diff --git a/activerecord/lib/active_record/railtie.rb b/activerecord/lib/active_record/railtie.rb
index 898df0a67a0a88a39bc355217127b365e8377829..a32fb7d399f89adcb98c8cd5ee1700345df004da 100644
--- a/activerecord/lib/active_record/railtie.rb
+++ b/activerecord/lib/active_record/railtie.rb
@@ -15,6 +15,12 @@ class Railtie < Rails::Railtie
     config.generators.orm :active_record, :migration => true,
                                           :timestamps => true
 
+    config.app_middleware.insert_after "::ActionDispatch::Callbacks",
+      "ActiveRecord::QueryCache"
+
+    config.app_middleware.insert_after "::ActionDispatch::Callbacks",
+      "ActiveRecord::ConnectionAdapters::ConnectionManagement"
+
     rake_tasks do
       load "active_record/railties/databases.rake"
     end
@@ -58,16 +64,9 @@ class Railtie < Rails::Railtie
       end
     end
 
-    # Setup database middleware after initializers have run
-    initializer "active_record.initialize_database_middleware", :after => "action_controller.set_configs" do |app|
-      middleware = app.config.middleware
-      middleware.insert_after "::ActionDispatch::Callbacks", ActiveRecord::QueryCache
-      middleware.insert_after "::ActionDispatch::Callbacks", ActiveRecord::ConnectionAdapters::ConnectionManagement
-    end
-
     initializer "active_record.set_dispatch_hooks", :before => :set_clear_dependencies_hook do |app|
-      ActiveSupport.on_load(:active_record) do
-        unless app.config.cache_classes
+      unless app.config.cache_classes
+        ActiveSupport.on_load(:active_record) do
           ActionDispatch::Callbacks.after do
             ActiveRecord::Base.reset_subclasses
             ActiveRecord::Base.clear_reloadable_connections!
diff --git a/activesupport/lib/active_support/lazy_load_hooks.rb b/activesupport/lib/active_support/lazy_load_hooks.rb
index 642a4c105c8f87d213a203f191cb0e62dabcf5a7..3664431a2800cb855f6c0801c02b5a35786784f2 100644
--- a/activesupport/lib/active_support/lazy_load_hooks.rb
+++ b/activesupport/lib/active_support/lazy_load_hooks.rb
@@ -2,16 +2,26 @@ module ActiveSupport
   @load_hooks = Hash.new {|h,k| h[k] = [] }
   @loaded = {}
 
-  def self.on_load(name, &block)
+  def self.on_load(name, options = {}, &block)
     if base = @loaded[name]
-      base.instance_eval(&block)
+      execute_hook(base, options, block)
     else
-      @load_hooks[name] << block
+      @load_hooks[name] << [block, options]
+    end
+  end
+
+  def self.execute_hook(base, options, block)
+    if options[:yield]
+      block.call(base)
+    else
+      base.instance_eval(&block)
     end
   end
 
   def self.run_load_hooks(name, base = Object)
-    @load_hooks[name].each { |hook| base.instance_eval(&hook) }
     @loaded[name] = base
+    @load_hooks[name].each do |hook, options|
+      execute_hook(base, options, hook)
+    end
   end
 end
\ No newline at end of file
diff --git a/activesupport/test/lazy_load_hooks_test.rb b/activesupport/test/lazy_load_hooks_test.rb
new file mode 100644
index 0000000000000000000000000000000000000000..58ccc143241bc1d3a5673301cdaa840450c93b0f
--- /dev/null
+++ b/activesupport/test/lazy_load_hooks_test.rb
@@ -0,0 +1,67 @@
+require 'abstract_unit'
+
+class LazyLoadHooksTest < ActiveSupport::TestCase
+  def test_basic_hook
+    i = 0
+    ActiveSupport.on_load(:basic_hook) { i += 1 }
+    ActiveSupport.run_load_hooks(:basic_hook)
+    assert_equal 1, i
+  end
+
+  def test_hook_registered_after_run
+    i = 0
+    ActiveSupport.run_load_hooks(:registered_after)
+    assert_equal 0, i
+    ActiveSupport.on_load(:registered_after) { i += 1 }
+    assert_equal 1, i
+  end
+
+  def test_hook_receives_a_context
+    i = 0
+    ActiveSupport.on_load(:contextual) { i += incr }
+    assert_equal 0, i
+    ActiveSupport.run_load_hooks(:contextual, FakeContext.new(2))
+    assert_equal 2, i
+  end
+
+  def test_hook_receives_a_context_afterward
+    i = 0
+    ActiveSupport.run_load_hooks(:contextual_after, FakeContext.new(2))
+    assert_equal 0, i
+    ActiveSupport.on_load(:contextual_after) { i += incr }
+    assert_equal 2, i
+  end
+
+  def test_hook_with_yield_true
+    i = 0
+    ActiveSupport.on_load(:contextual_yield, :yield => true) do |obj|
+      i += obj.incr + incr_amt
+    end
+    assert_equal 0, i
+    ActiveSupport.run_load_hooks(:contextual_yield, FakeContext.new(2))
+    assert_equal 7, i
+  end
+
+  def test_hook_with_yield_true_afterward
+    i = 0
+    ActiveSupport.run_load_hooks(:contextual_yield_after, FakeContext.new(2))
+    assert_equal 0, i
+    ActiveSupport.on_load(:contextual_yield_after, :yield => true) do |obj|
+      i += obj.incr + incr_amt
+    end
+    assert_equal 7, i
+  end
+
+private
+
+  def incr_amt
+    5
+  end
+
+  class FakeContext
+    attr_reader :incr
+    def initialize(incr)
+      @incr = incr
+    end
+  end
+end
\ No newline at end of file
diff --git a/railties/guides/source/initialization.textile b/railties/guides/source/initialization.textile
index 9ce27fa331edb54d906ac27144e7b1ec77435465..96d6998e1c9fe8df8190c7832791776d519c8746 100644
--- a/railties/guides/source/initialization.textile
+++ b/railties/guides/source/initialization.textile
@@ -2379,7 +2379,6 @@ Now that we've referenced that class, it will be required for us. You'll notice
 * initialize_subscriber
 * set_clear_dependencies_hook
 * initialize_dependency_mechanism
-* bootstrap_load_path
 
 These are all defined using the +initializer+ method:
 
@@ -2930,7 +2929,6 @@ With +@@autoloads+ being
 * initialize_subscriber
 * set_clear_dependencies_hook
 * initialize_dependency_mechanism
-* bootstrap_load_path
 
 h4. Active Support Initializers
 
diff --git a/railties/lib/rails/application.rb b/railties/lib/rails/application.rb
index d39f9a2ae9e0139607d9830da95180bc80ef4420..9e18dccf698128c3eb7241de6b84cbc5142100b3 100644
--- a/railties/lib/rails/application.rb
+++ b/railties/lib/rails/application.rb
@@ -12,7 +12,7 @@ module Rails
   # points to it.
   #
   # In other words, Rails::Application is Singleton and whenever you are accessing
-  # Rails::Application.config or YourApplication::Application.config, you are actually 
+  # Rails::Application.config or YourApplication::Application.config, you are actually
   # accessing YourApplication::Application.instance.config.
   #
   # == Initialization
@@ -40,7 +40,7 @@ module Rails
   #
   # The Application is also responsible for building the middleware stack and setting up
   # both application and engines metals.
-  # 
+  #
   class Application < Engine
     autoload :Bootstrap,      'rails/application/bootstrap'
     autoload :Configurable,   'rails/application/configurable'
@@ -69,6 +69,8 @@ def inherited(base)
         raise "You cannot have more than one Rails::Application" if Rails.application
         super
         Rails.application = base.instance
+
+        ActiveSupport.run_load_hooks(:before_configuration, base.instance)
       end
 
       def respond_to?(*args)
@@ -82,7 +84,7 @@ def method_missing(*args, &block)
       end
     end
 
-    delegate :metal_loader, :to => :config
+    delegate :middleware, :metal_loader, :to => :config
 
     def require_environment!
       environment = paths.config.environment.to_a.first
@@ -125,7 +127,7 @@ def load_generators
     end
 
     def app
-      @app ||= middleware.build(routes)
+      @app ||= config.middleware.build(routes)
     end
 
     def call(env)
diff --git a/railties/lib/rails/application/bootstrap.rb b/railties/lib/rails/application/bootstrap.rb
index 022e1a91d8d50e063331298db8f40724e6897dec..e62eed8a8721bf2b05d6bd7c0eb1ccfc733dc4ef 100644
--- a/railties/lib/rails/application/bootstrap.rb
+++ b/railties/lib/rails/application/bootstrap.rb
@@ -10,7 +10,8 @@ module Bootstrap
         require environment if environment
       end
 
-      initializer :load_all_active_support do
+      initializer :load_active_support do
+        require 'active_support/dependencies'
         require "active_support/all" unless config.active_support.bare
       end
 
@@ -18,7 +19,6 @@ module Bootstrap
       # Used by Passenger to ensure everything's loaded before forking and
       # to avoid autoload race conditions in JRuby.
       initializer :preload_frameworks do
-        require 'active_support/dependencies'
         ActiveSupport::Autoload.eager_autoload! if config.preload_frameworks
       end
 
@@ -66,8 +66,8 @@ module Bootstrap
         ActiveSupport::Dependencies.mechanism = config.cache_classes ? :require : :load
       end
 
-      initializer :bootstrap_load_path do
-        # This is just an initializer used as hook so all load paths are loaded together
+      initializer :bootstrap_hook do |app|
+        ActiveSupport.run_load_hooks(:before_initialize, app)
       end
     end
   end
diff --git a/railties/lib/rails/application/configuration.rb b/railties/lib/rails/application/configuration.rb
index 1ad77fdfec76bbc026cf75039a7bb38a1312df02..cd77f1adaf8d65e6e4acb6e1082f9a2cb2cfcfce 100644
--- a/railties/lib/rails/application/configuration.rb
+++ b/railties/lib/rails/application/configuration.rb
@@ -33,7 +33,7 @@ def encoding=(value)
       end
 
       def middleware
-        @middleware ||= default_middleware_stack
+        @middleware ||= app_middleware.merge_into(default_middleware_stack)
       end
 
       def metal_loader
diff --git a/railties/lib/rails/application/finisher.rb b/railties/lib/rails/application/finisher.rb
index 94507bb3875db0b1c3938b3726bf1fdbcb92688d..03bc270c81ba75fa0f124711dbfe647f67e73989 100644
--- a/railties/lib/rails/application/finisher.rb
+++ b/railties/lib/rails/application/finisher.rb
@@ -35,10 +35,8 @@ module Finisher
         app
       end
 
-      initializer :after_initialize do
-        config.after_initialize_blocks.each do |block|
-          block.call(self)
-        end
+      initializer :finisher_hook do |app|
+        ActiveSupport.run_load_hooks(:after_initialize, app)
       end
 
       # Disable dependency loading during request cycle
diff --git a/railties/lib/rails/engine.rb b/railties/lib/rails/engine.rb
index ab0ead65a914b4f61e711991293eb8510b9aaa59..652bd40ee41ac0e52405b0f8cd4abe5f421788e4 100644
--- a/railties/lib/rails/engine.rb
+++ b/railties/lib/rails/engine.rb
@@ -45,7 +45,7 @@ module Rails
   #       app.middleware.use MyEngine::Middleware
   #     end
   #   end
-  # 
+  #
   # == Paths
   #
   # Since Rails 3.0, both your Application and Engines do not have hardcoded paths.
@@ -125,7 +125,7 @@ def find_root_with_flag(flag, default=nil)
       end
     end
 
-    delegate :middleware, :paths, :root, :to => :config
+    delegate :paths, :root, :to => :config
 
     def load_tasks
       super
@@ -133,7 +133,7 @@ def load_tasks
     end
 
     # Add configured load paths to ruby load paths and remove duplicates.
-    initializer :set_load_path, :before => :bootstrap_load_path do
+    initializer :set_load_path, :before => :bootstrap_hook do
       config.load_paths.reverse_each do |path|
         $LOAD_PATH.unshift(path) if File.directory?(path)
       end
@@ -142,7 +142,10 @@ def load_tasks
 
     # Set the paths from which Rails will automatically load source files,
     # and the load_once paths.
-    initializer :set_autoload_paths, :before => :bootstrap_load_path do |app|
+    #
+    # This needs to be an initializer, since it needs to run once
+    # per engine and get the engine as a block parameter
+    initializer :set_autoload_paths, :before => :bootstrap_hook do |app|
       ActiveSupport::Dependencies.load_paths.unshift(*config.load_paths)
 
       if reloadable?(app)
@@ -200,7 +203,9 @@ def load_tasks
       end
     end
 
-    initializer :load_app_classes do |app|
+    # This needs to be an initializer, since it needs to run once
+    # per engine and get the engine as a block parameter
+    initializer :load_app_classes, :before => :finisher_hook do |app|
       next if $rails_rake_task
 
       if app.config.cache_classes
diff --git a/railties/lib/rails/railtie/configuration.rb b/railties/lib/rails/railtie/configuration.rb
index 16eccaccc4486082baf42ee3644610f81dab3466..f57d82a3d88819ed1b3848c7c8bb9e7d6b4254ca 100644
--- a/railties/lib/rails/railtie/configuration.rb
+++ b/railties/lib/rails/railtie/configuration.rb
@@ -3,10 +3,50 @@
 module Rails
   class Railtie
     class Configuration
+      class MiddlewareStackProxy
+        def initialize
+          @operations = []
+        end
+
+        def insert_before(*args, &block)
+          @operations << [:insert_before, args, block]
+        end
+
+        alias insert insert_before
+
+        def insert_after(*args, &block)
+          @operations << [:insert_after, args, block]
+        end
+
+        def swap(*args, &block)
+          @operations << [:swap, args, block]
+        end
+
+        def use(*args, &block)
+          @operations << [:use, args, block]
+        end
+
+        def merge_into(other)
+          @operations.each do |operation, args, block|
+            other.send(operation, *args, &block)
+          end
+          other
+        end
+      end
+
       def initialize
         @@options ||= {}
       end
 
+      # This allows you to modify the application's middlewares from Engines.
+      #
+      # All operations you run on the app_middleware will be replayed on the
+      # application once it is defined and the default_middlewares are
+      # created
+      def app_middleware
+        @@app_middleware ||= MiddlewareStackProxy.new
+      end
+
       # Holds generators configuration:
       #
       #   config.generators do |g|
@@ -28,12 +68,8 @@ def generators
         end
       end
 
-      def after_initialize_blocks
-        @@after_initialize_blocks ||= []
-      end
-
-      def after_initialize(&blk)
-        after_initialize_blocks << blk if blk
+      def after_initialize(&block)
+        ActiveSupport.on_load(:after_initialize, :yield => true, &block)
       end
 
       def to_prepare_blocks
diff --git a/railties/test/application/initializers/initializers_test.rb b/railties/test/application/initializers/initializers_test.rb
index 2e6a707175198e44815f5d8be8ab8bf307235afd..eca42dada6425cbab33334842777bb3cf598a884 100644
--- a/railties/test/application/initializers/initializers_test.rb
+++ b/railties/test/application/initializers/initializers_test.rb
@@ -28,19 +28,6 @@ def setup
       assert_equal "congratulations", $test_after_initialize_block2
     end
 
-    test "after_initialize block works correctly when no block is passed" do
-      add_to_config <<-RUBY
-        config.root = "#{app_path}"
-        config.after_initialize { $test_after_initialize_block1 = "success" }
-        config.after_initialize # don't pass a block, this is what we're testing!
-        config.after_initialize { $test_after_initialize_block2 = "congratulations" }
-      RUBY
-      require "#{app_path}/config/environment"
-
-      assert_equal "success", $test_after_initialize_block1
-      assert_equal "congratulations", $test_after_initialize_block2
-    end
-
     test "after_initialize runs after frameworks have been initialized" do
       $activerecord_configurations = nil
       add_to_config <<-RUBY