Scottish inventor George Bennie had a dream. Where trains couldn't link destinations separated by water, grand railways would stretch through the skies, guiding propeller-powered planes from city to city.
Technically, the Bennie Railplane isn't actually a monorail; to the contrary, it requires both a top and bottom rail to guide its propeller-powered planes. But like a monorail, the Railplane was meant to be a transit system deliberately separated from the ground-based one. Feeling that carrying freight and passengers along the same rails was inefficient, Bennie proposed these suspended rails that would carry passenger-only planes. He also thought it would be a brilliant way to carry passengers across the English Channel, making commutes from London to Paris fast and easy.
Bennie constructed a protype rail in Milngavie near Glasgow, in 1930. The 130-yard track wasn't long enough to allow the Railplane to achieve its optimal speed of 150 miles per hour, instead only allowing for 50 miles per hour. Despite this, the track was met with much acclaim, and Bennie, who financed the original track himself, hoped to secure funding for a larger project. Unfortunately, Bennie went bankrupt in 1937, and his Railplane dreams were shattered. The track was scrapped in 1956, a year before Bennie's death.