In DCC terms a consist is when you link two locos together - each having different addresses - so that they operate as one. The grades on my layout are quite steep and each of the two GP-15s can manage abut 5 cars without struggling. I put together a train with 13 cars with on GP-15 at the head and one in the middle to see what happened. I did it really because I have never been able to run such a train before on any layout I have built over the years.
Making the consist was easy with my ZTC controller. I then took a video of it all. This was put into iMovie for editing. I found a public domain sound track of a freight train and had an interesting (!) time adding that to the video.
This is the result.