To reveal the clip gain envelope set the Edit Filter Control to Clip Automation > Gain in the track header. For more info see http://www.cakewalk.com/Documentation?product=SONAR&language=3&help=Automation.11.html
 

I think what you are looking for is over on
the left of the screen.. when you click on a track.. on the left side of the screen is the console view of that one track.  In that strip.. the console view strip, you can adjust the fader to raise and lower the level of that track.  There is also the "gain" control up near the top of the console view of that strip.  As you highlight different tracks, the console view of the strip changes to which ever one you have highlighted..
 
hope that helps
BD