The fall of 1971 brings Athearn's General Electric U28-B and U28-C models. The General Electric prototype saw 71 orders between December, 1965 and December, 1966. Original owners included: CB&Q, L&N, NP, Pennsy, SP, and UP. Athearn introduces the U28-C in a group of GE boats that included the U28, U30, and U33 in both B- and C-truck examples. Only three roadnames were included in the release of the U28-C and these would remain the only offerings for this model, until the 1990s. Athearn includes a nose headlight on all the U-boats introduced in the '70s. This headlight makes the U28-C prototype for only the SP or the three roads Athearn offered. The U28-C was included in the Athearn made Cox line of 1971-1975 in both the UP and PC versions. Metal trucks were standard for this model, until retooling to plastic in the '80s. All of the Athearn U-boats of the early '70s suffer from wider than prototype hoods to allow for the drive motors of the day. The boats all include non-prototypical lugs on the shell frame at each end of the fuel tank area to snap the shell onto the drive. This Athearn design would not be corrected until the '80s and the GP38-2 and GP50 releases.

The big spotting feature differences between the three Athearn U-boats, whether B- or C-truck examples, is found on the rear of the units. Illustrated is the rear of the U28-C. Notice the width at the tail end of the long hood matches that of the area directly behind the cab. The U30 has a wider end, this is the radiator section of the long hood. The U33's radiator section is even wider or more pronounced, than the U30 and U28.

As was the design of the day, the grab irons are cast on this diesel and the pilot has a slot cut out of the lower middle to allow the underframe with coupler installed to snap into the shell. Separate parts for this and the other Athearn U-boats included the brake wheel on the nose, bell with housing and horn on the roof behind the cab, cab windows and numberboard and headlights clear material and handrails. The body shell is a single piece with the cab area being separate.