The U-33B and U-33C are Athearn's answer to the need for HOrsepower in April 1972, when these U-boats were new. The U33-C saw 375 1:1 copies produced by General Electric between 1968 and 1975. The dozen buyers of U33-C included: ATSF, BN, D&H, Erie-Lackawanna, GN, Illinois Central, NP, Penn Central, S.J. Groves & Sons Construction, Milwaukee, Southern, and SP. Southern Pacific was the major majority owner with 212 of the 375 built. With ample roadnames to pick from, there are no fantasy paints among the three Athearn U33-C roadnames. However, Athearn's inclusion of the nose headlight on its U33-C would make it accurate for only the Southern Pacific of the roadnames produced. Though the nose light works for an Espee U33-C, you'd then be missing the roof mounted light addition.

All of the Athearn '70s U-boats, U28-U30-U33, feature wider than prototype hoods. This was done to accomidate the drive motors used at the time. The boats were issued with metal trucks, though plastic truck sideframes and new drives would be standard by the 1980s. The U33-C shell includes a lower headlight mounted on the top of the nose.