08-28-2010, 01:40 PM
Just a minor (anal?) addition to all the calculations above. A 200 watt power supply doesn't always use 200 watts. It depends on how many and what type of locos are being run. If the PS is plugged in but no trains are running, the current draw is quite low, just a bit of magnetizing current in the transformer and a small amount of heat lost in the electronics and such. As we add locos to the layout, the amperage increases per loco. The 200 watss is the maximum, not the "all the time" power.
Three Foot Rule In Effect At All Times