In the Property rule, change

A Player in a Square which is not Beige may Acquire that Square, becoming its Owner. To do so, e must spend an amount of B$ equal to X times the number of that Square, where X is equal 1 plus the number of color codes (including White) on that Square. To this purpose, the Square # Zero is considered to have a number 1 unit greater than the last Square in the World.

to

A Player in a Square which is not Beige may Acquire that Square, becoming its Owner. To do so, e must spend an amount of B$ equal to X times the number of that Square, where X is equal 1 plus the number of color codes (including White) on that Square, plus the price of any machinery installed there, as if bought new. To purposes of this rule, the Square # Zero is considered to have a number 1 unit greater than the last Square in the World.