changes around drag coefficients
At the moment there is track drag which is the rolling drag between the train and the track, but the physics needs the drag force for a standing force to be able to calculate the force it can accelerate with. The documentation and train class should be update to reflect the following:
-
track_drag is the drag coefficient between a rolling train and the track -
train_drag is the drag coefficient between a standing train and the track -
The drag should be returned by the Track_configuration to allow modifiers like rain -
track_drag should be defined in the Track_data since it may vary along a track