DCC FAQs - for beginners

These are in no particular order right now. If you are a beginner, your question is probably here. If not, email me and I'll add it!

I have this section here because many people now use DCC in G scale, since often they used it in a smaller scale.

Why does my locomotive run so slow on DCC?

  1. The DCC system can use a couple of volts from input of power supply to the output to the rails.
  2. The decoder in your loco can lose a couple of volts between the track and the motor.
  3. At top speeds a couple of volts can make a difference of 10 scale miles an hour or more.
  4. Your locomotive was pretty slow already, like Aristo 6 axle diesel locos.
  5. your DCC voltage is too low, aim for 24 volts DCC on the rails.

How do I know what voltage is on the rails? My meter reads funny.

DCC is a form of AC, but not exactly like the sine-wave shape of the AC in your wall outlet. It is a square wave of varying frequency. Ordinary (read cheap) meters cannot measure DCC track voltage correctly. Your meter must say it is a "true RMS reading AC voltmeter". You can buy one of these (usually over $100), or get the RampMeter from Tony's trains, that will measure DCC and DC and AC and amps. Highly recommended. Barring that, you can hook a full wave bridge rectifier to the rails (the ac inputs) and then read the resulting DC on the + and - outputs of the bridge with an ordinary DC voltmeter. You might want a small filter cap on the DC side.

Why doesn't my locomotive run?

This is the most common question, frequently associated with no more information. You need to check your installation out, start from the tracks to the decoder. Put the decoder on the programming track and see if you can communicate with it. If not, STOP and check your wiring. 

Some decoders, like the QSI, have a "startup sequence" and you need to "start" the loco before it starts making noise and moving. Likewise, many decoders (again like the QSI) have "Disconnect" or shutdown commands that will "disconnect" the motor, like it is neutral. In all kindness: read the dang manual!

How do I choose a system?

There is a lot of history in DCC, and many different systems. While the fundamentals are all the same, there are wildly different implementations of how you use the throttle.

Each "camp" believes it is the best, of course. Be sure to try to see and operate different systems before making a decision, it takes a fair amount of knowledge to make the "best" decision, and MOST companies try to "lock you in" to their unique features. It's good and terrible. Extra features are nice, but can severely limit your options as you expand.

Read up on the DCC "entry" page to get started: DCC "entry" page




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