Seoul Subway Line 4. 2004 August 25: Bugok Station is renamed Uiwang Station. 2005 January 20: 8 stations from Byeongjeom to Cheonan are opened as another southward extension. December 16: The Gyeongwon Line branch from Yongsan Station to Hoegi Station and the Jungang Line from Hoegi Station to Deokso Station open and are renamed to the separate Yongsan-Deokso Line. This service was the predecessor to the current Jungang Line. December 21: Dongmyo Station is opened. December 27: Sema and Osan College Stations are opened. 2006 June 30: Jinwi and Jije Stations are opened. July 1: Garibong Station is renamed to Gasan Digital Complex. December 15: 8 stations from Soyosan to Uijeongbu Bukbu are opened as a northward extension. A spur line to Gwangmyeong Station is created. Uijeongbu Bukbu Station is renamed to Ganeung. 2007 December 28: Deokgye Station is opened. 2008 December 15: 6 stations from Cheonan to Sinchang(Soonchunhyang Univ.) are opened as another southward extension. December 29: Siheung Station is renamed to Geumcheon-gu Office. 2010 January 21: Dangjeong Station is opened. February 26: Seodongtan Station is opened. 2015 February 3: Gyeongin Line express trains start stopping at Gaebong and Jemulpo stations. 2017 July 6: A new limited express service was launched between Yongsan and Dongincheon stations. 2019 December 30: All Gyeongbu Line express trains start stopping at Geumjeong and Sungkyunkwan University stations and are extended to Cheongnyangni. Gyeongbu Line express trains no longer stop at Gunpo station. 2021 October 30: Tangjeong station opened as an in-fill station between Asan and Baebang. Future Plans Line 1 will be extended northward from Soyosan Station to Yeoncheon Station on the Gyeongwon Line, replacing the current "Commuter Train" service operating there. Construction on this extension began in September 2014 and is expected to be completed in May 2023. Rolling stock Current Seoul Metro 1000 series Rheostat-controlled electric car (rebuilt cars) – since 1974 VVVF inverter-controlled electric car – since 1999 Korail Class 311000 First generation – since 1996 Second generation – since 2003 Third generation – since 2005 Fourth generation – since 2019 (Korail Class 312000) Korail Class 319000 (for Gwangmyeong Shuttle) – since 2006 Former Seoul Metro 1000 series Rheostat-controlled electric car (1st batch) – 1974-2002 Korail Class 1000 First generation – 1974-2004 (some non-driving cars lasted until 2014) Second generation – 1986-2017 (some non-driving cars lasted until 2019) Third generation – 1994-2020 Depots and facilities (from north to south) Majeon signal