My loop of the track needs to be connected because of the display. So I'm very new and have no knowledge about trains and or size of motors. Let me try the extra power source and see what happens???  I am taking the weights in each of the back cars to lighten the load a bit.
I will try to video and attach what the project is. This might give you a better idea?  Thanks for the advice

Good Afternoon

I am running the Rail Chief set but needed to acquire more track for my project. I need to run two engines and their cars on the same track. Is this even possible and would you recommend attaching the power and speed control at separate ends of the total track length to give the trains enough power. Any advice please. Thank You