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JMRI provides powerful tools for working with your layout.

Layout Automation

JMRI can be used to automate parts of your layout, from simply controlling a crossing gate to running trains in the background.

JMRI: Consisting Tool

What is a Consist?

There are three types of consists used on DCC systems:

  1. A basic or primary address consist. In this type of consist, each Locomotive is assigned the same address on the programming track, or on the main with OpsMode Programming (if supported by the command station and decoder). You can use either a long (CV17 and CV18) or short (CV1) address for a primary address consist.
  2. A Command Station Assisted Consist (CSAC). A command station assisted consist is built using a function of your command station.

    Command Station Assisted Consists go by the trade names listed in the table below. The table also lists the known limitations imposed by each manufacturer.

    Manufacturer Trade Name Usage Notes
    Digitrax Universal Consist Limited to number of slots supported by the system. Allows any address to be used.
    Lenz Double Header Limited to 2 Locomotives. Allows any address but 00 to be used.
    NCE Old Style Consist Limited to 8 Locomotives. Allows any address but 00 to be used.
    EasyDCC Standard Consist Limited to 8 Locomotives. Allows any address but 00 to be used.

    The common trait shared by all versions of CSAC is that a separate speed and direction command is sent to the track for each Locomotive that is in the consist.

  3. A Decoder Assisted Consist (DAC), Which is also referred to frequently as an Advanced Consist.

    The NMRA has set aside CV19 as a dedicated location for consist addresses.

    If CV19 contains a value other than 0, the Locomotive will respond to speed and direction instructions on the address in CV19. Otherwise, it will respond to speed and direction commands sent only on the usual short or long decoder address.

    Since the consist address is a single CV, it is limited to the range of 1 to 127. If you add 128 to the consist address, the Locomotive will run backwards (relative to it's normal direction of travel) in the consist.

    For most decoders, this type of consist can be by programming operations in the same ways that a basic Consist can be. We say most here because some decoders block writing to any address CV using operations mode programming.

    The NMRA has also set aside a special command to set up a Decoder Assisted Consist on the mainline. This command should be supported by all decoders that support Decoder Assisted Consisting.

    The advantage to DAC, when compared to CSAC is that only one speed and direction command is sent to the entire consist.

    By default, Locomotives in a DAC ignore function commands sent to the consist address. You can configure some decoders so they will respond to function commands issued to the consist address as well (through CVs 21 and 22). If supported by the decoder, The appropriate values can also be configured through DecoderPro using the Consisting Tab in the comprehensive programmer.

    One final note, Advanced Consists operate in 28 speed steps (always). You may need to make sure your throttle is sending 28 speed steps to the address to avoid flickering headlights.

Consisting Support in JMRI

JMRI provides support for consists using the consist tool, which is accessible through the tools menu of any JMRI application. (There is also a NCE-specific consisting tool that works somewhat differently from the tool described here)

The Consisting tool provides a visual tool for manipulating the Decoder Assisted Consists and, on some command stations, Command Station Assisted Consists.

Backing up the consist tool is a consist manager. The consist manager is responsible for maintaining information about existing consists and for communicating the necessary information between the consist tool and the command station.

Available JMRI Consist Managers

Using the Consist Tool

When you first open the consist tool, you will see a screen similar to the following:

Blank Consist Tool

on the top row are used to select between an Advanced (or Decoder Assisted) Consist and a Command Station Assisted Consist. If the Command Station Assisted Consists are not supported by the tool for your system, these selections will be grayed out.

The box Next to the label Consist: is used to specify the consist ID. For Decoder Assisted Consists, this should be the short address used to identify the consist. For Command Station Assisted Consists, this value may automatically be filled in with the lead Locomotive address when you try to add it to the consist.

Adding a typical ID for a Decoder Assisted Consist should look like the following:

Consist Tool - ID Added

The second line of the consisting tool is used to add Locomotives. A Locomotive may be added either by entering it's number in the box next to New Locomotive or by selecting it's number from the roster drop down box.

Lead Locomotive Selected

Clicking the add button will add a Locomotive to the consist, and it will appear in the list below the second line.

Lead Locomotive Added to Consist

Clicking the reset button will clear the information for this Locomotive.

The Direction Normal checkbox is used to determine if the Locomotive is traveling in forward or reverse when the consist is traveling forward.

You may notice from the previous screen shots that this box is grayed out until a lead Locomotive is selected. With subsequent Locomotives, you can check this box to indicate the direction of the Locomotive relative to the lead Locomotive.

Second Locomotive Selected - Direction Reversed

After adding the second Locomotive to the consist, with the direction reversed, you should see something like the following:

Second Locomotive Added

If you made a mistake, and add a second Locomotive to the consist with the wrong direction, you can change it's direction simply by clicking on the checkbox in the Direction Normal column.

Second Locomotive - Direction Change

The direction of the lead Locomotive cannot be changed once added.

To delete an individual Locomotive from the consist, you can select the Del button in the right most column of the appropriate row of the table of addresses.

To delete an entire consist you can use the Delete button at the bottom of the screen.

The throttle button at the bottom of the screen can be used to bring up a JMRI throttle for this address.

To Add a new consist, you can select the blank entry in the drop-down box next to the current consist's ID.

Select New Consist

To Recall an existing consist, you can select the appropriate entry from the drop-down box next to the current consist's ID.

Select a Consist