It’s taken about a week to have more to report, as will become clear. It turned out I did have a 25 foot or so length of one mainline with unusually bad voltage drop, finally realized that when I ran the same train on the other main parallel to it. We used some inappropriately “a bit too aggressive” flux that required cleaning (not possible inside a rail) soldering track pins, that caused corrosion at the joints, for the most part just a little unsightly but in that one stretch the electrical continuity through the GarGraves rail joints appears to be nearly zilch. The voltage drop reflected nothing conducting much except for the 12 ga bus wires with their few connections along the way adding slight resistance in that stretch, causing a maximum of 4 volts drop for those 4 Pullmor motors in the F3 set. No wonder the stalling. Spent a few days as time and neck and back permitted making and installing a wire harness under the layout to add a second pair of 12 ga bus wires tied to the existing ones every 6 ft or so to prevent any DCS signal reflectance problems, and adding a few more drops to the rails as well. Now less than half a volt drop at farthest point from feed to the bus wires. That helped tremendously with the behavior of the locos.
However still some issue with speed variation and inability to run a slow freight at constant track voltage without stalling. So proceeded with promised comparison of Mainline Industries The MAX, Lionel PH 180 and a pair of PH 180’s set up in parallel feeding input to TIU, with PSX1-AC downstream (for now) set at ~10 amps.
Results, running with 5 to 5.5 amp load, here are the voltage drops at transformer outputs from baseline at no load to running at 5 amp load: The MAX 1.6-1.8 volts; single PH 180 0.8 volt; parallel pair of PH 180’s just 0.4 volt. Besides generally steady running, the parallel setup seems to make for unusually constant voltage and I could run the ore drag almost down to the prototype CNW’s operating rule of 30 mph for loaded ore trains: average 35 mph over 130 ft mainline, with two blocks each fed near center. Curious whether anyone else has had similar benefit from using an “overpowered” setup like this to minimize V drop? I’m inclined to change over to the parallel PH 180’s with PSX1-AC’s place in front of each TIU channel, and any necessary additions like chokes advised in other threads.
The Legacy 360 PowerMaster sounds like I should be considering it for each of the four track circuits as a safe method designed to deal with parallel bricks. Does it deliver the full smooth sine wave when it’s set for maximum output? I gather it chops the wave to produce lower voltage for conventional running, but would that only apply when not delivering the full 18 volts?
I appreciate the patience of each of you who is far ahead of me in these areas. I’m hoping to need only the one TIU, avoiding Super TIU mode, using large power supplies and the PSX circuits set for 15 amps so that multiple trains (2 or 3 including passenger trains) can operate on each channel without overloading it. Passive TIU mode is part of that plan to protect the TIU.
