This is the 6492nd most frequent Korean word.
역을
"역을" means "station" or "role" depending on context, as it is a form of the word "역" with a grammatical particle.
In this sentence, '역을' functions as the object of the verb '지나면' (to pass). It is used to refer to a train station as the direct object of the action.
다음 역을 지나면 목적지에 도착합니다.
After passing the next station, you will reach your destination.
Here, '역을' again acts as the direct object, now for the action '걸어서 둘러보았습니다' (walked around). This indicates the station and its surroundings that the speaker explored.
이번 여행에서는 역을 걸어서 둘러보았습니다.
In this trip, I walked around the area of the station.
In this case, '역을' is used as the object of '건설 중' (under construction). It denotes the new station that is being built.