What do the different terms and functions mean on DCC?

Hornby DCC Elite Train Controlller

Many of you will by now have seen or bought Hornby DCC (Digital) locomotives, controllers, decoders or accessories – but what do the terms and functions actually mean?  We’ve compiled a list of the most common terms with our colleagues at Hornby’s Technical Services team…

Acceleration Delay

The delay between the locomotive being stationary and reaching the desired speed.


Deceleration Delay

The delay of a locomotive slowing down to a standstill.


Accessory Decoder

An electronic decoder designed for use with track side accessories such as points or signals.An accessory decoder is not for use in a locomotive.



A number used to identify a locomotive or accessory that is either equipped or linked to a Decoder.


Feedback (Load Compensating)

This allows a locomotive to remain at a constant speed regardless of loads being pulled or incline being negotiated.



Technical term for wires that carry electrical signals around a model layout.


Command Station

The Command Station is the ‘brains’ of a DCC system.  A Command Station is in essence a micro-computer/controller that communicates with the decoders that are located either in a locomotive or connected accessory.  The computer transmits signals to the decoders instructing them what to do, such as accelerate, decelerate, brake or switch lights on or off.


Configuration Variable (CV)

A technical term referring to the operating information of the particular locomotive or accessory that is stored on the specific decoder.This information will remain “set” until changed using the Command Station.



Consist is an American term, but in the UK it is known by Double or Triple Heading.  This is where two or more locomotives are brought together and function as one.  There are three types of Consisting;

  1. Basic consisting where the locomotive decoders in the Consist have the same address.
  2. Universal Consisting where the Consist information is stored in the Command Station.
  3. Advanced Consisting is where the Consist information is stored inside the decoder.



Digital Command Control.  The application of computer technology to control the movements of locomotives.  Each locomotive is fitted with a decoder (or ‘chip’) which is uniquely programmed and recognises its own identity and responds only to those control signals which are addressed to it.  DCC also allows a wide range of extras including controllable lighting and on-board sound.  The accepted standards have been laid down by the NMRA (National Model Railroad Association) an American Association.


Locomotive Decoder

A small PC board which contains a ‘chip’ that stores control information; normally fitted in locomotives.  The Command Station sends coded information to the decoder which can then control the locomotives speed, direction and any operating functions that the locomotive may have e.g lights.  Locomotive Decoders can be fitted to accessories that have a motor as a drive for example the R070 Hornby Turntable.


Occupancy Decoder

A unit that can detect the presence of a locomotive on a specific section of track and can provide the appropriate information as ‘return’ data.


Power Bus

Copper strip or wires that can relay power from a Power Booster to the track.


Power Booster/Power Station

A Power Booster or Power Station is as the name implies, there to provide a boost of power to the track.  This can occur if a larger than normal quantity of locomotives are required to be running on the track at the same time.  If the transformer already fitted cannot handle this number then it will be necessary to section the layout and fit a Power Booster.  This Booster will not only provide more ampage to drive the locomotives but also boost the signals to the Decoders.  All Boosters fitted must still be connected to the Power Station.



The process of assigning an Address to a locomotive or accessory (points or signals).  The process of programming sends a signal containing a numerical identifier to the locomotive being programmed.


Programming Track

A section of track isolated from the main layout purposely for programming locomotives.  A Programming Track negates the requirement of removing other locomotives from the main layout.


Speed Steps

A variable voltage increase used to control motor speeds.  Decoders can set the output power for each speed step.


Stall Current

Stall Current is the maximum current draw in amperes that a locomotive is capable of when stalled.  If the armature of a motor is prevented from turning and the maximum voltage is applied the current draw of the motor is known as the “Stall Current”.


Throttle Notches

Determines whether a locomotive is controlled with 8, 14, or 18 speed steps.



A high-speed communication protocol used for connecting Digital input devices together.


XpressNet (XBUS) Input Devices

Devices using the XpressNet protocol to control a digital layout.

Hornby Class 43 HST DCC decoder installation guide

This guide is designed to help you with the installation of an R8249 or TTS Sound decoder with Class 43 HST models.  Please note that your model may not be exactly the same as the model used in this guide, and it is representative only.

As with all modifications, these are carried out at the owners risk and we cannot accept any responsibility for any damage caused.



Step 1:
Carefully remove the body by gently pulling the body sides apart and then pulling the rear of the power car down. You can refer to your locomotive service sheet for further guidance.

Step 1


Step 2:
Locate the motor at the rear of the power car. It will have red and black wires going to it from both the front and rear of the chassis.


Step 2


Step 3:
Unsolder the red and black wires where they are connected to the motor and capacitor. Do not cut the wires any shorter as they will be needed when installing the decoder.


Step 3


Step 3


Step 4:
Remove the decoder from the protective packaging, taking care not to handle the PCB directly as this will cause irreparable damage due to static electricity.

It is important to protect the decoder by wrapping the PCB with insulating tape.  To prepare the decoder, remove the plug and separate the red, black, orange and grey wires.  The rest can but cut short and insulated.  Strip the red, black, orange and grey wires and lightly “tin” them with solder.  Tinning the wires will make the installation easier.


Step 4: Decoder preparation


Step 5:
Soldering in the chip is fairly straight-forward. Solder together the 2 black wires from the wheel pickups to the black wires from the decoder.

Similarly solder together the 2 red wires from the wheel pickups to the red wire from the decoder.  The orange and grey wires from the decoder are then simply soldered to the capacitor legs as shown.  The decoder can then be attached on to the lead weight using insulating tape.  It is recommended that all solder joints are wrapped with insulating tape.


Step 5


Step 6:
Once the decoder is secured, place the locomotive on the programming track and test to make sure that the installation has been successful.

Remember that the decoder has a default number of “3” and it is recommended that you code the locomotive to the number you require and test again.  Also test that the wires and decoder cannot become caught or trapped by the gears of the motor bogie during operation.


Step 6


Step 7:
Carefully replace the body onto the chassis taking care not to trap any wires during this procedure. Test once more to ensure that the installation has been totally successful.


Step 7

How do I convert my turntable to DCC?

Turntable wiring guide

There are some Hornby accessories that may function better under the control of the R8249 locomotive decoder instead of the accessory decoder.  These include the Hornby R070 turntable.  The use of a Locomotive decoder will allow for fine control of the motor speed in these accessories.

Modifying the turntable for DCC operation

Please note that modifying the below accessory requires use of a soldering iron and should only be carried out by an experienced modeller who is competent with making the required modifications.

Please note with any DCC conversion or other modification, this is only a guide and we cannot accept any responsibility for any damage caused.  As with all modifications, these are carried out at the owners risk.


Turntable contact removal
Turntable contact removal

For operation of the Turntable, the contacts at the end of each rail must be carefully removed.  If left in place they will cause a short-circuit.

    • Locate the brass contacts at the end of each rail on the rotating Turntable section.


  • Gently slide the contact out from under the rail.
  • Repeat this process for the end of each rail.



Wiring the turntable

Follow these steps to wire up the turntable:

  • Cut the plug off of the R8249 Locomotive Decoder and strip the RED, BLACK, ORANGE and GREY wires ready for soldering.
  • Cut the plugs off both the BROWN and BLACK wires that protrude from the base of the Turntable and strip them ready for soldering.
  • Solder the ORANGE wire from the decoder to the BROWN wire from the Turntable and wrap the join with insulating tape. Similarly, solder the GREY wire from the decoder to the BLACK wire from the Turntable and wrap the join with insulating tape.
  • It is necessary for the RED and BLACK wires from the decoder to be connected to the track. For ease of use it is recommended that the RED and BLACK wires from the decoder are connected to RED and BLACK wire from the track are joined together using an electrical terminal block.
  • Ensure that all remaining wires from the decoder are individually wrapped with insulating tape to prevent short circuits.

This wiring guide will help you.


Turntable wiring guide
Turntable wiring guide


Please note: You must ensure that any turnouts from the modified turntable are live in order for locomotives to operate.



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How to install the Hornby Elite & E-link driver for RailMaster (Windows XP-8)

Hornby eLink and Railmaster Combination Pack

Download the instruction manual



Find out all about how to install and operate your Railmaster DCC system with this downloadable guide.

With the increasing number of different versions of Windows operating systems and the substantially different ways they work, this guide has been written to provide step-by-step guide to show you how to install the Hornby Elite and eLink USB port drivers onto your PC.

This guide will hopefully show you every scenario and should serve as the definitive document for ensuring the correct installation of the Hornby Elite and eLink driver on your PC.
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Download the instruction manual

Hornby Railmaster Instruction Manual (English)

Hornby eLink and Railmaster Combination Pack

Download the instruction manual



Find out all about how to install and operate your Railmaster DCC system with this downloadable guide.  Includes information on the following areas;

  • Installing RailMaster
  • Setting up your Hornby DCC Controller
  • System Settings
  • Setting up Locomotives
  • Controlling Locomotives
  • Voice Control
  • Reading and Writing Locomotive CVs
  • Programming Accessory Decoders
  • Designing a Track Schematic
  • Double Heading Locomotives
  • Programming to Automate your Layout
  • Programmable Floating Keys
  • Clock
  • Command Line Options
  • Programming Commands & Functions
  • Upgrading and Activating the Software
  • Requesting Help and backing up data
  • Important Notes on Scale Speeds and Accurate Loco Control
  • Troubleshooting Guide

Please note, this manual gives reference to Railmaster Plus add-ons but these are not available as standard with the controller pack.  Unfortunately, we cannot offer any technical support on the Plus features.


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Download the instruction manual