diff --git a/railties/lib/rails/command/actions.rb b/railties/lib/rails/command/actions.rb
index 52d3348db37f99ae41b477dd1e1be2d64322b986..31b656ec31d068d64f8b78e5e3b0aec56d4f2c4d 100644
--- a/railties/lib/rails/command/actions.rb
+++ b/railties/lib/rails/command/actions.rb
@@ -1,18 +1,42 @@
 module Rails
   module Command
     module Actions
-      private
-        # Change to the application's path if there is no config.ru file in current directory.
-        # This allows us to run `rails server` from other directories, but still get
-        # the main config.ru and properly set the tmp directory.
-        def set_application_directory!
-          Dir.chdir(File.expand_path("../../", APP_PATH)) unless File.exist?(File.expand_path("config.ru"))
+      # Change to the application's path if there is no config.ru file in current directory.
+      # This allows us to run `rails server` from other directories, but still get
+      # the main config.ru and properly set the tmp directory.
+      def set_application_directory!
+        Dir.chdir(File.expand_path("../../", APP_PATH)) unless File.exist?(File.expand_path("config.ru"))
+      end
+
+      if defined?(ENGINE_PATH)
+        def require_application_and_environment!
+          require ENGINE_PATH
         end
 
+        def load_tasks
+          Rake.application.init("rails")
+          Rake.application.load_rakefile
+        end
+
+        def load_generators
+          engine = ::Rails::Engine.find(ENGINE_ROOT)
+          Rails::Generators.namespace = engine.railtie_namespace
+          engine.load_generators
+        end
+      else
         def require_application_and_environment!
           require APP_PATH
           Rails.application.require_environment!
         end
+
+        def load_tasks
+          Rails.application.load_tasks
+        end
+
+        def load_generators
+          Rails.application.load_generators
+        end
+      end
     end
   end
 end
diff --git a/railties/lib/rails/command/base.rb b/railties/lib/rails/command/base.rb
index 2ef8393863efc8d3a4c5fd43e385283c0f775bc9..73ebaca66f6cd6c7dac2a67602ea27c8b1d7d0b5 100644
--- a/railties/lib/rails/command/base.rb
+++ b/railties/lib/rails/command/base.rb
@@ -15,6 +15,11 @@ class Error < Thor::Error # :nodoc:
       include Actions
 
       class << self
+        # Returns true when the app is a Rails engine.
+        def engine?
+          defined?(ENGINE_ROOT)
+        end
+
         # Tries to get the description from a USAGE file one folder above the command
         # root.
         def desc(usage = nil, description = nil)
diff --git a/railties/lib/rails/commands/help/USAGE b/railties/lib/rails/commands/help/USAGE
index 0f6ff756ceb42d96491ff265a8e5928c1ae85e71..348f41861f8342bed42ae04810fdc91a4702a1de 100644
--- a/railties/lib/rails/commands/help/USAGE
+++ b/railties/lib/rails/commands/help/USAGE
@@ -1,5 +1,16 @@
 Usage: bin/rails COMMAND [args] [options]
+<% if engine? %>
+The common Rails commands available for engines are:
+ generate    Generate new code (short-cut alias: "g")
+ destroy     Undo code generated with "generate" (short-cut alias: "d")
+ test        Run tests (short-cut alias: "t")
 
+All commands can be run with -h for more information.
+
+If you want to run any commands that need to be run in context
+of the application, like `bin/rails server` or `bin/rails console`,
+you should do it from the application's directory (typically test/dummy).
+<% else %>
 The most common rails commands are:
  generate    Generate new code (short-cut alias: "g")
  console     Start the Rails console (short-cut alias: "c")
@@ -11,6 +22,6 @@ The most common rails commands are:
              new application called MyApp in "./my_app"
 
 All commands can be run with -h (or --help) for more information.
-
+<% end %>
 In addition to those commands, there are:
 
diff --git a/railties/lib/rails/commands/rake/rake_command.rb b/railties/lib/rails/commands/rake/rake_command.rb
index a4a2464445c4004d97c9d88c7b009a0b62ba0776..a43c884170d5cf18790d249cbb25afcb95bb4017 100644
--- a/railties/lib/rails/commands/rake/rake_command.rb
+++ b/railties/lib/rails/commands/rake/rake_command.rb
@@ -1,6 +1,8 @@
 module Rails
   module Command
     class RakeCommand < Base
+      extend Rails::Command::Actions
+
       namespace "rake"
 
       class << self
@@ -27,12 +29,12 @@ def rake_tasks
             return @rake_tasks if defined?(@rake_tasks)
 
             ActiveSupport::Deprecation.silence do
-              Rails::Command.require_application_and_environment!
+              require_application_and_environment!
             end
 
             Rake::TaskManager.record_task_metadata = true
             Rake.application.instance_variable_set(:@name, "rails")
-            Rails.application.load_tasks
+            load_tasks
             @rake_tasks = Rake.application.tasks.select(&:comment)
           end
 
diff --git a/railties/lib/rails/engine/commands.rb b/railties/lib/rails/engine/commands.rb
index dfbeea36b85178e3669872c469f7ca25ca78a15a..a23ae44b0bf1c1fcd3d8cdc4dece6ed3a69d03cc 100644
--- a/railties/lib/rails/engine/commands.rb
+++ b/railties/lib/rails/engine/commands.rb
@@ -1,6 +1,4 @@
-require "rails/engine/commands_tasks"
-
-ARGV << "--help" if ARGV.empty?
+require "rails/command"
 
 aliases = {
   "g" => "generate",
@@ -11,4 +9,4 @@
 command = ARGV.shift
 command = aliases[command] || command
 
-Rails::Engine::CommandsTasks.new(ARGV).run_command!(command)
+Rails::Command.invoke command, ARGV
diff --git a/railties/lib/rails/engine/commands_tasks.rb b/railties/lib/rails/engine/commands_tasks.rb
index d6effdb732c96d7a0d22b6ff547bef84f93ce093..65dd27479371ad0f5352c50e9dc217929dffe26f 100644
--- a/railties/lib/rails/engine/commands_tasks.rb
+++ b/railties/lib/rails/engine/commands_tasks.rb
@@ -26,7 +26,7 @@ def command_whitelist
 
         def help_message
           <<-EOT.strip_heredoc
-            Usage: rails COMMAND [ARGS]
+            Usage: bin/rails COMMAND [ARGS]
 
             The common Rails commands available for engines are:
              generate    Generate new code (short-cut alias: "g")