I know how to use envelopes and gain increase/decrease but I was wondering if one can simply find a "too loud" section, split the track just before and just after the too loud section and then simply reduce the overall volume by dragging the top of the track downward like I can do in my Sony (Magix) Vegas video software and like I think Protools can do? I know I can do a ramp-up or ramp-down by dragging out the little triangles in the upper corners of clips but there doesn't seem to be a way of dragging on the track to do this process. Maybe that function was added to recent updates that I missed out on. I have Platinum but my updates ended March 2017.

https://www.cakewalk.com/Documentation?product=SONAR&language=3&help=Tools.23.html#1378431
 

The other way is to go to "process" menu, then "audio" and then gain. Note that applying this on a portion of audio clip:
1) you might have less precision to balance the portion gain with the remaining parts of the clip;
2) this process is destructive.
 
The Skook link describes the better way to operate.

Thanx for the responses. I learned about this below but it doesn't seem to lower the height of the actual waveform image as one pulls it down like I think it can do in Protools but it will suffice. I had also been doing this type of thing using Melodyne which does seem to resize the waveform image but of course you have to take the time to put the clip into Melodyne.
 
To raise/lower an audio Clip Gain envelope
1.
Set the track’s Edit Filter control to Clips.

2.
Select the Smart tool .

3.
Position the mouse pointer over the top half of the clip until the pointer looks like this , hold down the CTRL key and drag up/down.

Actually, the fade tools with the little triangles perform almost exactly like I want but they only do fades (in or out). I was hoping there was a way to do that with the tool and do it "horizontally" across an entire clip and see the waveform shrink and/or expand while I moved the tool up and down in trackview. Anyway to do this?

It's been requested many times and it never happened, would have been nice,  Then next best/better thing cost money, upgrade to melodyne assistant and use the amplitude tool.  You can change volume of a single note or select multiple notes without zooming in and being so careful of what you select.  Lot's of other nice features if you're interested in that kind of stuff.