This is the 12872nd most frequent Korean word.
도시철도
Urban railway.
In this sentence, "도시철도" refers to the general system of urban rail transportation in Seoul, emphasizing its efficiency.
서울의 도시철도 시스템은 매우 효율적입니다.
Seoul's urban rail system is very efficient.
Here, "도시철도" is used to specify the act of using the urban rail service as a commuting tool.
도시철도를 타면 출퇴근 시간이 단축됩니다.
Riding the urban rail reduces commute times.
The term "도시철도" is used to highlight the absence of urban rail services, which affects the area's transportation convenience.