KB652: DT300 - Multiple Unit Operations

This article was last updated on July 31, 2011, 2:11 p.m. | Print Article | Leave Feedback


Many prototype trains use multiple locomotives to provide the necessary power to pull or push the train. This practice is called Multiple Unit consisting, usually shortened to MU or consisting.

The DT300 Throttle can provide three methods of consist control:

1. The Basic Consisting method, which is not commonly used, is to program all the locomotives in a consist to the same address and run them on one throttle. In this case all the locomotives must be headed in the same direction, head to tail, head to tail, head to tail. If you use decoders that allow you to set the normal direction of travel of each loco, you can program locos in a basic consist to run head to head and/or tail to tail.

You probably won’t use this method very often in your operations because of its limitations. The basic method is the only method available to most basic command stations. We mention it here only because it is an option.

2. The Advanced Consisting method handles consist information in decoders that are capable of doing advanced consisting. When you use advanced consisting, your options are somewhat limited because you can’t use all DCC decoders and you can’t include analog locos in your consists. If you choose to use Advanced Consisting, please see the information about status editing in your system manual and decoder manual for set up.

3. The UniVersal Consisting method handles consist information in the command station and allows you to consist locomotives with any DCC format decoder and analog locos as well.

Locomotives can be added to and removed from the consist in any orientation, head to head or tail to tail. This method has the advantages of flexibility and the ability to use all DCC decoders in consists. UniVersal Consisting is the Digitrax preferred method of consisting.

With UniVersal Consisting you can add a locomotive to a consist in either orientation and in any physical location in the train. When you send commands to the consist you use a single address and the command station handles the rest of the commands to the other locomotives in the consist. Since the address you will use to control the consist is not necessarily the address of the lead or head end loco, Digitrax has chosen the term “TOP” locomotive address for this special address. It usually will be the train number.

  • Digitrax defines the TOP loco as the loco on the R THROTTLE knob at the time when the MU add is performed. By definition, Digitrax always adds loco addresses to the “TOP” loco address in a consist.


  • The “TOP” loco is special–it is the address that receives the speed and direction commands for the entire consist.


  • All loco addresses added to the consist are controlled by commands sent to the “TOP” loco. Once added to a consist, the text area above the address will display cn for a single loco and mid for the top loco of a nested consist


  • The TOP locomotive address does not have to be a physical loco on the track, it can be a phantom.


  • All loco addresses in a consist will have the same status as the TOP loco. They will all be common, in-use or idle based on the state of the TOP loco.


  • Each loco within a consist maintains its original advanced 28/128 or standard 14 speed step mode setting.


  • A consist can be released by one throttle and then selected and run by any other throttle.


  • A consist TOP address can be dispatched and acquired on another throttle just like any other address.

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