In Track View, the measures are displayed horizontally in one long scrolling view. There are no line breaks or page breaks in Track View and there is no limit to the number of tracks that can be displayed. You can display all tracks or any combination of tracks using the Track drop list found in the Notation Bar above the score.
Track View is often an easier way to enter notes into the score since you do not need to continually scroll the page left/right as you must when working with systems in Page View. Later, when you're ready to print the music you can switch to Page View for any fine-tuning adjustment to the appearance or location of musical symbols.