У тебя красивые глаза

in a sense of possession of certain personal qualities есть isn't used, this phrase into English may as well be translated as 'Your eyes are beautiful' which if you reverse translate it into Russian as 'Твои глаза красивы(е)' won't sound too Russian or the meaning will shift to the beauty of the eyes and not to the fact that a person has beautiful eyes
because the eyes are not really what you possess they're part of your physical self and you cannot not possess them


У Вас есть ресторан на этом поезде?

and to the contrary when it's about a subject detached from a person which in other circumstances the person may not have есть is due