In the same year, the Tanna Tunnel opened on the Tokaido Main Line, and all express trains switched from the mountainous and detouring original route.

A 1936 trial showed a 9% reduction in air resistance when the locomotives ran with the streamlined end at the front.

As a result, the Class EF56 and EF57 locomotives reverted to boxier designs, though the post-war EF58 brought back a more streamlined look.

Following withdrawal, EF55 1 was moved to the former Chūō Railway Institute near Nishi-Kokubunji Station for apprentice training purposes.

[2] EF55 1 was designated as an important piece of railway heritage in 1978, and was subsequently restored to running condition, re-entering service in 1986 for use hauling special event trains.