Home Reference Manuals Up Return

# 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: `tar -tzvkpf r200_exit_derail.tgz`
  - Extract the contents of the tar-file: `tar -xzvkpf r200_exit_derail.tgz`
- or the zip-file r200_exit_derail.zip
  - List the contents of the tar-file: `unzip -l r200_exit_derail.zip`
  - Extract the contents of the tar-file: `unzip r200_exit_derail.zip`
- or go directly to the files: r200_exit_derail

## 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.