The Mill Valley Lines is a proto-freelance N scale model railroad loosely based on Janesville, Wis. It is based on the Wisconsin & Southern Railroad (WSOR) and Union Pacific (UP) operations in the area.

The railroad models traffic from Chicago (staging) and goes through Janesville, the "hub" of the layout and continues through to Elkhorn, Delavan and points south (staging). The UP has trackage rights over that line and interchanges with the WSOR near the Janesville yard.

Most of the industries on the layout are actual customers of the railroads, but have been relocated to best fit the space. There are also a few additional industries based on my interests (ie. a brewery, because beer).