The way I see it is that the people that drew up the plans will have worked directly from the manufacturers plans.
So, if you're an architect/planning department for Alton, you're unlikely to know massive amounts about every single kind of ride type and track type out there.
So, when drawing the plans, you will use source material, which will be the designs off the ride manufacturer. It seems silly that they would make such a change when they are essentially just doing a copy.
It still leaves open (except the support issue, but they may just be simple tubes) about five or maybe six manufacturers. Premier, Mack, Gerstlauer, Maurer and Intamin all use very similar bi-rail track. However, only Mack and Premier have it with such thin and regular supports (Gerstlauer and Intamin using box section track in preference).
Of course, Alton could have said that they could only have bi-rail and no box, so support and track design fits with it.
It's one of those things though. You look at Blue Fire, and it looks like an Intamin (from a distance). This looks in the same way like Premier. You just recognise the way the track is supported, the track type, the way it bends and is generally designed.
However, as with Blue Fire, that doesn't always mean you're right - especially not at a distance.
I know it looks like I'm flip-flopping on this one. It's because I am. It's not possible to really 100% say which manufacturer, but you can just get a good feel. If you'd seen those plans but didn't know who made Rita, you'd have a damn good idea from the plans. That's what I'm trying to say, you can make a pretty good educated guess, but a guess is all it is at the moment.