diff --git a/libs/ardour/ardour/transport_fsm.h b/libs/ardour/ardour/transport_fsm.h
index 004141a27a..77d9b9d864 100644
--- a/libs/ardour/ardour/transport_fsm.h
+++ b/libs/ardour/ardour/transport_fsm.h
@@ -127,27 +127,27 @@ struct TransportFSM
 
 	/* transition actions */
 
-	void schedule_butler_for_transport_work ();
-	void start_playback ();
-	void stop_playback ();
-	void start_saved_locate ();
-	void roll_after_locate ();
-	void start_locate (Event const &);
-	void interrupt_locate (Event const &);
+	void schedule_butler_for_transport_work () const;
+	void start_playback () const;
+	void stop_playback () const;
+	void start_saved_locate () const;
+	void roll_after_locate () const;
+	void start_locate (Event const &) const;
+	void interrupt_locate (Event const &) const;
 	void save_locate_and_start_declick (Event const &);
 	void start_declick (Event const &);
 
 	/* guards */
 
-	bool should_roll_after_locate ();
-	bool should_not_roll_after_locate ()  { return !should_roll_after_locate (); }
+	bool should_roll_after_locate () const;
+	bool should_not_roll_after_locate ()  const { return !should_roll_after_locate (); }
 
   public:
-	bool locating ()                     { return _motion_state == WaitingForLocate; }
-	bool rolling ()                      { return _motion_state == Rolling; }
-	bool stopped ()                      { return _motion_state == Stopped; }
-	bool waiting_for_butler()            { return _butler_state == WaitingForButler; }
-	bool declick_in_progress()           { return _motion_state == DeclickToLocate || _motion_state == DeclickToStop; }
+	bool locating () const           { return _motion_state == WaitingForLocate; }
+	bool rolling () const            { return _motion_state == Rolling; }
+	bool stopped () const            { return _motion_state == Stopped; }
+	bool waiting_for_butler() const  { return _butler_state == WaitingForButler; }
+	bool declick_in_progress() const { return _motion_state == DeclickToLocate || _motion_state == DeclickToStop; }
 
 	void enqueue (Event* ev) {
 		queued_events.push_back (*ev);
diff --git a/libs/ardour/transport_fsm.cc b/libs/ardour/transport_fsm.cc
index 5f394f9bd7..d01d09aaa1 100644
--- a/libs/ardour/transport_fsm.cc
+++ b/libs/ardour/transport_fsm.cc
@@ -298,7 +298,7 @@ TransportFSM::process_event (Event& ev)
 /* transition actions */
 
 void
-TransportFSM::start_playback ()
+TransportFSM::start_playback () const
 {
 	DEBUG_TRACE (DEBUG::TFSMEvents, "tfsm::start_playback\n");
 	api->start_transport();
@@ -313,7 +313,7 @@ TransportFSM::start_declick (Event const & s)
 }
 
 void
-TransportFSM::stop_playback ()
+TransportFSM::stop_playback () const
 {
 	DEBUG_TRACE (DEBUG::TFSMEvents, "tfsm::stop_playback\n");
 	api->stop_transport (_last_stop.abort, _last_stop.clear_state);
@@ -329,7 +329,7 @@ TransportFSM::save_locate_and_start_declick (Event const & l)
 }
 
 void
-TransportFSM::start_locate (Event const & l)
+TransportFSM::start_locate (Event const & l) const
 {
 	assert (l.type == Locate);
 	DEBUG_TRACE (DEBUG::TFSMEvents, "tfsm::start_locate\n");
@@ -337,14 +337,14 @@ TransportFSM::start_locate (Event const & l)
 }
 
 void
-TransportFSM::start_saved_locate ()
+TransportFSM::start_saved_locate () const
 {
 	DEBUG_TRACE (DEBUG::TFSMEvents, "tfsm::start_save\n");
 	api->locate (_last_locate.target, _last_locate.with_roll, _last_locate.with_flush, _last_locate.with_loop, _last_locate.force);
 }
 
 void
-TransportFSM::interrupt_locate (Event const & l)
+TransportFSM::interrupt_locate (Event const & l) const
 {
 	assert (l.type == Locate);
 	DEBUG_TRACE (DEBUG::TFSMEvents, "tfsm::interrupt\n");
@@ -355,13 +355,13 @@ TransportFSM::interrupt_locate (Event const & l)
 }
 
 void
-TransportFSM::schedule_butler_for_transport_work ()
+TransportFSM::schedule_butler_for_transport_work () const
 {
 	api->schedule_butler_for_transport_work ();
 }
 
 bool
-TransportFSM::should_roll_after_locate ()
+TransportFSM::should_roll_after_locate () const
 {
 	bool ret = api->should_roll_after_locate ();
 	DEBUG_TRACE (DEBUG::TFSMEvents, string_compose ("tfsm::should_roll_after_locate() ? %1\n", ret));
@@ -369,7 +369,7 @@ TransportFSM::should_roll_after_locate ()
 }
 
 void
-TransportFSM::roll_after_locate ()
+TransportFSM::roll_after_locate () const
 {
 	DEBUG_TRACE (DEBUG::TFSMEvents, "rolling after locate\n");
 	api->start_transport ();