Thorsten, thank you, that gets me close to what I want, but there are still two issues with this process. First, let me clarify that the total distance of this project is from Milepost -15 to +19. The project spans a section of track that was originally built several decades ago by two different rail companies, but today is now own by one. Because two different companies built the track, the Milepost markers were not consistent. The mileposts for the western portion of the track go from -15 to -7. At that point, the mileposts readjusts, and go from -8.3 to +19 for the eastern portion of the track. Basically Milepost -7 for the western portion of the track is the same point as Milepost -8.3 for the eastern portion of the track. I know, its confusing.
Anyway, since I need to show both scales in my view, I created two sub-projects, one for the Eastern side and one for the Western side, with their unique distance scale. I am including an image to show where the point the mileposts change.
Going back to my original question, I need to do this twice, one for the western side and again for the eastern side.
My first issue, starting with the western side and following your instructions, when I changed the distance scale to from -15 to -7 to -9 to -7, the image did adjust, but not in the matter I wished. I wanted to continue to see the entire height of the image, but only from -9 to -7, but instead the image appeared to zoom in on the image, showing only the top of the image.
Before
After