They were gradually retired from the late 1990s to 2020 by newer electric multiple unit trains.

South Korea had no experience of manufacturing and operating EMUs in the 1970s, when Seoul Subway Line 1 was under construction.

As a result, Japanese rolling stock companies manufactured the first Class 1000 trains in 1974.

Therefore, the first Class 1000 cars were based on Japanese electric multiple units: the electrical equipment was based on the multivoltage JNR 415 series (1500v DC or 20Kv AC at 50 or 60Hz), while the carbody was based on the JNR 301 series in use in Tokyo for Chuo-Sobu Line through-services with the TRTA Tozai Line.

From 1976, Korean rolling stock companies started manufacturing Class 1000 cars domestically, and eventually manufactured cars with different carbody designs.

Additionally, trailer cars (such as two 19XXs instead of a 18XX/19XX pair) have been irregularly placed as well.

[a] When Seoul Subway Line 1 first opened, the Class 1000 cars were arranged in six-car trains, and were expanded to eight-car trains between 1980-1981 before being expanded to 10 cars by the 1990s.

A six-car formation was numbered as following (where YY is one integer greater than XX): An eight-car formation was numbered as following (where YY is one integer greater than XX, and ZZ is one integer greater than YY): Trains 1-01~1-41 were 1st generation trains and were introduced from 1974 to 1979.

All other cars were built by Korean railcar manufacturers Daewoo Heavy Industries and Hyundai Precision under license.

All trains were assigned to Guro Depot and had the old Korean National Railroad (KNR) livery up to their retirement.

In place, 42 motor cars were manufactured in Korea between 1980 and 1981 for the seven donor trains.

The train that became train 1-02 was involved in an accident at the Hankuk University of Foreign Studies station on October 2, 1984, that led to two damaged cars (a driving car and a motor car) being scrapped and the rest of the train being placed out of service.

The train that became train 1-14 experienced a similar accident at Incheon station and received the driving car that survived from the 1984 accident to replace the one driving car that was heavily damaged.

The cars were replaced with 3rd generation Class 311000 trains and taken out of service in 2006 when they finally reached their 25-year lifespans, and were stored at the Byeongjeom Car Depot until 2011, when they were finally taken off property to be scrapped or repurposed.

As ridership increased on Line 1, trains 1-50~1-53 and 1-57~1-63 were lengthened with third generation cars from 1994 to 1997.

[3] Meanwhile, 1082 and 1182 lasted until 2006, when they were pulled from service due to structural integrity issues, stored at the Byeongjeom Car Depot until the end of 2011, and then scrapped.

Trains 1-53, 1-57, 1-63, and 1-65 were prematurely retired in 2006, because they were coupled with eight aging 1st generation cars each, so it was found to be easier to retire the trains instead of overhauling them to be fire-resistant.

They were stored at the Byeongjeom and Guro train depots and taken off property before the end of 2015.

After retirement, parts of trains 1-72 and 1-73 were used on the Yeongdong Line for testing in mid-2017 before being stored out of service again.

The cars were manufactured from 1994 to 1995 by Daewoo Heavy Industries under model "DEC-13."

The driving cars of train 1-74 were retired in May 2020 and were scrapped by November 2021.

All cars were stored out of service except for part of train 1-86, which was used at Guro Depot as a shunter.

After retirement, a handful of Class 1000 cars were either preserved or repurposed into facilities such as restaurants and pension trains.