Not so far ago I browsed Eurobricks and in topic named "Best Monorail" I found a photo of Monorail train from Aquazone theme, which was never released. From this what was written there, it was called "Sea-Tron Monorail" and was designed sometime around 1990. The photo is from Brickjournal magazine from summer 2009, from Mark Strafford's article "The Truth About SPACE!".
Firstly: a choise of minifigs is weird; in the lower right corner we can see proper (at least in my opinion) diver in yellow outfit, and at the station there are two red Futuron astronauts, who fit here middling. Everything else isn't bad - design characteristic for the second half of eighties, but there are some new elements: station supports, red quarter domes, yellow rings on the train, yellow Monorail motor and blue tracks supports.
We can't see here the whole set, so we can't define, does it have got long or short track, but it can be estimated, there is a bit of that. A part of tracks in the background is blue - it suggests, that the train runs on time above the water, and one time under water. It's the most similar to the first and classic Monorail set - 6990 Monorail Transport System, perhaps because they were designed thereabout the same time.
In my opinion TLG should release this set, AFOLs and younger consuments would certainly like it.