200_dip20_stiff_2.9.tsimf returns back on track again.

Download the example

• Download the tar-file r200_exit_derail.tgz
• List the contents of the tar-file with "tar tvfkz r200_exit_derail.tgz"
• Extract the contents of the tar-file with "tar xvfkz r200_exit_derail.tgz"

Run the examples

• Double-click file runf/R200_dip20_stiff_2.9.tsimf and select open->run with the right mouse button.
• Double-click file runf/R200_dip20_stiff_3.0.tsimf and select open->run with the right mouse button.
• As output the following files will be produced:
• As output the following files will be produced:

  id/R200_dip20_stiff_2.9.id	MPdat-files for plott- and post- processing in program MPLOT
  id/R200_dip20_stiff_3.0.id
  gp/R200_dip20_stiff_2.9.gp	GPdat-files for animation in program GPLOT
  gp/R200_dip20_stiff_3.0.gp

Animate the results in postprocessor GPLOT

• Double-click directory runf/ in the subdirectory text area.
• Double-click file runf/R200_dip20_stiff_2.9.tsimf in the file text area.
• Press the Gplot-pushbutton.
• Open file gp/R200_dip20_stiff_2.9.gp by selecting File->read_GPdat in the pulldown menu bar
• In the pulldown menu bar press View->show_4_diag in order to show a close up view of the wheel/rail contact
• Start the animation by pressing the Fwd–pushbutton.
• When the first animation is finished open file gp/R200_dip20_stiff_3.0.gp in the same way as gp/R200_dip20_stiff_2.9.gp. Start the animation and compare the differences between the two cases.