An interesting post by Mike Bumbeck at the HMN blog, telling all about the Goodyear blimps and pair of control gondolas that are on display at the Smithsonian. The Model AA panel truck that guides the Pilgrim is quite interesting also. Photo courtesy of the Goodyear Tire and Rubber Company.
Dan Strohl has put together a great post on a spindizzies or tethered cars, with quite a bit of history and information including an interesting video. The photo above shows the non-tethered version that stayed on the track being guided by the vertical strip you can see on the track.