It should be "When will the train station be renovated?" In English, except when the question word is the subject, we place the first verb (or the auxiliary "do" if it is a simple tense) before the subject. For example: "Why are you reading that book?" "What countries have you visited?" "Where do you study?" (simple tense) "Who was using this?" ("Who" is subject)

When will the train station be renovated?- Correct