You don't have to visit Caliafornia. You can do it via internet. Did he receive a railroad retirement pension. You can go right to the Railroad retirement Board and get your info.
They even have a geneology department; but since he worked for the Railroad. That would not be necessary. You could go via internet or an 800 number. I looked them up on the internet; but I know I could not get that info unless I was a relative. You could go to (1.) USRA United States Railway Administration (2.) Railroad Timeline and go to U. S. Railroad Retirement Records and also Railroad Records. (3.)Union Pacific Railroad.
I know they won't give me any ibnfo.; but you could get it probably. He went from Fireman to engineer and it probably didn't happen overnight. So ther has to be records there. I sure wish you would let me know what you have found. I would like to know the outcome.