THE BIT TO REMEMBER
An address chooses the locomotive. A CV changes a setting inside its decoder.
An address is not the running number
You choose a supported address; it does not have to equal the number on the body. Two locomotives sharing an address can both respond, so keep a list. Controller and decoder address ranges vary.
A CV is a numbered setting
CV stands for Configuration Variable. Settings can affect acceleration, braking, lighting and other behaviour. Their meaning and available values depend on the decoder. A function button such as F1 is not the same as CV1.
Change one thing at a time
Use the exact decoder manual and the controller’s programming procedure. Save the original value before changing it. A programming track is a separate track connection used by systems that support it; follow that system’s isolation instructions.
Avoid the universal reset trap
Reset procedures vary. A reset can remove settings you wanted to keep. Identify the decoder and read its instructions before using any reset value.
A REAL-WORLD EXAMPLE
You might give a Class 37 address 37. Selecting 37 lets you drive it. An acceleration setting then changes how gradually it responds when you turn up the speed.
Your next step
- Record the current address.
- Find the exact decoder manual.
- Note the original setting, change one value, then test.
- Save useful changes and the function list in My Collection.
Read the original instructions
Reviewed 7 October 2026. These beginner notes do not replace the instructions for your exact model.
Hornby · DCC glossary ↗Digitrax · controller and programming instructions ↗