The old Fond du Lac depot was built in the late 1800's. Now it houses the newest music venue in town, The Passenger Lounge.The Fond du Lac depot last saw trains in the early 1970's. Since that time, the space has mostly sat unused.The new owner Mike Peterson says his plan was set in motion while he was talking with people at a music venue in Elkhart Lake."One of the gentlemen I was speaking with introduced me to the previous owner," Peterson sai…