The Haffner Thrall flatcars were originally purchased by Ringling / Barnum to carry two of the seat wagons. Structurally, that didn't work out very well. After RBBB came of the road from under canvas in 1956, they sold them off to Royal American Shows. When Royal American came off of rails, they offered them for sale. The Circus World Museum bought 6 of them for the Great Circus Parade train. Two of them were actually refurbished and used. The other four are still beside the train sheds at CWM.