 However, due to their less advanced age, the powered cars in trains 1-36~1-41 and all unpowered cars were saved from retirement and linked with other trains until at least 2006.Many of the cars built from 1984 to 1986 were even refurbished in 2006-2007 and were not retired until September 2014, when the final unpowered cars in 2nd generation train 1-55 were retired with the rest of train 1-55, marking the end of service life of the first generation trains.Trains 1-42~1-73 were 2nd generation trains and were introduced from 1986 to 1992.