The answer to this question applies to all Empire Builder sets including Super Empire Builder Xtra
Q: I have just purchased a Super Empire Builder set. My expectations are for it to operate an N-Scale switching layout right now with future expansion to a larger N-Scale layout. I am a little confused as to which power supply I would need at this time. I am reading about power supplies and inline fuses, all of which is a little overwhelming to me as I am getting back into the hobby. Can you recommend which power supply will be better for me as I start the DCC experience? I want to keep strictly to Digitrax for all of the components that I use for my DCC set up. I am interested in the PS515 and PS2012 power supplies.
A: You need to consider the following:
The Power Supply
Digitrax PS515 is rated at 5 Amps (PS514 newer model of this power supply), the Super Empire Builder is rated at 5 Amps, so they are matched to each other.
Digitrax PS2012 is rated at 20 Amps, four times what you need for the Super Empire Builder. PS2012 is designed to operate multiple command stations and/or boosters at the same time. It is a good choice if you will use additional boosters to run more trains on the layout.
No matter how much power you try to squeeze into the Super Empire Builder, only 5 Amps will be output, the rest will be dissapated as heat.
Likewise, were you to power the Super Empire Builder with the 3 Amp PS315, the Super Empire Builder would only put out 3 Amps. Everything will work, but you will not be able to operate as many locomotives as you could at the full 5 Amps.
That said, the choice centers on what your ultimate needs will be. Once your railroad grows to a larger size, the command station/booster (in this case, the Super Empire Builder) will let you know that it has reached its capacity. You may see that it shuts off abruptly, an indication that the internal circuit breakers sense too much power consumption. At that point, you should divide your railroad into power districts, each with its own booster (such as the DB150 and others) and its own power supply. All the power districts are connected via LocoNet. Each booster receives packets from the command station via LocoNet and combines it with the power from a power supply and send it to its power distict to run the trains in that district.
So, your question is "Do I just buy the 5 Amp power supply now and add more as my needs increase?" Or, "Do I buy the 20 Amp power supply now and have enough power from one unit to meet my future needs?" Your call.
As far as inline fuses are concerned, Digitrax does recommend doing so, with the fuse being rated at the same Amperage as the rated value of the command station; in the case of the Super Empire Builder, that would be 5 Amps. This fuse would be placed between the power supply and the Super Empire Builder.
Once your railroad is powered, you may find it helpful to add the PM42 Power Manager to each command station/booster and booster. This divides the power district further down into four sub-districts. Many modelers do so to power their track with some of the PM42 sections, have automatic reversing for one or more nodes and to power their turnout motors. Using one node to power the turnouts makes problem solving easier. When a train derailment causes a short, the turnout that caused the derailment can still be operated to remedy the problem. Without the PM42, turnout power would shut down with the rest of the system.