Where a subdivision borders on or contains a railroad right-of-way, waterway, or major street, the plan commission may require a street approximately parallel to and on each side of the right-of-way, waterway, or major street, at a distance suitable for the appropriate use of the intervening land. The distance shall be determined with due regard also for the requirements of approach grades and future grade separations.
('69 Code, App. B, § 6.9)