The US Coast Guard 378' cutters have turbocharged FMs as main prop. The turbos are ahead of and feed the normal FM Roots blowers. Of course, when they really need the speed, they switch over to the gas turbines. I have no idea who supplied either the turbos or gas turbines.
I have seen turbocharged Detroit/GMs V-12s, (12V71 or similar model number), and I believe GM has been doing this for years with the (X)-71 series engines, and possibly others.
The EMD turbo, the GP-20 was the first (and perhaps the worst), is a whole different animal. It is gear driven at lower speeds, and operates as a free-wheeling turbo at higher speeds.