This is the 14 Series 15 model, an essential model for the Sanyo Main Line Blue Trains between Kansai and Kyushu.
From the 20 Series to the 14 Series, 24 Series 24, 24 Series 25, and this model, the lineage of JNR-era Blue Train vehicles is now complete.
The sleeper express "Akatsuki" began operation with the timetable revision on October 1, 1965, and is known as the ancestor of the overnight express trains (Kansai Blue Trains) connecting the Keihanshin and Kyushu regions. It is the last surviving train.