Just thought of consulting my 1997 edition of “Cinders & Smoke”, the excellent guidebook for the D&SNG. Here are a couple of quotes, on pages 37 and 38, that might help on the current freight question:
“Equipment and workers are transported regularly to the site (Tacoma Power Plant) by the D&SNG.”
Also: “A five-car spur track on the east is used to store freight for Tall Timber Resort.” (The resort is along the route.)
Dick