(Portland, OR)  --  A man is facing charges after allegedly assaulting another man with a tire iron onboard a TriMet bus.  Police arrested 47-year-old Michael Henry Jr. for the incident in Aloha early Saturday morning.  Police say he was a passenger on the bus when he hit a 27-year-old Beaverton man in the head and neck with a tire iron and then fled the bus on Southwest Tualatin Valley Highway.  Police tracked him down and arrested him.  The victim was hospitalized.