There may be some giant objects in the old drawing that you
did not realize were there. For example, you may have made a
line by accident that is 9999999 feet long and you don't see the
object in Version 5. When you open the drawing in version 9,
Cadrail uses the Show All Objects feature and then you don't see
anything on the screen because the view is so big. Turn on the
object labels display and then zoom in on the "dots", that is
where the drawing is at a large scale and more will be visible
when you zoom. To correct the problem, delete the giant objects.
Use the menu item Edit - Input Object Number with the Delete
tool if you cant click on the object(s) to select it.