The Tracking Gantt view displays two task bars, one on top of the other, for each task. The lower bar shows baseline start and finish dates, and the upper bar shows scheduled start and finish dates. Or, if the task has already started, meaning that the percent work complete is greater than zero, the upper bar shows the actual start and the date through which work has been completed. If the task is 100% complete, the upper bar shows the actual start and finish dates.
Best uses Use the Tracking Gantt view to:
- See how tasks progress across time and evaluate the slippage of tasks. You can track progress by comparing baseline and scheduled or actual start and finish dates and by checking the completion percentage of each task.
- View tasks graphically while still having access to detailed information about the tasks.
- View dependencies between tasks.
- View assigned personnel and other resources to tasks.
For planner products only:
- Create a project by entering tasks and the amount of time each task will take.
- Establish sequential dependencies between tasks by linking them. When you link tasks, you can see how a change in the duration of one task affects the start and finish dates of other tasks, as well as the project finish date.
- Assign personnel and other resources to tasks.
Tables The sheet portion displays categories of information about the tasks, arranged in tables. The default table for the Tracking Gantt view is the Entry table, but you can select any of the task tables to display information about the project's tasks.
Filters The Tracking Gantt view can use any of the task filters to display only the tasks you want to see. When you select a filter, both the sheet and chart portions of the Tracking Gantt view display the information as defined by that filter's criteria. The default filter is the All Tasks filter.
Sorting You can apply different sort criteria to the tasks from the Tracking Gantt view.
Grouping  The Tracking Gantt view allows you to group tasks.
Zoom in and out 
The timeline units for the right portion of the Tracking Gantt view are displayed at the top of the chart. By default, displays two units of time. You can adjust these time units to display up to three units of time, and you can change it so that different time units are displayed. For example, you can zoom out to get a bigger picture of your project's tasks by displaying Years and Months, or you can zoom in to see the exact start and finish dates for your project's tasks by changing the timescale to Weeks and Days.
Additionally you can choose a custom value for the zoom level.
 This option is available only in Project Viewer for Win PC/Server, Project Viewer for Win Web/Server, Project Viewer Online Subscription, Project Viewer for SharePoint Server, Project Viewer for SharePoint Online, Project Plan 365 for Win PC/Server, Project Plan 365 for Win Web/Server, Project Plan 365 Online Subscription, Project Plan 365 for SharePoint Server and Project Plan 365 for SharePoint Online products