Spikre: I don't know about the CB&Q. "Northern Pacific Diesel Era" by Lorenz Schrenk specifically states that the NP wanted the U25 bodies for its U28Cs, so it apparently wasn't that they were in a hurry.
The book says, discussing the bids received, that the competition was the C630, which the NP refused because they didn't want Alcos, and the SD45, which the rejected because it wasn't in production yet. Then it says that "General Electric offered an improved U28C design based on the U25C. In addition, in order to reduce maintenance costs, GE offered to custom-build the units for the NP with the same body dimensions and configuration as the earlier U25C's that the road already possessed.GE had already provided similarly customized U28C's for the CB&Q." Earlier, in the U25C section, he noted that NP was impressed by the low maintenance costs of the U25C.
The author also says that NP didn't like EMD's wheel slip control, claiming it didn't work as well as GE's. Oddly, the GN preferred EMDs to GEs, judging by the numbers purchased. Obviously, even if they were owned by the same group, and planning to merge, they had very different tastes in locomotives.
