ここは一等車ではありません。

here (place physically close to the speaker, place pointed by the speaker while explaining); this place; these last (followed by a duration noun and a past sentence: time period before the present time of the speaker); these next ... (followed by a duration noun and a non past sentence: time period after the present time of the speaker); the next ...

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

first-class carriage (coach)

indicates location of action; at; in; indicates time of action; indicates means of action; cause of effect; by; and then; so; indicates continuing action; indicates certainty, emphasis, etc.

to be (usu. of inanimate objects); to exist; to live; to have; to be located; to be equipped with; to happen; to come about