Yes, you can.
There's a thread somewhere about copying the JA files from TRS2006 into the TC Series. I have done it with Trainz Driver as well. Since Driver doesn't have a Content Manager, your only way is to copy the JA files over.
Have a dig through the Classics section of the forum. I'm not sure, sine I never tried, if it will go into TRS2006. I don't see why it wouldn't.
Basically just copy the JA files from Driver into the corresponding TC folder. Might have to rename the JAs. Delete the asset.tdk, restart to let it rebuild the data base.
Dave.......