S.P.& S. Railway Historical Society [WA]
"The Spokane Portland and Seattle Railway Historical Society was founded in 1981 to preserve the history of the Spokane, Portland & Seattle Railway and disseminate information to its membership about the railway and its affiliate lines including the Oregon Trunk, the Oregon Electric, United Railways, Astoria & Columbia River, and the Gales Creek & Wilson River." The society also puts out a variety of publications throughout the year, many of which are focused on modelers, who compose a majority of society members.
The site offers an online store, current and past issues of the "The Northwest's Own Railway," the S.P.&S. publication available for purchase, and a brief history of the society.