Chris: In your post, I think you meant Voltage when you said Amperage. Voltage regulates the speed; the loco then consumes Amperage, which is so many billion electrons passing a given point. Multiply volts by amps and you get Watts. (May also be called VoltAmps) If your loco consumes 1/2 amp at full load, to run at full speed (12V) takes 6 watts. 2 locos take 12 watts. If you check the power packs, they should have a rating in either watts or amps. Train set powerpacks sometimes deliver only 1/2 amp -- there's no room for expansion. Although I don't do it, I think DCC is the way for anyone starting. But there are problems. Fitting the chips in can be hard in HO; in N there is even less room and they fill more of the loco with motor and weight. Check your dealer (or some other dealer) to see if there are chips designed for the loco you want to buy. And you can wire your layout for DC in a way that you can change to DCC with no major work.