This is roughly the scale at which things are displayed on screen. This is not to be confused with your modeling scale.
Don't rely on this for precise measurements, as the actual sizes depend on the size of your monitor.
To zoom in or zoom out
1.Locate the View Scale slider in the lower right corner:
2.Move the Slider to change the view scale.
1.Click the tab.
2.Select a View Scale.
TIP: For fast zoom, press CTRL and use the mouse wheel
TIP: To zoom using the keyboard, press CTRL + or CTRL -
NOTE: This setting has nothing to do with the train scale i.e.: TT, O, H0, etc. The train scale depends on which track library you use