The operation of the JR (West) Suburban Train Series 221 belonging to the Aboshi yard began as the special rapid trains on the Kosei Line when the series first appeared; moreover, it was subsequently used in part of the operation within the line but was later abandoned with the revision of October 2006.
網干区車両が221系登場と同時に新快速での湖西線運用が、その後線内運用の一部にも使われていたが2006年10月改正で一旦撤退した。