As a modder i would feel honored instead of discouraged when they included my work in the game.
I agree with you that asking would have been the right way to approach this but considering the fact that UG didn't want to reveal anything about the new project (game), i do understand UG that they didn't ask. We, as a community, should be really happy that they took the modders ideas and include them in the game!
I think you are a young modder. You work for free for happiness, they use your work to earn money, you feel honored, I feel discouraged.
Usage conter payment would be more fair trade.
If the mod and the loco in the game look the same, one reason might also be, that both are quite similar to the original
To be honest, this is nitpicking and does not lead to any resolve. But I am absolutely sure that UG did not "steal" any mod content. They increased their team on both the programming and 3D modelling front and definitely have the capacity to create their own 3D models. Also, graphics and design employees most likely already worked on the new titel shortly after the launch auf TPF, as no new models or graphics where introduced with the following patches.
I hope they do work on their own efforts. But when you don't have blueprints the mod for the same thing can't be the same, this is analyzable, based on distribution of vertices and "minor bugs".
I was a 3D + 2D modder for an formula one game about 15 years ago, I know very clearly how to find out models copied from others. I stopped modding for that game because of mod stolen.
And for copyright issue, I don't know if UG have asked CR for usage of these two logos, obviously no other logos of a living company appears in this game, and no declaration about the copyright of CR logos in the website.