diff --git a/actionpack/lib/action_dispatch.rb b/actionpack/lib/action_dispatch.rb
index dfb8919561727..cdf81c6648150 100644
--- a/actionpack/lib/action_dispatch.rb
+++ b/actionpack/lib/action_dispatch.rb
@@ -43,7 +43,6 @@ module ActionDispatch
 
   autoload_under 'middleware' do
     autoload :Callbacks
-    autoload :Cascade
     autoload :Cookies
     autoload :Flash
     autoload :Head
diff --git a/actionpack/lib/action_dispatch/middleware/cascade.rb b/actionpack/lib/action_dispatch/middleware/cascade.rb
deleted file mode 100644
index 9f5c9891f0f5c..0000000000000
--- a/actionpack/lib/action_dispatch/middleware/cascade.rb
+++ /dev/null
@@ -1,29 +0,0 @@
-module ActionDispatch
-  class Cascade
-    def self.new(*apps)
-      apps = apps.flatten
-
-      case apps.length
-      when 0
-        raise ArgumentError, "app is required"
-      when 1
-        apps.first
-      else
-        super(apps)
-      end
-    end
-
-    def initialize(apps)
-      @apps = apps
-    end
-
-    def call(env)
-      result = nil
-      @apps.each do |app|
-        result = app.call(env)
-        break unless result[1]["X-Cascade"] == "pass"
-      end
-      result
-    end
-  end
-end
diff --git a/railties/guides/source/configuring.textile b/railties/guides/source/configuring.textile
index bd2289890ab12..ab72b48034122 100644
--- a/railties/guides/source/configuring.textile
+++ b/railties/guides/source/configuring.textile
@@ -63,8 +63,6 @@ h4. Rails General Configuration
 
 * +config.logger+ accepts a logger conforming to the interface of Log4r or the default Ruby 1.8+ Logger class, which is then used to log information from Action Controller. Set to nil to disable logging.
 
-* +config.metals+ accepts an array used as the metals to load. If this is set to nil, all metals will be loaded in alphabetical order. If this is set to [], no metals will be loaded. Otherwise metals will be loaded in the order specified 
-
 * +config.plugin_loader+ overrides the class that handles loading each plugin. Defaults to +Rails::Plugin::Loader+.
 
 * +config.plugin_locators+ overrides the class that handle finding the desired plugins that you‘d like to load for your application. By default it is the +Rails::Plugin::FileSystemLocator+.
diff --git a/railties/guides/source/initialization.textile b/railties/guides/source/initialization.textile
index cccbb9df06775..58ae115ba79bb 100644
--- a/railties/guides/source/initialization.textile
+++ b/railties/guides/source/initialization.textile
@@ -668,7 +668,6 @@ This file requires _rails/railtie.rb_ which defines +Rails::Railtie+.
 * add_routing_namespaces
 * add_locales
 * add_view_paths
-* add_metals
 * add_generator_templates
 * load_application_initializers
 * load_application_classes
@@ -726,7 +725,6 @@ This file is used to set up the +Rails::Paths+ module which is used to set up he
       paths.app.helpers         "app/helpers",         :eager_load => true
       paths.app.models          "app/models",          :eager_load => true
       paths.app.mailers         "app/mailers",         :eager_load => true
-      paths.app.metals          "app/metal",           :eager_load => true
       paths.app.views           "app/views",           :eager_load => true
       paths.lib                 "lib",                 :load_path => true
       paths.lib.tasks           "lib/tasks",           :glob => "**/*.rake"
@@ -3154,7 +3152,6 @@ This method is defined like this:
       middleware.use('ActionDispatch::Cookies')
       middleware.use(lambda { ActionController::Base.session_store }, lambda { ActionController::Base.session_options })
       middleware.use('ActionDispatch::Flash', :if => lambda { ActionController::Base.session_store })
-      middleware.use(lambda { Rails::Rack::Metal.new(Rails.application.config.paths.app.metals.to_a, Rails.application.config.metals) })
       middleware.use('ActionDispatch::ParamsParser')
       middleware.use('::Rack::MethodOverride')
       middleware.use('::ActionDispatch::Head')
@@ -3288,7 +3285,7 @@ Finally, a +Rails::Application::Configuration+ object will be returned. On this
 <ruby>
   attr_accessor :after_initialize_blocks, :cache_classes, :colorize_logging,
                 :consider_all_requests_local, :dependency_loading,
-                :load_once_paths, :logger, :metals, :plugins,
+                :load_once_paths, :logger, :plugins,
                 :preload_frameworks, :reload_plugins, :serve_static_assets,
                 :time_zone, :whiny_nils
 
@@ -3574,7 +3571,6 @@ The +super+ method it references comes from +Rails::Engine::Configuration+ which
       paths.app.controllers     "app/controllers",     :eager_load => true
       paths.app.helpers         "app/helpers",         :eager_load => true
       paths.app.models          "app/models",          :eager_load => true
-      paths.app.metals          "app/metal"
       paths.app.views           "app/views"
       paths.lib                 "lib",                 :load_path => true
       paths.lib.tasks           "lib/tasks",           :glob => "**/*.rake"
diff --git a/railties/guides/source/rails_on_rack.textile b/railties/guides/source/rails_on_rack.textile
index 512be43668c62..eaebb05f17273 100644
--- a/railties/guides/source/rails_on_rack.textile
+++ b/railties/guides/source/rails_on_rack.textile
@@ -222,57 +222,6 @@ use MyOwnStackFromStratch
 run ActionController::Dispatcher.new
 </ruby>
 
-h3. Rails Metal Applications
-
-Rails Metal applications are minimal Rack applications specially designed for integrating with a typical Rails application. As Rails Metal Applications skip all of the Action Controller stack, serving a request has no overhead from the Rails framework itself. This is especially useful for infrequent cases where the performance of the full stack Rails framework is an issue.
-
-Ryan Bates' "Railscast on Rails Metal":http://railscasts.com/episodes/150-rails-metal provides a nice walkthrough generating and using Rails Metal.
-
-h4. Generating a Metal Application
-
-Rails provides a generator called +metal+ for creating a new Metal application:
-
-<shell>
-$ rails generate metal poller
-</shell>
-
-This generates +poller.rb+ in the +app/metal+ directory:
-
-<ruby>
-# Allow the metal piece to run in isolation
-require(File.dirname(__FILE__) + "/../../config/environment") unless defined?(Rails)
-
-class Poller
-  def self.call(env)
-    if env["PATH_INFO"] =~ /^\/poller/
-      [200, {"Content-Type" => "text/html"}, ["Hello, World!"]]
-    else
-      [404, {"Content-Type" => "text/html", "X-Cascade" => "pass"}, ["Not Found"]]
-    end
-  end
-end
-</ruby>
-
-Metal applications within +app/metal+ folders in plugins will also be discovered and added to the list.
-
-Metal applications are an optimization. You should make sure to "understand the related performance implications":http://weblog.rubyonrails.org/2008/12/20/performance-of-rails-metal before using it.
-
-WARNING: To continue the Metal chain execution, return an +X-Cascade+ HTTP header with a value of +pass+.
-
-h4. Execution Order
-
-All Metal Applications are executed in alphabetical order of their filenames, so +aaa.rb+ will come before +bbb.rb+ in the metal chain.
-
-You can override the default ordering in your environment. Simply add a line like the following to +config/application.rb+
-
-It is, however, possible to override the default ordering in your environment. Simply add a line like the following to +config/environment.rb+
-
-<ruby>
-config.metals = ["Bbb", "Aaa"]
-</ruby>
-
-Each string in the array should be the name of your metal class. If you do this then be warned that any metal applications not listed will not be loaded.
-
 h3. Resources
 
 h4. Learning Rack
diff --git a/railties/lib/rails/application.rb b/railties/lib/rails/application.rb
index a3b3a56bc83b2..c588a4144371d 100644
--- a/railties/lib/rails/application.rb
+++ b/railties/lib/rails/application.rb
@@ -27,7 +27,7 @@ module Rails
   # Besides providing the same configuration as Rails::Engine and Rails::Railtie,
   # the application object has several specific configurations, for example
   # "allow_concurrency", "cache_classes", "consider_all_requests_local", "filter_parameters",
-  # "logger", "metals", "reload_engines", "reload_plugins" and so forth.
+  # "logger", "reload_engines", "reload_plugins" and so forth.
   #
   # Check Rails::Application::Configuration to see them all.
   #
@@ -36,17 +36,15 @@ module Rails
   # The application object is also responsible for holding the routes and reloading routes
   # whenever the files change in development.
   #
-  # == Middlewares and metals
+  # == Middlewares
   #
-  # The Application is also responsible for building the middleware stack and setting up
-  # both application and engines metals.
+  # The Application is also responsible for building the middleware stack.
   #
   class Application < Engine
     autoload :Bootstrap,      'rails/application/bootstrap'
     autoload :Configurable,   'rails/application/configurable'
     autoload :Configuration,  'rails/application/configuration'
     autoload :Finisher,       'rails/application/finisher'
-    autoload :MetalLoader,    'rails/application/metal_loader'
     autoload :Railties,       'rails/application/railties'
     autoload :RoutesReloader, 'rails/application/routes_reloader'
 
@@ -83,7 +81,7 @@ def method_missing(*args, &block)
       end
     end
 
-    delegate :middleware, :metal_loader, :to => :config
+    delegate :middleware, :to => :config
 
     def require_environment!
       environment = paths.config.environment.to_a.first
diff --git a/railties/lib/rails/application/configuration.rb b/railties/lib/rails/application/configuration.rb
index 1b8af370f765e..f3a326f36d954 100644
--- a/railties/lib/rails/application/configuration.rb
+++ b/railties/lib/rails/application/configuration.rb
@@ -9,7 +9,7 @@ class Configuration < ::Rails::Engine::Configuration
 
       attr_accessor :allow_concurrency, :cache_classes, :cache_store,
                     :encoding, :consider_all_requests_local, :dependency_loading,
-                    :filter_parameters,  :log_level, :logger, :metals,
+                    :filter_parameters,  :log_level, :logger,
                     :plugins, :preload_frameworks, :reload_engines, :reload_plugins,
                     :secret_token, :serve_static_assets, :session_options,
                     :time_zone, :whiny_nils
@@ -45,10 +45,6 @@ def middleware
         @middleware ||= app_middleware.merge_into(default_middleware_stack)
       end
 
-      def metal_loader
-        @metal_loader ||= Rails::Application::MetalLoader.new
-      end
-
       def paths
         @paths ||= begin
           paths = super
@@ -157,7 +153,6 @@ def default_middleware_stack
           middleware.use('::ActionDispatch::ParamsParser')
           middleware.use('::Rack::MethodOverride')
           middleware.use('::ActionDispatch::Head')
-          middleware.use(lambda { metal_loader.build_middleware(metals) }, :if => lambda { metal_loader.metals.any? })
         end
       end
     end
diff --git a/railties/lib/rails/application/metal_loader.rb b/railties/lib/rails/application/metal_loader.rb
deleted file mode 100644
index 2a43fa7892ff4..0000000000000
--- a/railties/lib/rails/application/metal_loader.rb
+++ /dev/null
@@ -1,50 +0,0 @@
-require 'action_dispatch'
-
-module Rails
-  class Application
-    class MetalLoader
-      attr_reader :paths, :metals
-
-      def initialize
-        @paths, @metals = [], []
-      end
-
-      def build_middleware(list=nil)
-        load_metals!(list)
-        self
-      end
-
-      def new(app)
-        ActionDispatch::Cascade.new(@metals, app)
-      end
-
-      def name
-        ActionDispatch::Cascade.name
-      end
-      alias :to_s :name
-
-    protected
-
-      def load_metals!(list)
-        metals = []
-        list = Array(list || :all).map(&:to_sym)
-
-        paths.each do |path|
-          matcher = /\A#{Regexp.escape(path)}\/(.*)\.rb\Z/
-          Dir.glob("#{path}/**/*.rb").sort.each do |metal_path|
-            metal = metal_path.sub(matcher, '\1').to_sym
-            next unless list.include?(metal) || list.include?(:all)
-            require_dependency metal.to_s
-            metals << metal
-          end
-        end
-
-        metals = metals.sort_by do |m|
-          [list.index(m) || list.index(:all), m.to_s]
-        end
-
-        @metals = metals.map { |m| m.to_s.camelize.constantize }
-      end
-    end
-  end
-end
diff --git a/railties/lib/rails/engine.rb b/railties/lib/rails/engine.rb
index b44755820c8e3..cdb00a4eff554 100644
--- a/railties/lib/rails/engine.rb
+++ b/railties/lib/rails/engine.rb
@@ -25,7 +25,7 @@ module Rails
   #   end
   #
   # Then ensure that this file is loaded at the top of your config/application.rb (or in
-  # your Gemfile) and it will automatically load models, controllers, helpers and metals
+  # your Gemfile) and it will automatically load models, controllers and helpers
   # inside app, load routes at "config/routes.rb", load locales at "config/locales/*",
   # load tasks at "lib/tasks/*".
   #
@@ -73,7 +73,6 @@ module Rails
   #     paths.app.controllers     = "app/controllers"
   #     paths.app.helpers         = "app/helpers"
   #     paths.app.models          = "app/models"
-  #     paths.app.metals          = "app/metal"
   #     paths.app.views           = "app/views"
   #     paths.lib                 = "lib"
   #     paths.lib.tasks           = "lib/tasks"
@@ -202,10 +201,6 @@ def eager_load!
       end
     end
 
-    initializer :add_metals do |app|
-      app.metal_loader.paths.unshift(*paths.app.metals.to_a)
-    end
-
     initializer :load_config_initializers do
       paths.config.initializers.to_a.sort.each do |initializer|
         load(initializer)
diff --git a/railties/lib/rails/engine/configuration.rb b/railties/lib/rails/engine/configuration.rb
index c5411a0331ddc..446fe0bda9ad7 100644
--- a/railties/lib/rails/engine/configuration.rb
+++ b/railties/lib/rails/engine/configuration.rb
@@ -19,7 +19,6 @@ def paths
           paths.app.helpers         "app/helpers",         :eager_load => true
           paths.app.models          "app/models",          :eager_load => true
           paths.app.mailers         "app/mailers",         :eager_load => true
-          paths.app.metals          "app/metal",           :eager_load => true
           paths.app.views           "app/views"
           paths.lib                 "lib",                 :load_path => true
           paths.lib.tasks           "lib/tasks",           :glob => "**/*.rake"
diff --git a/railties/lib/rails/generators/base.rb b/railties/lib/rails/generators/base.rb
index 766644bbc23a4..bd2260fc2991a 100644
--- a/railties/lib/rails/generators/base.rb
+++ b/railties/lib/rails/generators/base.rb
@@ -288,7 +288,7 @@ def self.base_name
         end
 
         # Removes the namespaces and get the generator name. For example,
-        # Rails::Generators::MetalGenerator will return "metal" as generator name.
+        # Rails::Generators::ModelGenerator will return "model" as generator name.
         #
         def self.generator_name
           @generator_name ||= begin
diff --git a/railties/lib/rails/generators/rails/metal/USAGE b/railties/lib/rails/generators/rails/metal/USAGE
deleted file mode 100644
index c88325a4441be..0000000000000
--- a/railties/lib/rails/generators/rails/metal/USAGE
+++ /dev/null
@@ -1,8 +0,0 @@
-Description:
-    Cast some metal!
-
-Examples:
-    `rails generate metal poller`
-
-        This will create:
-            Metal: app/metal/poller.rb
diff --git a/railties/lib/rails/generators/rails/metal/metal_generator.rb b/railties/lib/rails/generators/rails/metal/metal_generator.rb
deleted file mode 100644
index fe4f945cad5d1..0000000000000
--- a/railties/lib/rails/generators/rails/metal/metal_generator.rb
+++ /dev/null
@@ -1,11 +0,0 @@
-module Rails
-  module Generators
-    class MetalGenerator < NamedBase
-      check_class_collision
-
-      def create_metal_file
-        template "metal.rb", "app/metal/#{file_name}.rb"
-      end
-    end
-  end
-end
diff --git a/railties/lib/rails/generators/rails/metal/templates/metal.rb b/railties/lib/rails/generators/rails/metal/templates/metal.rb
deleted file mode 100644
index 8cc3f1f258a7f..0000000000000
--- a/railties/lib/rails/generators/rails/metal/templates/metal.rb
+++ /dev/null
@@ -1,12 +0,0 @@
-# Allow the metal piece to run in isolation
-require File.expand_path('../../../config/environment',  __FILE__) unless defined?(Rails)
-
-class <%= class_name %>
-  def self.call(env)
-    if env["PATH_INFO"] =~ /^\/<%= file_name %>/
-      [200, {"Content-Type" => "text/html"}, ["Hello, World!"]]
-    else
-      [404, {"Content-Type" => "text/html", "X-Cascade" => "pass"}, ["Not Found"]]
-    end
-  end
-end
diff --git a/railties/lib/rails/tasks/framework.rake b/railties/lib/rails/tasks/framework.rake
index 063a393bfcdc5..ac510eee2e6b4 100644
--- a/railties/lib/rails/tasks/framework.rake
+++ b/railties/lib/rails/tasks/framework.rake
@@ -37,7 +37,7 @@ namespace :rails do
       project_templates = "#{Rails.root}/lib/templates"
 
       default_templates = { "erb"   => %w{controller mailer scaffold},
-                            "rails" => %w{controller helper metal scaffold_controller stylesheets} }
+                            "rails" => %w{controller helper scaffold_controller stylesheets} }
 
       default_templates.each do |type, names|
         local_template_type_dir = File.join(project_templates, type)
diff --git a/railties/test/application/metal_test.rb b/railties/test/application/metal_test.rb
deleted file mode 100644
index 1ec62282c85d4..0000000000000
--- a/railties/test/application/metal_test.rb
+++ /dev/null
@@ -1,86 +0,0 @@
-require 'isolation/abstract_unit'
-
-module ApplicationTests
-  class MetalTest < Test::Unit::TestCase
-    include ActiveSupport::Testing::Isolation
-
-    def setup
-      build_app
-      boot_rails
-
-      require 'rack/test'
-      extend Rack::Test::Methods
-    end
-
-    def app
-      @app ||= begin
-        require "#{app_path}/config/environment"
-        Rails.application
-      end
-    end
-
-    test "single metal endpoint" do
-      app_file 'app/metal/foo_metal.rb', <<-RUBY
-        class FooMetal
-          def self.call(env)
-            [200, { "Content-Type" => "text/html"}, ["FooMetal"]]
-          end
-        end
-      RUBY
-
-      get "/not/slash"
-      assert_equal 200, last_response.status
-      assert_equal "FooMetal", last_response.body
-    end
-
-    test "multiple metal endpoints" do
-      app_file 'app/metal/metal_a.rb', <<-RUBY
-        class MetalA
-          def self.call(env)
-            [404, { "Content-Type" => "text/html", "X-Cascade" => "pass" }, ["Metal A"]]
-          end
-        end
-      RUBY
-
-      app_file 'app/metal/metal_b.rb', <<-RUBY
-        class MetalB
-          def self.call(env)
-            [200, { "Content-Type" => "text/html"}, ["Metal B"]]
-          end
-        end
-      RUBY
-
-      get "/not/slash"
-      assert_equal 200, last_response.status
-      assert_equal "Metal B", last_response.body
-    end
-
-    test "pass through to application" do
-      app_file 'app/metal/foo_metal.rb', <<-RUBY
-        class FooMetal
-          def self.call(env)
-            [404, { "Content-Type" => "text/html", "X-Cascade" => "pass" }, ["Not Found"]]
-          end
-        end
-      RUBY
-
-      controller :foo, <<-RUBY
-        class FooController < ActionController::Base
-          def index
-            render :text => "foo"
-          end
-        end
-      RUBY
-
-      app_file 'config/routes.rb', <<-RUBY
-        AppTemplate::Application.routes.draw do |map|
-          match ':controller(/:action)'
-        end
-      RUBY
-
-      get "/foo"
-      assert_equal 200, last_response.status
-      assert_equal "foo", last_response.body
-    end
-  end
-end
diff --git a/railties/test/application/middleware_test.rb b/railties/test/application/middleware_test.rb
index 617525bf78230..78e7c39660164 100644
--- a/railties/test/application/middleware_test.rb
+++ b/railties/test/application/middleware_test.rb
@@ -82,12 +82,6 @@ def app
       assert_equal "Rack::Config", middleware.first
     end
 
-    test "shows cascade if any metal exists" do
-      app_file "app/metal/foo.rb", "class Foo; end"
-      boot!
-      assert middleware.include?("ActionDispatch::Cascade")
-    end
-
     # x_sendfile_header middleware
     test "config.action_dispatch.x_sendfile_header defaults to ''" do
       make_basic_app
diff --git a/railties/test/application/paths_test.rb b/railties/test/application/paths_test.rb
index 978d677efc36d..c98b11556b69c 100644
--- a/railties/test/application/paths_test.rb
+++ b/railties/test/application/paths_test.rb
@@ -38,7 +38,6 @@ def assert_not_in_load_path(*path)
 
     test "booting up Rails yields a valid paths object" do
       assert_path @paths.app.models, "app", "models"
-      assert_path @paths.app.metals, "app", "metal"
       assert_path @paths.app.helpers, "app", "helpers"
       assert_path @paths.app.views, "app", "views"
       assert_path @paths.lib, "lib"
@@ -73,7 +72,6 @@ def assert_not_in_load_path(*path)
       assert_in_load_path "vendor"
 
       assert_not_in_load_path "app", "views"
-      assert_not_in_load_path "app", "metal"
       assert_not_in_load_path "config"
       assert_not_in_load_path "config", "locales"
       assert_not_in_load_path "config", "environments"
diff --git a/railties/test/generators/metal_generator_test.rb b/railties/test/generators/metal_generator_test.rb
deleted file mode 100644
index 615122c882c60..0000000000000
--- a/railties/test/generators/metal_generator_test.rb
+++ /dev/null
@@ -1,17 +0,0 @@
-require 'generators/generators_test_helper'
-require 'rails/generators/rails/metal/metal_generator'
-
-class MetalGeneratorTest < Rails::Generators::TestCase
-  include GeneratorsTestHelper
-  arguments %w(foo)
-
-  def test_metal_skeleton_is_created
-    run_generator
-    assert_file "app/metal/foo.rb", /class Foo/
-  end
-
-  def test_check_class_collision
-    content = capture(:stderr){ run_generator ["object"] }
-    assert_match /The name 'Object' is either already used in your application or reserved/, content
-  end
-end
diff --git a/railties/test/railties/shared_tests.rb b/railties/test/railties/shared_tests.rb
index 20328d402d85b..3f78d7d3fe052 100644
--- a/railties/test/railties/shared_tests.rb
+++ b/railties/test/railties/shared_tests.rb
@@ -241,24 +241,6 @@ def test_i18n_files_have_lower_priority_than_application_ones
       assert_equal "1", I18n.t(:bar)
     end
 
-    def test_plugin_metals_added_to_middleware_stack
-      @plugin.write 'app/metal/foo_metal.rb', <<-RUBY
-        class FooMetal
-          def self.call(env)
-            [200, { "Content-Type" => "text/html"}, ["FooMetal"]]
-          end
-        end
-      RUBY
-
-      boot_rails
-      require 'rack/test'
-      extend Rack::Test::Methods
-
-      get "/not/slash"
-      assert_equal 200, last_response.status
-      assert_equal "FooMetal", last_response.body
-    end
-
     def test_namespaced_controllers_with_namespaced_routes
       @plugin.write "config/routes.rb", <<-RUBY
         Rails.application.routes.draw do