Double-decker bus
The first commercial horse-drawn double-decker omnibuses were introduced in England in 1847 by Adams & Co. of Fairfield, Bow, then improved upon by John Greenwood, who introduced a new double-decker in 1852.
Twin Coach
Twin Coach was an American vehicle manufacturing company from 1927 to 1955, based in Kent, Ohio, and a maker of marine engines and airplane parts until the 1960s. It was formed by brothers Frank and William Fageol when they left the Fageol Motor Company in 1927. They established the company in Kent to manufacture and sell buses with a new concept design. The body structure of this new bus was unique in that the body also became the frame and two engines – "twin" engines – were used to allow for larger passenger loads. This concept was patented by William B. Fageol.