Simple enough:

$("#tbLog tr.private").action();

If you have sub tables (why?), then use this instead to only select the top level trs

$("#tbLog > tbody > tr.private").action();

Note that I've included tbody in the selector as nearly all browsers will add this tag for you (it's part of the spec).

This how it's done:

$('#tbLog tr.private')

This way?

$("table#tbLog tr.private")