From the Wikipedia page 
The Washington State History Museum, in downtown Tacoma, Washington, is one of two museums owned and operated by the Washington State Historical Society under the official approval of the Washington State Legislature, the other being the Capitol Museum.
The museum maintains three permanent exhibits. One is about the history of Washington State and relation to the Pacific Northwest with artifacts from Women's Suffrage, Industrialization, Native American Tribes and items such as Clovis Points.
The top floor of the museum contains the History Lab, where visitors can explore and learn about history in a more hands-on fashion with multiple interactive exhibits.
Also on the top floor is the permanent model train layout, said to be the largest in the state at 1,700 sq ft (160 m2), which recreates scenes from Tacoma's Union Station (where the museum is located) and other regional railroads. The museum has an annual Model Train Festival in December.
The website is .