How to create or add bus wires to small layout?

[doctorwayne]

I have a small N scale layout that is about 3’ wide by 6’ long. It consists basically of two loops with sidings. However, I have only one set of wires going to one of its loops from my transformer and two sets going to the other loop. As a result, the layout often has problems with not enough current reaching all of its sections. To get around this, I keep having to re-solder track joints....

If you've soldered the rail joints, there should be no need for a bus wire of any type, especially on a layout that small.  Not counting staging yards and double track, nor industrial sidings, I'm running roughly 300' of mainline track using two wires soldered to the rails, as seen...HERE.
I often use multiple locomotives on trains, due to the many grades and curves (often occurring in the same places), and have run over a dozen locomotives at a time, with no noticeable degradation in their performance.

It sounds to me as if your rail joiner soldering is perhaps not yet complete...one poor or missed connection can louse-up everything.

Wayne