I originally posted information about Antique Powerland on my website in a PLACES page on November 23, 2007 and last updated it on December 18, 2009. I am posting the railroad-related information here, with pictures and information from the 2010 Great Oregon Steam-Up. All of my information about Antique Powerland can be found at PlacesPages.
This is a former Burlington Northern Railroad Bunk Car. The number is difficult to make out entirely, but appears to be #968398. I think this car originally belonged to the Great Northern Railway. It was most likely converted from an old box car.
According to reporting marks stenciled on the frame, this flat car was previously Canadian Pacific Railway #418141.
This flat car was previously United States Navy #61-01460.
Other equipment owned by the Oregon Electric Railway Historical Society includes this spool car and speeder flatcar.