The "redeveloped" Super 7 Series line initially served as a rebuilding program by GE targeting Shortline and Reigional railroads that had U-boat's that needed to be rehabbed. The Super 7 was the most cost effective alternative.    

were reliable, their warranties weren't very suitable; thus the locomotives were deemed to become no longer relaible after quite some time (unlike most EMD diesel locomotives) and weren't guaranteed to last nearly as long as their competitors; but to rather service as "conventional power" to serve railroads with locomotives which would "get the job done" at any rate. 

Only one US-based customer ordered a small fleet of 17 four-axle Super 7-23B (or B23-7R; "R" for "rebuild") units, most which have since survived on various shortlines, primarily on the Providence And Worcester Railroad long after the railroad's purchase from Conrail in 1993-1994.