NS C39-8

I understand all NS C39-8 and C39-8E has been retired. Is there any significant difference between C39-8E and C40-8? Seems like there are some negative comments regarding C39-8 from a few people, anybody know why that is the case?

I ***think*** (my memory was always fallible and isn't getting any better with age, and C-39-8E production was twenty-nine years ago!) that the change from C-39-8E to C-40-8 involved a new turbocharger, not just a change in the control software. But check with someone else before betting money on that!

There is one visual difference: the C39-8E had the air reservoirs in the conventional location (mount crosswise on the frame, one before and one after the fuel tank), whereas the C-40 made the change to having them mounted in an indentation on the side of the fuel tank on the right side.

Neither is a really MAJOR major difference. Given the overall similarities, however, perhaps the C-40 amounted to a refined and thoroughly debugged version of the C39-8E: maybe the C39-8E got blamed for what were in effect teething troubles for the design? (But that is sheer speculation on my part with nothing to back it up.)

It's surprising that NS didn't rebuild them. Look at all the used Chevys they got All the SD60, which were fodder for the SD60E program, and the SD90 MAC program.