GE U18B Discussion

Typewriters wrote:It's perhaps even more interesting simply from a theoretical standpoint to consider the reliability of these U18B's considering that their 7FDL-8 engines have, unlike 7FDL-12 and 7FDL-16 engines, gear driven counterbalance shafts in their crankcases to balance forces on the crankshaft. This design feature is perhaps best known to railfans for having been used in the 8-251F that ALCO used in the C-415, but the eight cylinder Cooper-Bessemer / GE engine of model series FVBL-8-T and all submodels of 7FDL-8 have had similar counterbalance shafts as well.

GE must have known something that Alco didn't know, in order to get higher reliability from a similar configuration. Any speculation on what that might be?

I couldn't say -- but it does seem that ALCO didn't have an eight cylinder engine until the design that was used for the Navy and for the C-415, so that the Cooper-Bessemer / GE design was a number of years older and more widely produced, meaning more time to get information back from the field and make design corrections. Just a rough guess is that the C-B / GE design was made about / at least a decade before the ALCO design.... without pulling all the books out!

-Will Davis

That seems like a plausible and likely explanation. Thanks!

MEC 400 & 406 in northern Maine, 1991:

Video by "fmnut": https://www.youtube.com/watch?v=BMFdYoV2flY" onclick="window.open(this.href);return false;

Thanks to railroad.net member "690" for the link!