Another way to get volume changes on a track is to use the "volume nodes". To see these, move your mouse pointer to the bottom of the track you are working on until the pointer turns into a double arrow.

Click on the bottom of the track and drag it down until a blue horizontal line is seen at the bottom of your track. On the left, click the drop down arrow and change from 'Gain Nodes' to 'Volume Nodes'.

Now you can click on the blue horizontal line to place volume nodes, drag the horizontal line up or down for that section of track you wish to change the volume of. I've been using these volume nodes for several years now and they work reliably to change the volume of a section of track.

I've also used the way Charlie mentioned and that works well also.

Del