Drew,
Hello & Welcome to the Forum!

I use tubular tracks, so I'll suggest the basics to deal with your problem.
First, make sure that your track connectors are clean and tight so you have a good connection between each piece of track.
Second, clean your track.  Use a green 3-M scratch pad, a rag saturated with alcohol, a cotton ball saturated with smoke fluid,  what ever you use to clean track...
Third, Clean Your Wheels and Pickups.
Fourth...
If none of the above works, add additional  terminal section(s)/track power connector(s) to those dead/low power areas from your transformer/power supply.

Happy Rails!
Dave