After the EA, EB, E1 and E2 series built from 1937, EMC went one step further when they introduced the E3 and E4 in 1938. They still had two A1A trucks with a non-powered axle in the middle and used two engines with one generator each. Instead of the Winton engines with a total of 1,800 hp, these used the new 567 series engines built by EMC themselves with a total of 2,000 hp. The E3 and E4 were built at the same time and only differed in details. Also the E5 and E6 were very similar, although the E5 was exclusively built for the Burlington Route and originally was to be styled like the Zephyr streamliner trains. In the end, all types from the E3 to the E6 still had the slant nose.

All were built as A- and B units, although most orders were for the A units. While the E3 to E5 only reached a total of 54, the E6 could reach 91 A units and 26 B units. Although the E7 was technically still similar, it featured the new bulldog nose and became very successful. EMD could sell 428 E7A and 82 E7B. The E8 introduced in 1949 featured a total power of 2,250 hp and until 1954, one sold 421 E8A and 39 E8B. The E9 increased the total output to 2,400 hp, but when production was completed after ten years in 1964, only 100 A-units and 44 B-units had been built.