Suisun City fire investigators are investigating the cause of a two fires Saturday night, the origins of which were not immediately known. The department was called shortly after 10 p.m. to a homeless encampment on Railroad Avenue. Firefighters worked with Union Pacific Railroad to slow train traffic in the area as fire crews work to extinguish the fire. It took about 90 minutes to access and fully extinguish the fire, Fire Chief Just Vincent said in an email. Fire officials were unable to locate the inhabitants of the camp. The department was dispatched at 6 p.m. to a commercial structure fire at the Sunset Coin Laundry in the Sunset Shopping Center.