9v Regulator Power Question, 1 enough or multiple?
It is never a good idea to electrically connect two regulators to the same piece of track. You could damage both of them!
I assume you are referring to voltage drop (and thus reduced power when the loco is a long way from the regulator input.
The problem is due to the fact that the electricity is carried through steel which has a higher electrical resistance than copper.
The best solution is to feed the power from the regulator along sufficiently thick copper wire to several points along the track.
The loco will then see very close to the regulator output voltage no matter where it is on the track.
I hope this helps.