2 files changed, 3 insertions, 3 deletions
diff --git a/railties/lib/rails/engine.rb b/railties/lib/rails/engine.rb
index 5c54cdaa70..5661094d95 100644
--- a/railties/lib/rails/engine.rb
+++ b/railties/lib/rails/engine.rb
@@ -371,7 +371,7 @@ module Rails
       end
 
       def isolate_namespace(mod)
-        engine_name(generate_railtie_name(mod))
+        engine_name(generate_railtie_name(mod.name))
 
         self.routes.default_scope = { module: ActiveSupport::Inflector.underscore(mod.name) }
         self.isolated = true
diff --git a/railties/lib/rails/railtie.rb b/railties/lib/rails/railtie.rb
index c63e0c0758..8d7e804bdc 100644
--- a/railties/lib/rails/railtie.rb
+++ b/railties/lib/rails/railtie.rb
@@ -183,8 +183,8 @@ module Rails
       end
 
       protected
-        def generate_railtie_name(class_or_module)
-          ActiveSupport::Inflector.underscore(class_or_module).tr("/", "_")
+        def generate_railtie_name(string)
+          ActiveSupport::Inflector.underscore(string).tr("/", "_")
         end
 
         # If the class method does not have a method, then send the method call