How far down do property lines go?

Cecil's Columns/Staff Reports
1

Cecil wrote at the end of his article:

“Oh, and also: at ten miles down the temperature will be about 750 degrees, so make sure that bar car has plenty of ice.”

With Cecil there are always these great punch lines! I love it, lol !

(I wanted to keep this separate from the other more serious thread started by Senegoid.)

2

It’s a real engineering design issue to be taken into consideration when building a gravity train to get you from, say, Paris to Moscow or Los Angeles to Sydney.

And you’d still need to get all the governments “on board” whose territories you’d be burrowing under.