N scale electrical troubleshooting

[Anonymous]

After a lapse of several years my grandson and I are building a N scale layout. Using atlas track, turnouts, and electrical components. Have 1 complicated reversing section. We cannot seem to keep the power to the layout for any period of time. Seems like power packs overloading. Need patient replies to guide through finding source of problem. Only need 1 power pack for layout as it is 3'x7' without a lot of track. Power packs available are 2 MRC 501N of mid '70's vintage, and a MRC 220. The 501n's have variable DC and 12v DC terminals. Which is correct to use on track.? The 220 has only variable DC so that is probably the correct ones. The 220 seems to not give but 10% of the rated power as measured by an electrician friend. Saw something on here in the past about "frog direction". Could this be the problem? Wired using the common rail and isolated blocks to control segments of track.