What you can do is create a "New Folder" in the loco file ... put a "Notepad Text" file in that "New Folder" ... copy paste the original cab kuid in the notepad text file ... change the cab kuid (in 2 places in the config file) to another cab kuid numeral ... If the cab doesn't work well, copy paste the original cab kuid numeral from the "New Folder", back into the config file, overwriting the experimental cab kuids.
Creating a "New Folder", inside an assets folder, is an excellent way to temporarily hide a flie from Trainz (yet it is still there in the assets folder)... so you can easily bring it back, if things don't pan out well.
Or experiment on a Clone of the loco.