Now that staff training has started, let's talk about these "new trains."
First off, I've seen nothing to suggest that the trains in question are actually completely new. From the evidence I've seen, it appears to me that the chassis are almost certainly recycled from the previous set and it is just everything above them that is being replaced. Again, I'm not sure of this, but that is what the circumstantial evidence is currently suggesting.
Secondly, these new fiberglass bodies seem to be modeled after later generation Arrow trains than Loch Ness Monster initially ran. That said, they don't seem like perfect replicas of any specific train but, instead, an amalgamation of elements from a number of different designs—all brought together to create some sort of new, Frankenstein-equse imitation Arrow train design.
That sounds negative, but I really don't intend for it to be read as such. In fact, it seems pretty smart to comb through the various Arrow looper train iterations and build a "greatest hits" train of sorts—featuring beneficial elements from the various different models.
So, with all that said, what is different about these new Loch Ness Monster train bodies?
- The new car bodies are very similar to those currently found on Anaconda at Kings Dominion. Gone are the flared fenders around the wheel wells (picture for reference). Instead we have a smooth, flat body around the wheel wells (example). The solid train wall at shoulder height has also been dramatically reduced in size compared to LNM's original design (example of the new size).
- That's not to say they are identical though. I'm not yet sure whether or not LNM's new train bodies have the same pair of rounded horizontal "pinstripes" down their length as can be found on many similar Arrow trains. Additionally, the metal bars around the shoulder area of the new bodies are substantially different than anything I've seen on trains of this style (they are still chrome too!).
- Perhaps the most notable changes with this new design (vs both LNM's original bodies and typical Arrow bodies) are the trains' headrests. They are much taller than normal Arrow looper trains. A good example of these "skyscraper" headrests can be found on Tennessee Tornado at Dollywood (picture).
- I know a lot of people were really hoping for some sort of restraint change, but, for better or for worse, the new bodies seem to be fitted with the same exact restraints as we've long been accustomed to.
- Unfortunately there is one other negative I have to mention here... May the orange stripe rest in peace.

Anyway, all that said, I'm really looking forward to talking to someone from Design & Engineering about these changes because, to be honest, overall, this seems like a somewhat bizarre linear alteration. With such a substantial investment, I would have expected to see some more substantive modifications to improve guest experience.
That said, I don't want to downplay the importance of these changes. Every investment into a ride this age is a huge deal and the park should be commended for it.