Compared with passenger locomotives made later by EMD, the noses of the E3, E4, E5, and E6 cab units had pronounced slants when viewed from the side.

The Chicago, Rock Island and Pacific owned an equally interesting pair of similar power cars known as the EMC AB6, which were mechanically identical but had boxcabs in blunt noses.

Three E6 locomotives survive today: Atlantic Coast Line E3A 501 was wrecked before delivery, returned to EMC and rebuilt as an E6A.

After retirement from regular service, the unit was restored to purple & silver colors and run on Midwest fan trips by owner Glenn Monhart.

Chicago, Rock Island & Pacific Railroad E6A #630, was operated by the Midland Railway, in Baldwin City, Kansas.