Just an FYI, I have a large N Scale layout.
It is one big block. No isolators.
I run 2 double headed trains at a time.
The layout barely pulls 1 Amp.
Maybe 1.2 Amps when the engines are cold.
This is what my RRamp Meter is telling me.
It is wired between the Command Station & the track.
My base load is about .75 Amp at idle.
That is because I have over 30 engines on sidings ready to go.
So, 4 engines pulling trains are barely pulling over .5 Amps.