A power supply is needed to supply your Digitrax DCC system. This power supply will be responsible for powering all locomotives on the layout at one time. So generally this will need to be heavier duty than a normal single unit power pack. The power supply needs to put out at least 12 volts, either AC or DC. Maximum is 22 volts AC or 28 volts DC.

Each Digitrax booster unit will handle up to 5 amps of power (some have even greater capacity). Digitrax has released a fully assembled power supply, the PS515. This supply delivers 5 Amps at 15 volts AC.