In 1982, the MIGN assumed operation of the former Chesapeake and Ohio Railway from Grawn to Williamsburg and from Charlevoix to Petoskey, and the former Ann Arbor Railroad from Alma to Frankfort.
The DM switched cars onto the SS Chief Wawatam, a railroad ferry that provided service across the Straits of Mackinac from Mackinaw City to St. Ignace.
The MIGN was contracted to operate from Grawn to Williamsburg via connection with the Walton Junction Branch in Traverse City and from Charelvoix to its existing route in Petoskey.
Additionally, on October 1, 1982, the MIGN assumed operations of the former Ann Arbor Railroad main line from Alma to Frankfort.
Following Penn Central's departure from ferry services and unsuccessful attempts to operate regular excursion trains, the MIGN abandoned the railroad line from Pellston to Mackinaw City.