I noticed a little while back the 4-8-4's were going dcc, i wasn't a Santa Fe fan back then, but i am now. It saddened me to notice there was no 3751 as a number choice, why is that bachmann?

My guess someone has the license rights to that number.  Possibly the crew in San Berdo who restored it?

Bachmann's locomotive is not the same class as the 3751 class.   There is a big difference.

O, your right. It looks awful familiar. O well, i guess I'll buy some other number loco. I wonder if b-mann knows the number northerns he does make are in two different classes. We got the 3765 class between numbers 3765-3775 and the 3776 class between numbers  3776-3785. So some of the classes are different anyway, and seem to me the engine body doesn't look like either class, hope this helps. 

Just in case b-mann wants to know the specs of the classes  http://steamlocomotive.com/northern/atsf.shtml