diff --git a/actionpack/lib/action_dispatch/journey.rb b/actionpack/lib/action_dispatch/journey.rb
index 2852efa6ae..18f966a640 100644
--- a/actionpack/lib/action_dispatch/journey.rb
+++ b/actionpack/lib/action_dispatch/journey.rb
@@ -3,5 +3,3 @@
 require "action_dispatch/journey/router"
 require "action_dispatch/journey/gtg/builder"
 require "action_dispatch/journey/gtg/simulator"
-require "action_dispatch/journey/nfa/builder"
-require "action_dispatch/journey/nfa/simulator"
diff --git a/actionpack/lib/action_dispatch/journey/nfa/builder.rb b/actionpack/lib/action_dispatch/journey/nfa/builder.rb
deleted file mode 100644
index d22302e101..0000000000
--- a/actionpack/lib/action_dispatch/journey/nfa/builder.rb
+++ /dev/null
@@ -1,78 +0,0 @@
-# frozen_string_literal: true
-
-require "action_dispatch/journey/nfa/transition_table"
-require "action_dispatch/journey/gtg/transition_table"
-
-module ActionDispatch
-  module Journey # :nodoc:
-    module NFA # :nodoc:
-      class Visitor < Visitors::Visitor # :nodoc:
-        def initialize(tt)
-          @tt = tt
-          @i  = -1
-        end
-
-        def visit_CAT(node)
-          left  = visit(node.left)
-          right = visit(node.right)
-
-          @tt.merge(left.last, right.first)
-
-          [left.first, right.last]
-        end
-
-        def visit_GROUP(node)
-          from  = @i += 1
-          left  = visit(node.left)
-          to    = @i += 1
-
-          @tt.accepting = to
-
-          @tt[from, left.first] = nil
-          @tt[left.last, to] = nil
-          @tt[from, to] = nil
-
-          [from, to]
-        end
-
-        def visit_OR(node)
-          from = @i += 1
-          children = node.children.map { |c| visit(c) }
-          to = @i += 1
-
-          children.each do |child|
-            @tt[from, child.first] = nil
-            @tt[child.last, to]    = nil
-          end
-
-          @tt.accepting = to
-
-          [from, to]
-        end
-
-        def terminal(node)
-          from_i = @i += 1 # new state
-          to_i   = @i += 1 # new state
-
-          @tt[from_i, to_i] = node
-          @tt.accepting = to_i
-          @tt.add_memo(to_i, node.memo)
-
-          [from_i, to_i]
-        end
-      end
-
-      class Builder # :nodoc:
-        def initialize(ast)
-          @ast = ast
-        end
-
-        def transition_table
-          tt = TransitionTable.new
-          Visitor.new(tt).accept(@ast)
-          tt
-        end
-      end
-    end
-  end
-end
diff --git a/actionpack/lib/action_dispatch/journey/nfa/dot.rb b/actionpack/lib/action_dispatch/journey/nfa/dot.rb
index 56e9e3c83d..48b56c8570 100644
--- a/actionpack/lib/action_dispatch/journey/nfa/dot.rb
+++ b/actionpack/lib/action_dispatch/journey/nfa/dot.rb
@@ -9,17 +9,6 @@ module ActionDispatch
             "  #{from} -> #{to} [label=\"#{sym || 'ε'}\"];"
           }
 
-          # memo_nodes = memos.values.flatten.map { |n|
-          #   label = n
-          #   if Journey::Route === n
-          #     label = "#{n.verb.source} #{n.path.spec}"
-          #   end
-          #   "  #{n.object_id} [label=\"#{label}\", shape=box];"
-          # }
-          # memo_edges = memos.flat_map { |k, memos|
-          #   (memos || []).map { |v| "  #{k} -> #{v.object_id};" }
-          # }.uniq
-
           <<-eodot
 digraph nfa {
   rankdir=LR;
diff --git a/actionpack/lib/action_dispatch/journey/nfa/simulator.rb b/actionpack/lib/action_dispatch/journey/nfa/simulator.rb
deleted file mode 100644
index 002f6feb97..0000000000
--- a/actionpack/lib/action_dispatch/journey/nfa/simulator.rb
+++ /dev/null
@@ -1,47 +0,0 @@
-# frozen_string_literal: true
-
-require "strscan"
-
-module ActionDispatch
-  module Journey # :nodoc:
-    module NFA # :nodoc:
-      class MatchData # :nodoc:
-        attr_reader :memos
-
-        def initialize(memos)
-          @memos = memos
-        end
-      end
-
-      class Simulator # :nodoc:
-        attr_reader :tt
-
-        def initialize(transition_table)
-          @tt = transition_table
-        end
-
-        def simulate(string)
-          input = StringScanner.new(string)
-          state = tt.eclosure(0)
-          until input.eos?
-            sym   = input.scan(%r([/.?]|[^/.?]+))
-            state = tt.eclosure(tt.move(state, sym))
-          end
-
-          acceptance_states = state.find_all { |s|
-            tt.accepting?(tt.eclosure(s).sort.last)
-          }
-
-          return if acceptance_states.empty?
-
-          memos = acceptance_states.flat_map { |x| tt.memo(x) }.compact
-
-          MatchData.new(memos)
-        end
-
-        alias :=~    :simulate
-        alias :match :simulate
-      end
-    end
-  end
-end
diff --git a/actionpack/lib/action_dispatch/journey/nfa/transition_table.rb b/actionpack/lib/action_dispatch/journey/nfa/transition_table.rb
deleted file mode 100644
index b36003089d..0000000000
--- a/actionpack/lib/action_dispatch/journey/nfa/transition_table.rb
+++ /dev/null
@@ -1,119 +0,0 @@
-# frozen_string_literal: true
-
-require "action_dispatch/journey/nfa/dot"
-
-module ActionDispatch
-  module Journey # :nodoc:
-    module NFA # :nodoc:
-      class TransitionTable # :nodoc:
-        include Journey::NFA::Dot
-
-        attr_accessor :accepting
-        attr_reader :memos
-
-        def initialize
-          @table     = Hash.new { |h, f| h[f] = {} }
-          @memos     = {}
-          @accepting = nil
-          @inverted  = nil
-        end
-
-        def accepting?(state)
-          accepting == state
-        end
-
-        def accepting_states
-          [accepting]
-        end
-
-        def add_memo(idx, memo)
-          @memos[idx] = memo
-        end
-
-        def memo(idx)
-          @memos[idx]
-        end
-
-        def []=(i, f, s)
-          @table[f][i] = s
-        end
-
-        def merge(left, right)
-          @memos[right] = @memos.delete(left)
-          @table[right] = @table.delete(left)
-        end
-
-        def states
-          (@table.keys + @table.values.flat_map(&:keys)).uniq
-        end
-
-        # Returns set of NFA states to which there is a transition on ast symbol
-        # +a+ from some state +s+ in +t+.
-        def following_states(t, a)
-          Array(t).flat_map { |s| inverted[s][a] }.uniq
-        end
-
-        # Returns set of NFA states to which there is a transition on ast symbol
-        # +a+ from some state +s+ in +t+.
-        def move(t, a)
-          Array(t).map { |s|
-            inverted[s].keys.compact.find_all { |sym|
-              sym === a
-            }.map { |sym| inverted[s][sym] }
-          }.flatten.uniq
-        end
-
-        def alphabet
-          inverted.values.flat_map(&:keys).compact.uniq.sort_by(&:to_s)
-        end
-
-        # Returns a set of NFA states reachable from some NFA state +s+ in set
-        # +t+ on nil-transitions alone.
-        def eclosure(t)
-          stack = Array(t)
-          seen  = {}
-          children = []
-
-          until stack.empty?
-            s = stack.pop
-            next if seen[s]
-
-            seen[s] = true
-            children << s
-
-            stack.concat(inverted[s][nil])
-          end
-
-          children.uniq
-        end
-
-        def transitions
-          @table.flat_map { |to, hash|
-            hash.map { |from, sym| [from, sym, to] }
-          }
-        end
-
-        private
-          def inverted
-            return @inverted if @inverted
-
-            @inverted = Hash.new { |h, from|
-              h[from] = Hash.new { |j, s| j[s] = [] }
-            }
-
-            @table.each { |to, hash|
-              hash.each { |from, sym|
-                if sym
-                  sym = Nodes::Symbol === sym ? sym.regexp : sym.left
-                end
-
-                @inverted[from][sym] << to
-              }
-            }
-
-            @inverted
-          end
-      end
-    end
-  end
-end
diff --git a/actionpack/test/journey/gtg/builder_test.rb b/actionpack/test/journey/gtg/builder_test.rb
index b92460884d..9dc786e261 100644
--- a/actionpack/test/journey/gtg/builder_test.rb
+++ b/actionpack/test/journey/gtg/builder_test.rb
@@ -40,10 +40,10 @@ module ActionDispatch
             /articles/:id(.:format)
           }
 
-          sim = NFA::Simulator.new table
+          sim = Simulator.new table
 
-          match = sim.match "/articles/new"
-          assert_equal 2, match.memos.length
+          memos = sim.memos "/articles/new"
+          assert_equal 2, memos.length
         end
 
         ##
@@ -54,10 +54,10 @@ module ActionDispatch
             /articles/new(.:format)
           }
 
-          sim = NFA::Simulator.new table
+          sim = Simulator.new table
 
-          match = sim.match "/articles/new"
-          assert_equal 2, match.memos.length
+          memos = sim.memos "/articles/new"
+          assert_equal 2, memos.length
         end
 
         private
diff --git a/actionpack/test/journey/nfa/simulator_test.rb b/actionpack/test/journey/nfa/simulator_test.rb
deleted file mode 100644
index 6b9f87b452..0000000000
--- a/actionpack/test/journey/nfa/simulator_test.rb
+++ /dev/null
@@ -1,100 +0,0 @@
-# frozen_string_literal: true
-
-require "abstract_unit"
-
-module ActionDispatch
-  module Journey
-    module NFA
-      class TestSimulator < ActiveSupport::TestCase
-        def test_simulate_simple
-          sim = simulator_for ["/foo"]
-          assert_match sim, "/foo"
-        end
-
-        def test_simulate_simple_no_match
-          sim = simulator_for ["/foo"]
-          assert_no_match sim, "foo"
-        end
-
-        def test_simulate_simple_no_match_too_long
-          sim = simulator_for ["/foo"]
-          assert_no_match sim, "/foo/bar"
-        end
-
-        def test_simulate_simple_no_match_wrong_string
-          sim = simulator_for ["/foo"]
-          assert_no_match sim, "/bar"
-        end
-
-        def test_simulate_regex
-          sim = simulator_for ["/:foo/bar"]
-          assert_match sim, "/bar/bar"
-          assert_match sim, "/foo/bar"
-        end
-
-        def test_simulate_or
-          sim = simulator_for ["/foo", "/bar"]
-          assert_match sim, "/bar"
-          assert_match sim, "/foo"
-          assert_no_match sim, "/baz"
-        end
-
-        def test_simulate_optional
-          sim = simulator_for ["/foo(/bar)"]
-          assert_match sim, "/foo"
-          assert_match sim, "/foo/bar"
-          assert_no_match sim, "/foo/"
-        end
-
-        def test_matchdata_has_memos
-          paths   = %w{ /foo /bar }
-          parser  = Journey::Parser.new
-          asts    = paths.map { |x|
-            ast = parser.parse x
-            ast.each { |n| n.memo = ast }
-            ast
-          }
-
-          expected = asts.first
-
-          builder = Builder.new Nodes::Or.new asts
-
-          sim = Simulator.new builder.transition_table
-
-          md = sim.match "/foo"
-          assert_equal [expected], md.memos
-        end
-
-        def test_matchdata_memos_on_merge
-          parser = Journey::Parser.new
-          routes = [
-            "/articles(.:format)",
-            "/articles/new(.:format)",
-            "/articles/:id/edit(.:format)",
-            "/articles/:id(.:format)",
-          ].map { |path|
-            ast = parser.parse path
-            ast.each { |n| n.memo = ast }
-            ast
-          }
-
-          asts = routes.dup
-
-          ast = Nodes::Or.new routes
-
-          nfa = Journey::NFA::Builder.new ast
-          sim = Simulator.new nfa.transition_table
-          md = sim.match "/articles"
-          assert_equal [asts.first], md.memos
-        end
-
-        def simulator_for(paths)
-          parser  = Journey::Parser.new
-          asts    = paths.map { |x| parser.parse x }
-          builder = Builder.new Nodes::Or.new asts
-          Simulator.new builder.transition_table
-        end
-      end
-    end
-  end
-end
diff --git a/actionpack/test/journey/nfa/transition_table_test.rb b/actionpack/test/journey/nfa/transition_table_test.rb
deleted file mode 100644
index c23611e980..0000000000
--- a/actionpack/test/journey/nfa/transition_table_test.rb
+++ /dev/null
@@ -1,74 +0,0 @@
-# frozen_string_literal: true
-
-require "abstract_unit"
-
-module ActionDispatch
-  module Journey
-    module NFA
-      class TestTransitionTable < ActiveSupport::TestCase
-        def setup
-          @parser = Journey::Parser.new
-        end
-
-        def test_eclosure
-          table = tt "/"
-          assert_equal [0], table.eclosure(0)
-
-          table = tt ":a|:b"
-          assert_equal 3, table.eclosure(0).length
-
-          table = tt "(:a|:b)"
-          assert_equal 5, table.eclosure(0).length
-          assert_equal 5, table.eclosure([0]).length
-        end
-
-        def test_following_states_one
-          table = tt "/"
-
-          assert_equal [1], table.following_states(0, "/")
-          assert_equal [1], table.following_states([0], "/")
-        end
-
-        def test_following_states_group
-          table  = tt "a|b"
-          states = table.eclosure 0
-
-          assert_equal 1, table.following_states(states, "a").length
-          assert_equal 1, table.following_states(states, "b").length
-        end
-
-        def test_following_states_multi
-          table  = tt "a|a"
-          states = table.eclosure 0
-
-          assert_equal 2, table.following_states(states, "a").length
-          assert_equal 0, table.following_states(states, "b").length
-        end
-
-        def test_following_states_regexp
-          table  = tt "a|:a"
-          states = table.eclosure 0
-
-          assert_equal 1, table.following_states(states, "a").length
-          assert_equal 1, table.following_states(states, /[^\.\/\?]+/).length
-          assert_equal 0, table.following_states(states, "b").length
-        end
-
-        def test_alphabet
-          table = tt "a|:a"
-          assert_equal [/[^\.\/\?]+/, "a"], table.alphabet
-
-          table = tt "a|a"
-          assert_equal ["a"], table.alphabet
-        end
-
-        private
-          def tt(string)
-            ast     = @parser.parse string
-            builder = Builder.new ast
-            builder.transition_table
-          end
-      end
-    end
-  end
-end