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Related Topics DCC Explained mfx Explained Motorola Explained RailCom Explained Compare Command Stations Decoder Finder Digital Decoders
Address digital locomotives individually

Change a Locomotive Address: Configure DCC, mfx & Motorola

Every digital locomotive requires a unique assignment. This guide explains short and long DCC addresses, CV 1, CV 17, CV 18 and CV 29, automatic mfx registration and address assignment with modern digital command stations.

Change the Address Calculate CV Values Command Stations & Decoders
Märklin 60226 Central Station 3 for managing locomotive addresses Roco 10820 Z21 digital command station for programming DCC locomotive addresses
The quick answer

How can the locomotive address be changed?

Place the locomotive by itself on the programming track, open locomotive or decoder programming on the digital command station and enter the required address. For a short DCC address, CV 1 is normally changed. Long DCC addresses are stored in CV 17 and CV 18 and are additionally activated through bit 5 of CV 29.

Modern command stations perform this calculation automatically. Whenever possible, select a menu item such as “Locomotive Address”, “Change Address” or “Long Address” instead of changing CV 17, CV 18 and CV 29 individually.

With mfx , the locomotive normally registers automatically. The visible locomotive name and internal system entry are then more important than a manually assigned DCC address. A multi-protocol decoder may still have an additional DCC or Motorola address.

Before programming
Place only one locomotive on the programming track

If several vehicles are located in the programming section, all connected decoders may receive the same command. Record the previous address and test the new address immediately after writing it.

Manufacturer ranges and digital systems

Manufacturers for decoders and address programming

The manufacturer and system pages provide access to suitable decoders, digital command stations, programming devices and additional information.

Understand the differences between DCC, mfx and Motorola

Which locomotive address is actually being changed?

Short DCC address

The short primary address is stored in CV 1. The DCC standard provides the range from 1 to 127. Some command stations automatically treat addresses from 100 upwards as long addresses.

Long DCC address

Addresses from 128 to 10239 are stored in CV 17 and CV 18. Bit 5 in CV 29 determines whether the decoder uses this long address.

mfx or M4

A compatible locomotive registers automatically with the command station. The locomotive name, function symbols and system ID are transferred during registration. The additional DCC address remains a separate setting.

Motorola or fx

The address is assigned through the command station's locomotive menu or, with older decoders, through coding switches. The available range depends on the decoder and control device.

Multiple-unit consist

A DCC consist address is normally stored in CV 19. It does not replace the normal locomotive address, but enables several vehicles to be controlled together.

RailCom feedback

Suitable decoders can report their address to compatible command stations or detectors. This supports vehicle detection, diagnostics and automated fleet management.

Address type Storage or management Typical use
Short DCC address CV 1, with the long address disabled in CV 29 Small layouts, clear locomotive lists and easy-to-remember numbers
Long DCC address CV 17, CV 18 and bit 5 in CV 29 Running numbers, large collections and extensive DCC layouts
mfx / M4 Automatic system registration Märklin Central Station, Mobile Station and compatible multi-protocol systems
Motorola / fx Decoder or command-station setting Older and current Märklin-oriented digital vehicles
Consist address DCC CV 19 Double heading, banking locomotives and permanently coupled locomotive groups
Tool for DCC addresses

Calculate the CV values for a locomotive address

Modern command stations normally calculate long DCC addresses automatically. The calculator nevertheless shows which CVs are involved. This is useful for troubleshooting, comparing settings with decoder instructions and using command stations that require individual CV values.

Enter the required address and the current value of CV 29. The calculator retains the other CV 29 settings and changes only the bit used for short or long addressing.

Read CV 29 before changing it manually. This value may also affect the direction of travel, speed steps, analogue operation and the selected speed curve.

DCC Address Calculator

Calculation for addresses from 1 to 10239.

Long DCC Address
CV 1 unchanged
CV 17 192
CV 18 218
New CV 29 value 38

This calculator is a planning aid. Prefer the address assistant provided by your command station and check the decoder instructions.

Move safely from the old address to the new one

Change a locomotive address in eight steps

1

Identify the digital protocol

Check whether the vehicle is controlled through DCC, mfx, Motorola, Selectrix or several protocols. The address change must match the system currently in use.

2

Place the locomotive on the track by itself

Use an electrically isolated programming track. Clean the wheels and track when necessary so that the decoder receives the programming command reliably.

3

Read the old address

Read CV 1 and CV 29 or the locomotive data stored in the command station. Save or record the previous setting.

4

Select the new address

Assign a number that is not already in use. DCC addresses from 128 upwards require long addressing.

5

Use the address assistant

Open locomotive editing on the command station and select a short or long address. The command station should write all required CV values together.

6

Briefly interrupt the power

Remove the locomotive from the track briefly after writing the values. If an energy-storage module is installed, wait until its stored energy has discharged.

7

Test the new address

Drive slowly in both directions and test the lighting and one auxiliary function. If problems occur, also test the previous address.

8

Update the locomotive list

Store the address, locomotive name, manufacturer, decoder type and protocol in the command station or vehicle documentation.

Use a menu instead of calculating individual CVs

Change locomotive addresses with popular command stations

Menu names may vary between firmware versions. However, the basic procedure remains comparable.

Märklin Mobile Station 2

mfx locomotives register automatically. DCC and Motorola vehicles are edited through the locomotive record. Check the selected data format before changing the address.

Märklin Central Station 3

Open locomotive editing and change the address or protocol in the vehicle record. With mfx, system registration is managed automatically.

Roco Z21 and multiMAUS

The DCC address can be changed through locomotive management or CV programming. Use the dedicated address function for long addresses.

PIKO SmartControl WLAN

Edit the vehicle in the locomotive database and write the new address on the programming track. RailComPlus-compatible vehicles may also be detected automatically.

ESU ECoS

The locomotive address is changed conveniently in the vehicle settings. Multi-protocol vehicles can be configured for DCC, Motorola or M4.

Uhlenbrock Intellibox

Use locomotive or CV programming and check the selected data format. Long DCC addresses are most safely written through the dedicated address dialogue.

Address conflicts and programming errors

Why does the locomotive not respond after the change?

The wrong address type is active

CV 1 was changed, but CV 29 still activates the long address, or vice versa. Use the command station's address assistant.

The protocol does not match

The locomotive was created as a Motorola vehicle even though the decoder should be addressed through DCC. Check the locomotive record and decoder format.

Two locomotives move at the same time

Both vehicles have the same primary or consist address. Place each locomotive on the programming track individually and assign unique numbers.

The programming command was not received

Dirty wheels, poor current collection or a programming track that is not electrically isolated may prevent the value from being written.

The mfx locomotive appears twice

An old manual record and the automatic mfx registration may exist at the same time. Delete the incorrect record, not the decoder.

CV 19 is still active

A stored consist address may cause the locomotive to respond additionally to commands sent to a multiple-unit consist.

Suitable digital technology at Modellbahnshop

Digital command stations, programmers and decoders by gauge

Digital command stations change locomotive addresses conveniently through the vehicle menu. Programmers make extensive decoder projects easier. A new decoder must match the model's interface, protocol, installation dimensions and permitted current.

Suitable for several gauges

Digital command stations and handheld controllers

For driving, managing and programming locomotive addresses.

Workshop equipment and decoder maintenance

Programmers and testing devices

Wide selection of interfaces

Locomotive decoders for H0 gauge

Compact designs

Locomotive decoders for TT, N and Z gauges

More power for large vehicles

Decoders for Gauges 0, 1 and G

Explore related digital topics

Related guides to addresses, decoders and command stations

Digital protocol

DCC explained simply

Learn about addresses, speed steps, functions and CVs.

Open guide → Automatic registration

mfx explained simply

Understand locomotive registration, function symbols and system management.

Open guide → Märklin digital format

Motorola explained simply

Understand address ranges, older decoders and modern command stations.

Open guide → Feedback

RailCom explained

Understand address, speed and CV feedback.

Open guide → Buying guide

Which digital command station is right for you?

Choose a command station by protocol, layout and preferred operating method.

Open comparison → Decoder installation

Compare decoder interfaces

Understand the differences between Next18, PluX, 21MTC, NEM 651 and NEM 652.

Open interface guide →
Frequently asked questions about vehicle addresses

FAQ about changing a locomotive address

Which CV contains the locomotive address?

The short DCC address is stored in CV 1. A long DCC address is stored in CV 17 and CV 18 and activated through bit 5 of CV 29.

Which address does a new DCC decoder use?

Many new and factory-reset DCC decoders initially use address 3. The default address may be different in factory-equipped vehicles.

What is the difference between a short and long address?

Short DCC addresses are managed through CV 1. Long addresses support larger numbers up to 10239 and require CV 17, CV 18 and activation in CV 29.

Can I use the locomotive's running number as its address?

Yes, provided the number is within the supported address range. Four-digit running numbers are particularly suitable as long DCC addresses.

Why do two locomotives move with one controller?

Both vehicles probably have the same primary or consist address. Program the locomotives individually and assign different addresses.

Does an address have to be entered for mfx?

Normally not. An mfx locomotive registers automatically with a compatible command station. A multi-protocol decoder may also have an additional DCC or Motorola address.

Can the locomotive address be changed on the main track?

DCC decoders can often be addressed through Programming on Main. A separate programming track is nevertheless safer for changing the primary address, especially when the old address is unknown.

Why does the long address not work?

CV 17 and CV 18 may have been written without activating bit 5 in CV 29. Use the command station's address assistant so that all values are set together.

What is the consist address in CV 19?

In DCC, CV 19 contains an additional address for multiple-unit consists. The normal primary address remains stored in the decoder and may still be used for individual functions.

How do I find an unknown locomotive address?

Place the locomotive by itself on the programming track and read CV 1 and CV 29. If the long address is active, CV 17 and CV 18 must also be evaluated. mfx and RailCom-compatible systems may detect vehicles automatically.

A unique address ensures reliable digital operation

Discover further instructions, comparisons, digital technology and product recommendations in the central model railway guide.

Open the Model Railway Guide