duncan1_9_8_4 said:
On behalf of my dad, how does the above item work? Is it one per reverse loop, and is it track mounted or controller mounted. Do you have to stop like on the analouge ones, or can you run continuousley? He has two turning circles. Not good with wires lol.
If we are talking about the LGB 55080, then it is a very simple device and there is no point in having more than 1 per layout, as I'll explain. Note that LGB's instructions say you should have 1 per return loop: this is, I'm afraid, deliberately misleading. You can run through the loop without stopping, so the system lends itself to running "hands off".
As an aside, the Massoth return loop modules can work in two modes which I'll call "simple" and "clever": "simple" is identical to the LGB 55080; "clever" mode is much better, but to use it you DO need one reverse loop module for each loop/wye.
In "simple" mode, the electrics work by detecting if there is a short circuit on the main part of the layout. That's caused by the mismatch between polarity on the layout's main part and the loop. If there is, the loop track's polarity is switched, effectively instantaneously, by means of a DPDT (dual pole, dual throw) switch inside the 55080. It's a neat solution, but there are two drawbacks. First, because the short circuit is detected on the main track, ALL 55080s connected to that main track "see" the short and switch at the same time. Hence there is no benefit in having more than one 55080 on a layout. Second, although the polarity switch is very fast indeed, you can detect it by loco lights flickering and you can hear the spark between rail and the leading loco wheel. The sparking is undesirable both for wear on electrical components and contamination of both rail and wheel, though I suspect you'd have to operate for a long time before either became an issue.