 All new trains are ten cars long; six additional cars were built to lengthen second generation trains 1-59~1-61 from four to six cars for Ansan Line service.All of train 1-74 sans the driving cars (made excessive when 2nd generation train 1-62 was retired) and the additional cars for trains 1-59~1-61 were retired between 2015 and 2016.Two powered cars from train 1-79 were retired in March 2019 because of mechanical issues; as a result, two 2nd generation powered cars were temporarily brought back into service to replace those cars.