Lou
Hello & Welcome to the Forum!

Not sure of how much track you have, so we'll go basic(KISS) with a 72 in. radius circle of track.
You have one 'lock on' at the 6 o'clock position of the circle, when your locomotive reaches the 12 o'clock position on the circle of track it slows due to power loss.
You  place an additional 'lock on' at the 12 o'clock position on the track and the locomotive no longer looses power.
Simple, 2 wires to each 'lock on', 4 wires total hooked to your power supply.......
Runs well, so you decide to a 20 ft. of straight track to each side  and you get power problems again....
so you add another 'lock on' to the 3 & 9 o'clock positions, hook up wires and successfully run your train.
But.....
Now you've got a bunch of wires trying to be attached to your transformer.
Here's where the power buss comes in, you take the 8(4 pairs) wires and insert them into one side of the buss, then run 2 wires to your transformer from the buss supplying power to all. 

I hope this helps.

Happy Rails!
Dave