Good to hear that you have identified the power feed problem that was dropping the voltage on sections of track.
Regarding the "over powering" approach, I have noted that voltage drops on transformer output as the load (amps) goes up on non-regulated power output (i.e. isolation transformers). Before I migrated to PowerHouses, I was using Hammond "filament" transformers to provide 18 VAC to my TPCs. Hammond part numbers 165S18 (10A output), 165U18 (15A), and 165V18 (20A) are appropriate. These are step-down isolation transformers and I used a 360 watt Variac upstream of the Variac to trim output voltage to 18v. I noted as loads were added to the loop(s), the voltage needed to be trimmed up. During sessions using a single 20A transformer driving two 10A outputs to two TPCs, I noted reduced voltage during conventional operations. I ended up using discrete 15A or 20A transformers for each TPC/loop. Airpax 10A instant trip breakers limit track current, but the over-capacity of the power supplies kept voltage close to the desired 18v on loads up to 10A.
Because I'm not running high amp Pullmor locos these days, the PowerHouses suffice for power. They are 1/3 the weight and size of my Hammond boat anchors in their steel enclosures and include overcurrent protection.
