▁and ▁Nam si , ▁leading ▁Sent ets u ▁to ▁national ise ▁the ▁S inu iju — N am si ▁line ▁on ▁ 1 ▁April ▁ 1 9 4 3 , ▁naming ▁it ▁the ▁Yang si ▁Line . ▁South ▁S inu iju ▁Inter lock ing ▁was ▁elev ated ▁to ▁station ▁status ▁on ▁ 1 6 ▁October ▁ 1 9 4 3 . ▁ ▁Between ▁ 1 9 1 7 ▁and ▁ 1 9 2 5 , ▁the ▁management ▁of ▁Sent ets u ▁was ▁transferred ▁to ▁the ▁South ▁Man ch uria ▁Railway , ▁during ▁this ▁time , ▁Sent ets u ▁was ▁referred ▁to ▁as ▁" M ant ets u ▁G ye ong se ong ▁Bureau "; ▁however , ▁on ▁ 1 ▁April ▁ 1 9 2 5 ▁management ▁of ▁rail ways ▁in ▁Korea ▁was ▁returned ▁to ▁the ▁Railway ▁Bureau , ▁and ▁Sent ets u ▁became ▁independent ▁once ▁again . ▁Pass enger ▁service ▁was ▁expanded ▁in ▁the ▁ 1 9 3 0 s , ▁seeing ▁the ▁introduction ▁of ▁the ▁" H ik ari " ▁limited ▁express ▁running ▁from ▁Bus an ▁to ▁X in j ing , ▁Man ch u ku o , ▁in ▁November ▁ 1 9 3 4 ; ▁then , ▁in ▁November ▁ 1 9 3 9 , ▁the ▁North ▁China ▁Transport ation ▁Company , ▁in ▁conj unction ▁with ▁Sent ets u ▁and ▁Mant ets u , ▁introduced ▁the ▁" K oa " ▁and ▁" T ai ri ku " ▁limited ▁express ▁trains , ▁running ▁between ▁P us an ▁and ▁Be ij ing .