To be honest mate, I wouldn't hold your breathe for that to happen. RW have moved on. In reality, Cajon was really just included as a consolation to the US railfans after the demise of MSTSX or what ever it was going to be called (no idea what happened to the Cascade Games Foundry that were looking at picking it up, but that is another story). To revisit this would break everything - any users individual tweaking, all official and personal scenerios etc - it would just not be worth the pain.
I guess you just have to look at it as an interpretation not an exact copy and enjoy it for what it is. In any of the routes there have had to be allowances made within the parameters of the program

from Down Under
G