Greetings all:
For your consideration, here is another interesting DCS environment, only as a bit of a foil in light of the discussion above.
I run trains off of overhead catenary, and always have. No motors on my roster have rollers. My layout is not huge by any stretch, maybe ~45ft or so of track on the loop, and another 30ft or so for the siding, spurs and yard, (roughly).
When I had only 1 or two motors going at once, I fed the entire system off of one TIU fixed channel at the northern-most switch on the main loop, (I know, not very good practice). Even so, the loop's catenary is electrically isolated from that of the siding, spurs and yard. Predictably though, when I hit 6 or 7 motors online at once, the system started misbehaving; signal strength was bad (3-7, with a few 10s), and there were an increasing number of "out of range" errors on selecting motors from the remote.
I finally found some time recently to do some re-wiring. Now the loop catenary is on TIU Variable 1 (set as fixed, to accommodate the occasional conventional run) and the siding, spurs and yard are on TIU Variable 2, (also set as fixed). Both feeds go through a PSX circuit breaker before connecting to their respective TIU inputs. There is still only one electrical / DCS feed point per catenary circuit, and at the same place as before, (the northern-most switch on the loop). Trains flawlessly transfer from one circuit to another when coming off of the loop.
Now, there are 12 motors that power-up at once; roughly 1/3 on the loop and 2/3 in the spurs and yard. Signal strength and performance has been perfect. Please do not misunderstand me; I do not say this to be boastful or denigrating to Barry in any way, but just for the sake of discussion. It seems that if one had an uninterrupted run of conductor, as a good stretch of catenary wire would be, then all the resistance points caused by track connections would be removed (even the reduced resistance of a track connection that was soldered), and thus get much more trackage from a DCS signal / TIU channel, right? (Note this discussion is only about DCS signal; channel current is not a consideration as I rarely draw more than an amp or 3 with most of the motors powered up).
I realize few will scratch-build a catenary system to run trains from, and so this post will be largely irrelevant to most of the audience. However, I throw it out there for the sake of discussion. Thanks.
