Cool find - here is some info...
Michigan United Railway: Another of Michigan's large interurban systems, the Michigan United began operations in 1906 through the formation of several smaller lines and served Lansing, Battle Creek, Owosso, Kalamazoo, Jackson, Flint, and Saginaw. It was also another of the state's well engineered lines providing high speed service with heavyweight equipment. The company was even profitable enough to purchase the Michigan Central's former main line (a standard railroad) between Kalamazoo and Mattawan when the company realigned its route. In 1911 the Michigan United leased a small standard railroad, the Kalamazoo Lake Shore & Chicago Traction, which was abandoned by 1925 due to lack of profits. Prior to this the company had also acquired another small line, the Grand Rapids, Holland & Chicago Railway. By 1923 the MU was in financial trouble and was reorganized as the Michigan Electric Railway. Profits continued to decline through the 1920s and service was finally abandoned by 1929.