Why do all that to get two locomotives to run together when you can program them to do so? The way you are trying to do this, every time you want to speed up or slow down you have to adjust both locomotives, and until you make those adjustments they will fight each other. Can you imagine what would happen on the real railroads if the engineer had to keep running from unit to unit adjusting throttle settings? Thankfully, control of the entire consist as one locomotive dates to the early days of diesels. With speed matching we can do the same on our model trains.