Sun Tran busses are not posted, and they do not have secure storage. Therefore, they do not ban open or concealed carry.
I ride occasionally with my bicycle, to pick up or drop off a vehicle for service. I always open carry, and no one has said boo to me. Frequently ride the bike with a shoulder rig on...
Last trip I asked the driver. He said that Sun Tran leaves it up to the driver if a person looks dangerous, to refuse the ride.
Haven't tried bringing the rifle on the bus yet.....
Anyhoo, my .02 worth..