If Dovetail is going to have long distance trains for the NEC then they might as well make models for the appropriate consist for the trains. How difficult is it to make baggage car and viewliner cars.
It will be Possible, but time consuming and it has to weighed as to what value a baggage car or viewliner brings to us players compared to what else could and needs to be achieved in the same time frame.
Probably after dtg creates the loco that runs on another route frequently. Then they can just release it as a gameplay pack loco with the new coaches considering it's the same loco.