So there's no "special" import function in Trainz Classics then?
The technique you mention has been around for an age, and I've used it many times over the years (like when I beta tested the Marias Pass version of Trainz, I used this method to install it into my other versions of Trainz, and that was years ago).
What I'm talking about is the ability to import JUST the invisible bogey, so that the original poster doesn't have to move everything over from TRS if he doesn't want to.
Just moving Ja files over and forcing Trainz to rebuild it's database by deleting the assets.tdx file is going to import everything in that Ja file, which isn't what I was talking about.
So, to the original poster, if you are using Trainz Classics, and you don't mind installing everything from TRS2004 or TRS2006, then use the usual technique of moving content between installations that Ahsan has mentioned above.
If, like me, you'd rather not have all that baggage carried over, then I would suggest downloading one of the invisible bogeys off the DS, and referencing it in the config.txt file of the Class 08 loco.
If you're not sure how to do that, let me know, but I'll need to know what version of Trainz you're using.
It's definitely worth all this effort for an 08 loco.
They still go past my house, and I saw one as recently as last week.
Smiley.