A handsome aerial “birds-eye” rendering of a proposed elevated rapid transit system linking Detroit with Royal Oak, Birmingham, Pontiac and Rochester (as well as the Ford Motor Company plant and blast furnaces). The system was first proposed in 1915, with a working scale model presented to the Detroit city council (photo). 

But by 1922, the company was still searching for land on which to erect one mile of test track for their unusual proprietary track system, which had both upper and lower guide rails (diagram). As we now now, the system was never constructed, although streetcars ran in the Motor City until 1956.

Source: Detroitography