 Ten additional cars were built to lengthen first generation trains 1-39~1-41 to ten cars.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.As this rearrangement occurred, trains 1-50~1-53 and 1-59~1-61 were lengthened to ten cars, and trains 1-57~1-58 and 1-62~1-63 were lengthened to six cars for Ansan Line service.