Here's a link to what's at the Fairplex in Pomona (SoCal) if you're ever in the area. Check out each of the websites for pics and more information:
www.railgiants.org - The Railway and Locomotive Historical Society, Southern California Chapter's Rail Giants Exhibit at the Los Angeles County Fairgrounds in Pomona, is a historical journey back to the glory days of the American Railroad.
www.fgrr.org - Begun in 1924, the 3500 square foot model railroad in Los Angeles is open to the public one day per month. Includes history and tour.
