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.