I hope this help you in your search. Using Returns from Regular Army Regiments, I was unable to find when your gfather came into the 10tn, but found his name in the losses (Discharge) section dated Feb 1891. His Company was stationed Fort Apache; AT during his enlistment. The 10th didn't move Montana until April 1892. When your gfather traveled to fort is was probably by train. As for further research, I would request his service record from the National Archives.

http://www.archives.gov/veterans/military-service-records/pr...

As a Keyer for the Buffalo Soldier, I have learned so about these brave men and that that are the truly America unsung heroes.

Let me know if I can help you further, Don