Hi Thomas,
I was able to check British Columbia Marriage Registrations on familysearch.org and there i can see that Alfred Martinson married in Kamloops had a father called Martin Hendrickson from Ramsala Sweden. Thus he is not the Alfred Martinson from Alaska.
However in the meantime I also got the following information:
US Naturalization Record for Alfred Martininson which he initiated on 23 Feb 1910 while in Seattle, Washington before going to Alaska in 1910. Source citation: National Archives and Records Administration (NARA); Washington, D.C.; Naturalization Records of the U.S. District Court for the Western District of Washington, 1890-1957; Microfilm Serial: M1542; Microfilm Roll; 6. He listed the following information:
Name - Alfred Martinson age - 28 years
Occupation - Railroad man; Color - white; Complextion - Light; Weight - 195 pounds; Hair Color - Brown; Eyes - Blue; No visable defective marks;
Born - in Slimminge, Sweden; Born on - 11 day of December 1881; Residence - 3 Washington St., Seattle, Washington; Emigrated from - Malmo, Sweden;
Vessel - Coronia; Lived in Liverpool, England before he left Europe; Arrived in New York on 25th of October, 1905; Missed Height - 5 ft, 10 inches.
All assistance for further tracing is appreciated
Leif Mårtensson