Same. I'm on a small neighborhood in Burlington's New North End near Ethan Allen Park, and we've got all utility lines buried. But that was easier to do since this section wasn't expanded/built in until the late 1960's. Much easier and cheaper to do at the time of than to retrofit (though still more expensive than regular lines.)

FYI, that's too much of a drop. The max. slope for a zipline is 3' of vertical per 100' of horizontal with no brake, and 6' of vertical if you are using a proper brake:
https://www.ziplinegear.com/pages/how-to-build-a-zip-line-section-one-concepts#:~:text=ZIP%20LINE%20MUST%20NEVER%20EXCEED,MAY%20CAUSE%20INJURY%20OR%20DEATH.

Please do not make a death trap zipline that drops 25' over only 225 feet of vertical.