In the United States, the tender was common practice from the outset. At first, a flatcar was mounted with water barrels and a wood crib (and sometimes stacks of hay bales to "protect" passengers from engine sparks)—but gradually, they assumed their unique functionality and design. The first eight-wheeled tender (with a bogie under each end) was built in 1838 and, though wildly successful in the United States, was only adopted by the rest of the world after 1860.