Changing the volume of a track with automation all at once

VCA tracks are another option - by assigning a track or group of tracks to a VCA, you can then quickly turn up or down the volume of track(s) assigned to that VCA. You can also automate a VCA by right-clicking on it to bring it up in the arrange page. The advantage of VCA is that it maintains the balance between FX assigned to the original channel, (& any corresponding sends).

http://www.musictech.net/2016/07/logic-tutorial-vcas-groups-and-aux-channels/

Another quick tip for turning down the overall volume of a track automation is to zoom in on a track, then click & scroll the value up or down (with your mouse - see pic below):

I find that the quickest way to do this is to insert a gain plugin on the track in question to adjust the volume before the automation.

enio wrote:

Is there a way to change the volume of the full track and have the automation parameters also change with the same ratio that I've set them without having to change every individual volume automation section in the track?

yes.

show the automation, drag select all the points in the track (you may have to zoom-out to make selecting all the points easier), then grab one of the points and drag up or down; the other points in the track will move along with the one you drag.