https://greenbuildingnews.com/2010/08/31/green-bay-open-bids-building-zippin-pippin-roller-coasters-wood-frame/
Green Bay to open bids for building Zippin Pippin roller coasters wood frame - Green Building News
Aug 31, 2010 - Now that work on the Zippin Pippins concrete foundation is under way, its time to pick a contractor to build the roller coasters huge wooden frame.
green bayzippin pippinroller coasterswood frameopen