The Aoimori and Iwate Galaxy Railway Lines are former sections of the Tōhoku Main Line that connected Tokyo to Aomori that were rendered obsolete for long-distance passenger services by the completion of the high-speed Tōhoku Shinkansen between Tokyo and Shin-Aomori stations.

Two-car Aoimori 703 series sets began operations on the line on the same day to handle the increased loads presented by the opening of Tsutsui Station.

The Aoimori Railway Company leases these facilities from the prefectural government and is responsible for operation of passenger trains on the tracks.

This scheme is intended to mitigate the company's burden as an owner of fixed assets and is known as "track/service separation" (上下分離方式, jōge bunri hōshiki).

[11] The Aoimori Railway operates a fleet of 701 series two-car electric multiple units (EMUs).

[13] Two new two-car Aoimori 703 series EMUs were delivered in November 2013 and introduced from the start of the 15 March 2014 timetable revision.