Timeline View also lets users make loudness gain adjustments by simply adding/adjusting loudness handles.
Adding Loudness Handles:
To add loudness handles simply go the position in the waveform and press "Ctrl+LeftMouseClick" on the line right above waveform.
Dragging the loudness handle also shows loudness value in the tooltip.
Removing Loudness Handles:
Simple double click on the handles remove them.