RailRoad generates models and controllers diagrams in DOT language for a Rails application.


Run RailRoad on the Rails application's root directory. You can redirect its output to a .dot file or pipe it to the dot or neato utilities to produce a graphic. Model diagrams are intended to be processed using dot and controller diagrams are best processed using neato.

railroad [options] command


Common options:

-b, --brief                      Generate compact diagram
                                   (no attributes nor methods)
-e, --exclude file1[,fileN]      Exclude given files
-i, --inheritance                Include inheritance relations
-l, --label                      Add a label with diagram information
                                   (type, date, migration, version)
-o, --output FILE                Write diagram to file FILE
-v, --verbose                    Enable verbose output
                                   (produce messages to STDOUT)

Models diagram options:

-a, --all                        Include all models
                                   (not only ActiveRecord::Base derived)
    --hide-magic                 Hide magic field names
    --hide-types                 Hide attributes type
-j, --join                       Concentrate edges
-m, --modules                    Include modules
-p, --plugins-models             Include plugins models
-t, --transitive                 Include transitive associations
                                 (through inheritance)

Controllers diagram options:

--hide-public                Hide public methods
--hide-protected             Hide protected methods
--hide-private               Hide private methods

Other options:

-h, --help                       Show this message
    --version                    Show version and copyright


-M, --models                     Generate models diagram
-C, --controllers                Generate controllers diagram
-A, --aasm                       Generate "acts as state machine" diagram


railroad -o models.dot -M 
  Produces a models diagram to the file 'models.dot'
railroad -a -i -o full_models.dot -M 
  Models diagram with all classes showing inheritance relations
railroad -M | dot -Tsvg > models.svg
  Model diagram in SVG format
railroad -C | neato -Tpng > controllers.png
  Controller diagram in PNG format
railroad -h
  Shows usage help

Processing DOT files

To produce a PNG image from model diagram generated by RailRoad you can issue the following command:

dot -Tpng models.dot > models.png

If you want to do the same with a controller diagram, use neato instead of dot:

neato -Tpng controllers.dot > controllers.png

If you want to produce SVG (vectorial, scalable, editable) files, you can do the following:

dot -Tsvg models.dot > models.svg
neato -Tsvg controllers.dot > controllers.svg

Important: There is a bug in Graphviz tools when generating SVG files that cause a text overflow. You can solve this problem editing (with a text editor, not a graphical SVG editor) the file and replacing around line 12 “font-size:14.00;” by “font-size:11.00;”, or by issuing the following command (see “man sed”):

sed -i 's/font-size:14.00/font-size:11.00/g' file.svg

Note: For viewing and editing SVG there is an excellent opensource tool called Inkscape (similar to Adobe Illustrator. For DOT processing you can also use Omnigraffle (on Mac OS X).

RailRoad as a rake task

(Thanks to Thomas Ritz, www.galaxy-ritz.de ,for the code.)

In your Rails application, put the following rake tasks into 'lib/task/diagrams.rake':

namespace :doc do
  namespace :diagram do
    task :models do
      sh "railroad -i -l -a -m -M | dot -Tsvg | sed 's/font-size:14.00/font-size:11.00/g' > doc/models.svg"

    task :controllers do
      sh "railroad -i -l -C | neato -Tsvg | sed 's/font-size:14.00/font-size:11.00/g' > doc/controllers.svg"

  task :diagrams => %w(diagram:models diagram:controllers)

Then, 'rake doc:diagrams' produces 'doc/models.svg' and 'doc/controllers.svg'.


RailRoad has been tested with Ruby 1.8.5 and Rails 1.1.6 to 1.2.3 applications. There is no additional requirements (nevertheless, all your Rails application requirements must be installed).

In order to view/export the DOT diagrams, you'll need the processing tools from Graphviz.

Website and Project Home



RailRoad is distributed under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.


Javier Smaldone (javier -at- smaldone -dot- com -dot- ar, blog.smaldone.com.ar )