Just for the record.
Animas Forks is roughly 4 miles uphill from Eureka. It is at an elevation of 11080 feet. Eureka is at 9875 feet. That translates to a difference of 1295 feet in elevation in 4 miles or323.75 feet per mile. That is an average grade of greater than 6%. If you are operating any trains on 6% grades, you need a lot of power to move a very small load.
As far as the pusher goes, both SG&N #34 and SN #3 were built with capped stacks, but the one on #3 was significantly taller, almost out of proportion with the locomotive. Adding that to the location of the turbogenerator, and the pusher almost has to be SN #3.