The osprey issue is difficult. The spot is appealing to them for a multitude of reasons- namely the altitude, and proximity to food. The lagoon is full of some sort of carp or other pest/algae eating fish to keep the lagoon mostly clean, so they can't remove the food source. They can't remove the top hat either, so it's a real catch-22 they're in.
If they have to go up there everyday to remove nest materials anyway, I don't see why they just don't cover the track with something that makes that perch uninviting to them. Remove it when it's time to test, then cover it back up. And when there's a train going by every ~60 seconds, the osprey will be a thing of the past.