Hello PDs,
Eddy, the Great Lakes Maritime Database lists several City Of Detroits dating back to 1866 but this is not one of them. She is not listed among the transfer ferries in the book The Great Lakes Car Ferries. She may have been a proposed plan for a ferry but never built. Judging from her open decks and low freeboard, she would have served the Detroit River/Windsor area. Her double deck would have required additional loading equipment that, to my knowledge, has never existed. All of the Detroit River car ferries became obsolete when a rail tunnel was built under the river. Looking at the model, she looks rather unwieldy even with two sets of paddles and especially with that boxy hull construction.
I think that this is more than likely somebodies fantasy rail ferry.
Randy