Last Updated: January 31, 2025
As I expect most readers of my blog to know, the Seoul Line 1 is a very complicated line with many different service patterns, which primarily consist of 6 patterns.
Local trains from northern section to Incheon
Express/Limited Express services between Yongsan and Dongincheon
Express services from northern section to Incheon (runs as local from Kwangwoon Univ. to Incheon)
Local trains from Kwangwoon Univ./Cheongnyangni to southern branch
Express trains from Kwangwoon Univ./Cheongnyangni to southern branch
Seoul Metro trains only run services 1 and 4, and even then they only run as far as Byeongjeom/Seodongtan, rather than going all the way to Cheonan or Sinchang.
So here’s where the shenanigans really begin. There are several one-off services that run only a few times a day.
(this is also known as the Green Express or Seoul Express)
This is a service that runs only during RH, only in peak direction, and only twice a day in each direction. It has the unique characteristic of running 17.3km (10.75mi) non-stop, skipping 10 stops in a row. Another unique characteristic of this service is that it uses the mainline tracks from Seoul to Suwon, rather than the dedicated metro tracks, and is actually on-par with some of the slower Intercity Mugunghwa trains in terms of speed. Sadly, this is the reason why it can only be run during RH, as there are too many trains on the mainline tracks (including freight) for this train to run during off-peak hours.
As I explained earlier, trains going to/from the southern branch (Guro - Sinchang) only run from Kwangwoon Univ. or Cheongnyangni, if you want to go between a station that is north of Kwangwoon Univ. and a station south of Guro, you have to do a transfer somewhere between Guro and Kwangwoon University.
Except… there are two trains a day, in the morning hours, that go directly from Uijeongbu to Seodongtan, for apparently no reason. Nobody knows why these trains exist, or why they are not doing this during off-peak or afternoon RH. But the existence of this service means that for twice a day, you can go from Uijeongbu to Anyang, Suwon, Uiwang, or Byeongjeom without any transfers.
Of course, how could I forget the Gwangmyeong Shittle, the infamous metro on HSR tracks? This is one of the more frequent services in this list, running once or twice an hour, depending on the time of day. Initially, the Gwangmyeong shuttle was less of a shuttle, running all the way to Yongsan with 10-car trains. However, due to its poor headway caused by the fact that it shares tracks with KTX trains, the demand was abysmal and it was eventually reduced to the 4-car service to Yeongdeungpo we know and love today.
An interesting connection between the Gwangmyeong Shuttle and the “Green Express” is that they actually share platforms at Yeongdeungpo. The Gwangmyeong Shuttle’s terminating platform just happens to be the closest to the mainline tracks, so they put some switches and stops the Green Express there.
There is currently one extension, currently test running and slated to open this December, to Yeoncheon. However, this extension’s service pattern is still undetermined. This is a list of possible service patterns.
Often dubbed “Yeoncheon Shuttle,” this was the original intended operating pattern by Korail, which faced heavy criticism from the people of Yeoncheon, as this would require a transfer at Dongducheon to go anywhere like Yangju, Uijeongbu, or Seoul.
Yeoncheon Shuttle 2, this is better in that people of Yeoncheon can go to the sprawling satellite cities of Uijeongbu and Yangju, but still fails to reach Seoul directly. Also, if this one or route 1 gets chosen, line 1 will come to possess the cursed trait of requiring a whopping two transfers to go between some points on the same “line”.
This is much better than 1 or 2 in that passengers can now go directly into Seoul, transfer directly to Seoul Metro lines 4 and 7, and now passengers can go between any two station pairs on the line 1 in only one transfer (except Gwangmyeong, but we don’t talk about that station). However, it’s still pretty bad in that passengers can’t go directly to downtown Seoul, as the trains still won’t go into core line 1.
Unfortunately, the trains that Korail ordered for the Yeoncheon extension do not have DC capability, so they cannot go into core line 1. This was proposed as a way for these trains to go into Seoul without going into core line 1, as the GJ line is entirely AC, and there is a junction at Cheongnyangni allowing trains to go from the GJ towards Uijeongbu. This could work, but it’s questionable. The GJ line section from Yongsan to Cheongnyangni isn’t as busy as the section from Cheongnyangni to Sangbong, but it still isn’t very easy to run more trains here. Not to mention, all the complications of a service pattern that runs on multiple established lines, whether to show this as line 1 or GJ on the line map, plus the complications of running passenger service on a single track connecting track that hasn’t seen passenger service since early 2000s.
There is also the simpler idea of just running main services to Yeoncheon. Although the trains that Korail ordered for this extension are 6 cars long, the platforms and PSDs of this extension are still 10 cars long, so 10-car mainline trains should have no trouble running on this extension. This could come either as a pure extension, with no shuttle trains, or a mix of main services and shuttles operating any one of the above possibilities 1~4. This is the best-case scenario for Yeoncheon Residents, as it would mean that they can go to downtown Seoul as well as all the way to Incheon with no transfers, and anywhere south of Guro with just one transfer.
Korail ended up running main services to Yeoncheon. You can now take direct trains from Incheon, through downtown Seoul, all the way north to Yeoncheon. The shuttle trains that Korail had ordered (with no DC capability) ended up being yoinked by the Suin-Bundang Line because they are not needed on the Line 1.