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.
Bus
In parallel to the development of the bus was the invention of the electric trolleybus, typically fed through trolley poles by overhead wires. The Siemens brothers, William in England and Ernst Werner in Germany, collaborated on the development of the trolleybus concept. Sir William first proposed the idea in an article to the "Journal of the Society of Arts" in 1881 as an "...arrangement by which an ordinary omnibus...would have a suspender thrown at intervals from one side of the street to the other, and two wires hanging from these suspenders; allowing contact rollers to run on these two wires, the current could be conveyed to the tram-car, and back again to the dynamo machine at the station, without the necessity of running upon rails at all."