In 1872 the P.T. Barnum Circus had grown so large, that it was decided that they would only play at large venues, and that they would travel by train. P.T. Barnum had two of his partners, William Cameron Coup, and Dan Costello, to come up with a system to load the circus wagons on to railroad flat cars. Using a system of inclined planes, called runs, and crossover plates between cars, they developed a system ropes and pulleys, along with a snubber post to get the wagons on and off of the flat cars. They used horses to pull the wagons up the run, then would hitch a second team to pull it down the run cars (flats). It was in 1872, that when they first moved by train they used Pennsylvania Railroad flatcars. This turned out to be hazardous, since the Pennsylvania Railroad's cars were in poor shape.
It was decided in mid season that they would buy their own cars, and when the P.T. Barnum Circus left Columbus, Ohio, it was on the first circus owned train. On the train, there were sixty cars, forty-five being flatcars, carrying about one hundred wagons. The off loading was much the same as loading, but a snubber post was used to help break the wagons' descent down the run. The system that was first used in 1872, is still used today by the RBBBC although through more modern methods.
Circus trains have proven well-suited for the transportation of heavy equipment (tents, rolling wagons, vehicles and machinery) and livestock (elephants, jungle cats and horses), despite tragic accidents over the years.
Ringling Bros. and Barnum & Bailey Circuses separately and together grew to dominate live entertainment through their frequent purchases of many other American circuses. In modern times, they travel in two circus trains, the blue unit, and the red unit, following an alternating two-year schedule to bring a new show to each location once a year. The RBBB circus trains are more than a mile in length, and include living quarters for the performers and animal keepers. There are also special stock cars for the exotic animals and flatcars for the transportation of circus wagons, equipment, and even a bus used for local transportation at performance sites.
Another, the last operating carnival train in the United States, is operated in the east by Strates Shows.
Circus trains have always been enjoyed by the populace, because of their unusual nature and photogenic qualities. Railfans monitor the annual movements of circus trains quite closely.
Two famous cinema portrayals of circus trains were 1952s The Greatest Show on Earth by Cecil B. DeMille, starring Charlton Heston and 1989s Indiana Jones and the Last Crusade by Steven Spielberg, starring Harrison Ford, River Phoenix and Sean Connery.