Watch the light in the caboose as it passes these two spots on your layout. If it dims, you have a power problem, most likely a bad connection between track sections - could be dirty/rusty pins.
Check the pins on all track sections, and use a needle-nose pliers to crimp the track at each end to make sure all connections are tight.

Make sure the track and the wheels and roller pickups on the locomotive are clean. Clean everything with Naphtha.


Larry