4 Mainlines How Many PWR56's?

[Coupe633]

I am new to RailPro and have my first dozen modules installed in their respective locomotives and programmed. Just 40 more to go. My layout is in the design process and I will soon start construction in my 60 x 40ft space. To keep it simple enough for this post I will have 4 mainlines running fairly parallel with each other but we are talking about a 200 - 300 ft loop each. I have been considering how to wire this and it occurred to me that the single PWR56 I have may not be enough. While the Ring Engineering Website says it can run up to 15 modern locomotives, it is doubtful that I can run half that by myself at the same time. My main concern is that I may not have enough power to run that much length. My first thought was to connect one PWR56 for each mainline with insulated rail joiners separating the mainlines at any turnout that takes a train from one mainline to another. The wiring of jumper wires at short intervals seems fairly simple but I am now more concerned that the length will be a problem. I have browsed though previous threads but none touched on this topic directly so here are my questions. Instead of a single PWR56 for each mainline powering 200 - 300ft of track independently would it be more advisable to use a PWR56 to power all 4 mainlines plus sidings and yards for one quadrant and additional PWR56's of each additional quadrant? This would shorten the length but widen the area of coverage. If this would be the preferred method should I install insulated rail joiners between the quadrants so that each quadrant is an isolated buss  to service all the track in that area which includes 4 mainlines. Now we are back to blocking track like we did back in the old days of DC. I have read the posts regarding using a larger gauge wire for the buss or power distribution under the layout. Any comments suggestions would be very helpful. It's not too late to turn back at this point. I can adapt.

[Alan]

PWR-56 determines how many trains can be run simultaneously.
Bus wire gauge determines how long the track can be.

Use big bus wire, don't use insulating joiners (unless you do so for occupancy detection).

[Coupe633]

I prefer to use one PWR56 for each mainline and use large gauge main buss wire to carry the power to the entire mainline.  This would be simple and wire is not expensive.

[JD of Georgia]

This question is not how many mainlines, but how many locomotives.  Each pwr-56 can support up to 4 amps (56 watts at 14vdc). Allow a 25% safety, let’s use 3 amps.   I base my layout on the estimate that most HO locos will not exceed .5 amps.  So you can run 6 locos on a single power supply.   Work it from there for your layout.