I can add an interesting side note to this..
The Bay City Branch actually was abandon from Yates North. (except for the small sections already noted) It ran up to the spur that serviced Lombardi Foods (I worked there from 1985 -1991 when we were bought out by Leone Foods out of Livonia) Lombardi used to get loads of bagged flour and some can loads until about 1984. From my understanding, a lot of their cars keeped getting shipped to Utica, NY and management got tired of this mishap and switched to all trucks. They were planning on just burying their track behind the building and convert the rail docks into truck docks. I live in Lapeer, and it just so happened right at that time, we needed some track in Lapeer to put behind the GTW depot (the one Amtrak uses and is now owned by the City Of lapeer) to put some Cabooses on display that were donated to the city. (GTW 75007 is privately owned) So, I asked the president of Lombardi Foods, (Go Big or Go Home Right?) would he consider donating the track to Lapeer instead of covering them up? He said yes. So I rounded up a group of volunteers and we removed the siding and hauled it to Lapeer. Lombardi Foods even let us use one of their semi's to haul it in!
So now you all know the rest of the story of the "Caboose Track" in Lapeer..... Good Day!