It was originally called the Tuscola and Saginaw Bay Railway (reporting mark TSBY), which was formed on August 26, 1977, to operate over former Penn Central lines from Millington to Munger, and from Vassar to Colling.

[3] MDOT transferred the remainder of the ex-Ann Arbor main line from the Michigan Northern Railway to the TSBY in May 1984.

[3][6] The Huron and Eastern Railway replaced TSBY as the designated operator on its original three lines around Vassar in 1991.

At the same time, the TSBY sold the 9.5 miles (15.3 km) of the Saginaw branch between Richville and Harger to the Huron and Eastern.

The GLC also operates a small portion of the abandoned CSX Ludington Subdivision in Clare, to serve a local plastics factory.