Sammie,
Dayton is the railroad station name for a dry sort yard and mill that debarks, bucks and re-saws logs into rough lumber. It's about 11 miles west from Shelton, at the end of railroad track into the Olympic peninsula woods. At Dayton mill, logs are rough cut into dimension lumber and then railed to the drying and planing mills in Shelton.
In early 2011, Simpson RR had been sporadically shut down. In July, Simpson began using their RR again to haul Canadian timber barged into Shelton to feed the Dayton mill. Dry sort seems to be a misnomer - those logs were waterlogged and pretty crusty with barnacles.
Coincident with SP 4449 visiting Tacoma and Easton WA in late July 2011, I visited the Simpson RR in Shelton. Simply for asking and signing a waiver of liability, my 15 year old son and I were granted the privilege of going into the Shelton mill property and pleasure of riding along the railroad line in the company of the Simpson RR crews. Spent the entire workday shuttling back and forth between Shelton and Dayton with them. A fine bunch of guys, and very hospitable towards railfans. We were told that despite the repetitious routine of shuttling logs and lumber, every day on the railroad was different and exciting. At the end of the day, we helped them position the locos on an "Arm-strong" turntable at the shop, and parted as friends.
Sad to hear this operation is ended, and I hope those fine fellows find other exciting work in the railroad industry.