From 74bfe4e6d2d0870adff9abbfa26273672f7c426a Mon Sep 17 00:00:00 2001
From: Jonathan G Rennison <j.g.rennison@gmail.com>
Date: Sat, 13 Nov 2021 22:28:14 +0000
Subject: [PATCH] Allow placing routing restrictions on tunnel/bridge
 entrance/exit signals

No reserve through support
---
 docs/landscape.html                   |   1 +
 docs/landscape_grid.html              |   2 +-
 src/map.cpp                           |   1 +
 src/pathfinder/yapf/yapf_costrail.hpp |  55 ++++++++--
 src/pbs.cpp                           |  85 +++++++++++++---
 src/pbs.h                             |   4 +-
 src/rail_cmd.cpp                      |   5 +-
 src/rail_gui.cpp                      |   3 +
 src/saveload/afterload.cpp            |   8 ++
 src/saveload/extended_ver_sl.cpp      |   1 +
 src/saveload/extended_ver_sl.h        |   1 +
 src/tracerestrict.cpp                 |  39 ++++++--
 src/tracerestrict.h                   |  14 ++-
 src/tracerestrict_gui.cpp             |  28 ++++--
 src/train_cmd.cpp                     | 138 +++++++++++++++++++++-----
 src/tunnelbridge_cmd.cpp              |  58 ++++++++++-
 src/tunnelbridge_map.h                |  20 ++++
 src/zoning_cmd.cpp                    |   3 +
 18 files changed, 393 insertions(+), 73 deletions(-)

diff --git a/docs/landscape.html b/docs/landscape.html
index c8886be7d8..328f07ab0c 100644
--- a/docs/landscape.html
+++ b/docs/landscape.html
@@ -1735,6 +1735,7 @@
       <ul>
        <li>m2 bit 15: for bridge entrances only: storage for visual red/green state of signals starting from 15 is allocated outside the map array</li>
        <li>m2 bits 14..4: for bridge entrances only: for signals 0..10 on bridge, signal is visually red if corresponding bit in 4..14 is set</li>
+       <li>m3 bit 6: the entrance and/or exit signals on this tile are restricted (tracerestrict patch)</li>
        <li>m3 bits 5..3: entrance signal aspect (only valid if signal is present and not red, and multi-aspect signalling is in effect)</li>
        <li>m3 bits 2..0: exit signal aspect (only valid if signal is present and not red, and multi-aspect signalling is in effect)</li>
        <li>m6 bit 7: set = exit signal shows green, clear = exit signal shows red</li>
diff --git a/docs/landscape_grid.html b/docs/landscape_grid.html
index de2d94fb0e..19b7309117 100644
--- a/docs/landscape_grid.html
+++ b/docs/landscape_grid.html
@@ -287,7 +287,7 @@ the array so you can quickly see what is used and what is not.
       <td class="caption">tunnel entrance</td>
       <td class="bits" rowspan=3><span class="free">OOO</span> <span class="used" title="Owner">XXXXX</span></td>
       <td class="bits"><span class="patch-pool" title="Tunnel index on pool (or overflow sentinel)">PPPP PPPP PPPP PPPP</span></td>
-      <td class="bits" rowspan=4><span class="rearrange" title="Owner of tram (road only; a rearrangement can free some of these bits)">XXXX</span> <span class="free">OOOO</span><br /><span class="free">OO</span> <span class="patch" title="Entrance/exit signal aspects (rail only)">PPPPPP</span></td>
+      <td class="bits" rowspan=4><span class="rearrange" title="Owner of tram (road only; a rearrangement can free some of these bits)">XXXX</span> <span class="free">OOOO</span><br /><span class="free">O</span><span class="patch" title="Routing restrictions present on entrance/exit signal(s)">P</span> <span class="patch" title="Entrance/exit signal aspects (rail only)">PPPPPP</span></td>
       <td class="bits"><span class="free">OO</span><span class="used" title="Road type">XX XXXX</span></td>
       <td class="bits"><span class="used" title="Bridge or tunnel bit">O</span><span class="patch" title="Signal simulation mode (rail only)">PP</span><span class="rearrange" title="PBS reservation (rail; a rearrangement can free some of these bits)">X</span> <span class="used" title="Transport type">XX</span> <span class="used" title="Direction of the tunnel/bridge">XX</span></td>
       <td class="bits"><span class="patch" title="PBS mode, exit signal state">PP</span><span class="free">OO OO</span><span class="patch" title="Semaphore/light mode, entrance signal state">PP</span></td>
diff --git a/src/map.cpp b/src/map.cpp
index 4778fd9c5a..aa59cc3c13 100644
--- a/src/map.cpp
+++ b/src/map.cpp
@@ -572,6 +572,7 @@ void DumpMapStats(char *b, const char *last)
 			if (IsTunnelBridgeWithSignalSimulation(t)) {
 				bucket |= TBB_SIGNALLED;
 				if (IsTunnelBridgeSignalSimulationBidirectional(t)) bucket |= TBB_SIGNALLED_BIDI;
+				if (IsTunnelBridgeRestrictedSignal(t)) restricted_signals++;
 			}
 			if (GetTunnelBridgeTransportType(t) == TRANSPORT_ROAD) {
 				if (HasTileRoadType(t, RTT_ROAD)) bucket |= TBB_ROAD;
diff --git a/src/pathfinder/yapf/yapf_costrail.hpp b/src/pathfinder/yapf/yapf_costrail.hpp
index a4a2096540..bd192255ef 100644
--- a/src/pathfinder/yapf/yapf_costrail.hpp
+++ b/src/pathfinder/yapf/yapf_costrail.hpp
@@ -176,6 +176,13 @@ private:
 				IsRestrictedSignal(tile);
 	}
 
+	// returns true if ExecuteTunnelBridgeTraceRestrict should be called
+	inline bool ShouldCheckTunnelBridgeTraceRestrict(Node& n, TileIndex tile)
+	{
+		return n.m_num_signals_passed < m_sig_look_ahead_costs.size() &&
+				IsTunnelBridgeRestrictedSignal(tile);
+	}
+
 	/**
 	 * This is called to retrieve the previous signal, as required
 	 * This is not run all the time as it is somewhat expensive and most restrictions will not test for the previous signal
@@ -312,6 +319,22 @@ private:
 		return false;
 	}
 
+	// returns true if dead end bit has been set
+	inline bool ExecuteTunnelBridgeTraceRestrict(Node& n, TileIndex tile, Trackdir trackdir, int& cost, TraceRestrictProgramResult &out)
+	{
+		const TraceRestrictProgram *prog = GetExistingTraceRestrictProgram(tile, TrackdirToTrack(trackdir));
+		TraceRestrictProgramActionsUsedFlags flags_to_check = TRPAUF_PF;
+		if (prog && prog->actions_used_flags & flags_to_check) {
+			prog->Execute(Yapf().GetVehicle(), TraceRestrictProgramInput(tile, trackdir, &TraceRestrictPreviousSignalCallback, &n), out);
+			if (out.flags & TRPRF_DENY) {
+				n.m_segment->m_end_segment_reason |= ESRB_DEAD_END;
+				return true;
+			}
+			cost += out.penalty;
+		}
+		return false;
+	}
+
 public:
 	int SignalCost(Node &n, TileIndex tile, Trackdir trackdir)
 	{
@@ -417,17 +440,27 @@ public:
 				}
 			}
 		}
-		if (IsTileType(tile, MP_TUNNELBRIDGE) && IsTunnelBridgeSignalSimulationExitOnly(tile) && TrackdirEntersTunnelBridge(tile, trackdir)) {
-			/* Entering a signalled bridge/tunnel from the wrong side, equivalent to encountering a one-way signal from the wrong side */
-			n.m_segment->m_end_segment_reason |= ESRB_DEAD_END;
-		}
-		if (IsTileType(tile, MP_TUNNELBRIDGE) && IsTunnelBridgeSignalSimulationExit(tile) && IsTunnelBridgeEffectivelyPBS(tile) && TrackdirExitsTunnelBridge(tile, trackdir)) {
-			/* Exiting a PBS signalled tunnel/bridge, record the last non-reserve through signal */
-			n.m_last_non_reserve_through_signal_tile = tile;
-			n.m_last_non_reserve_through_signal_td = trackdir;
-		}
-		if (n.flags_u.flags_s.m_reverse_pending && IsTileType(tile, MP_TUNNELBRIDGE) && IsTunnelBridgeSignalSimulationEntrance(tile)) {
-			n.m_segment->m_end_segment_reason |= ESRB_SAFE_TILE;
+		if (IsTunnelBridgeWithSignalSimulation(tile)) {
+			const bool entering = TrackdirEntersTunnelBridge(tile, trackdir);
+			const bool exiting = TrackdirExitsTunnelBridge(tile, trackdir);
+			if (IsTunnelBridgeSignalSimulationExitOnly(tile) && entering) {
+				/* Entering a signalled bridge/tunnel from the wrong side, equivalent to encountering a one-way signal from the wrong side */
+				n.m_segment->m_end_segment_reason |= ESRB_DEAD_END;
+			}
+			if (IsTunnelBridgeSignalSimulationExit(tile) && IsTunnelBridgeEffectivelyPBS(tile) && exiting) {
+				/* Exiting a PBS signalled tunnel/bridge, record the last non-reserve through signal */
+				n.m_last_non_reserve_through_signal_tile = tile;
+				n.m_last_non_reserve_through_signal_td = trackdir;
+			}
+			if (ShouldCheckTunnelBridgeTraceRestrict(n, tile)) {
+				TraceRestrictProgramResult out;
+				if (ExecuteTunnelBridgeTraceRestrict(n, tile, trackdir, cost, out)) {
+					return -1;
+				}
+			}
+			if (n.flags_u.flags_s.m_reverse_pending && entering && IsTunnelBridgeSignalSimulationEntrance(tile)) {
+				n.m_segment->m_end_segment_reason |= ESRB_SAFE_TILE;
+			}
 		}
 		return cost;
 	}
diff --git a/src/pbs.cpp b/src/pbs.cpp
index 6b52f10dae..35cd42e2ac 100644
--- a/src/pbs.cpp
+++ b/src/pbs.cpp
@@ -353,6 +353,39 @@ static int LookaheadTileHeightForChunnel(int length, int offset)
 	return 0;
 }
 
+static uint16 ApplyTunnelBridgeLookaheadSignalSpeedRestriction(TileIndex tile, Trackdir trackdir, const Train *v,
+		uint16 initial_speed_restriction, TrainReservationLookAhead *lookahead, int offset, int16 z)
+{
+	uint16 speed_restriction = initial_speed_restriction;
+
+	if (v != nullptr && IsTunnelBridgeRestrictedSignal(tile)) {
+		if (trackdir == INVALID_TRACKDIR) {
+			trackdir = GetTunnelBridgeExitTrackdir(tile);
+		}
+		const TraceRestrictProgram *prog = GetExistingTraceRestrictProgram(tile, TrackdirToTrack(trackdir));
+		if (prog && prog->actions_used_flags & TRPAUF_SPEED_RESTRICTION) {
+			TraceRestrictProgramResult out;
+			TraceRestrictProgramInput input(tile, trackdir, nullptr, nullptr);
+			prog->Execute(v, input, out);
+			if (out.flags & TRPRF_SPEED_RESTRICTION_SET) {
+				int duration;
+				if (TrackdirEntersTunnelBridge(tile, trackdir)) {
+					duration = 4 + (IsDiagonalTrackdir(trackdir) ? 16 : 8);
+				} else {
+					duration = 4;
+				}
+				lookahead->AddSpeedRestriction(out.speed_restriction, offset, duration, z);
+				if (out.speed_restriction != 0 && (speed_restriction == 0 || out.speed_restriction < speed_restriction)) {
+					/* lower of the speed restrictions before or after the signal */
+					speed_restriction = out.speed_restriction;
+				}
+			}
+		}
+	}
+
+	return speed_restriction;
+}
+
 /** Follow a reservation starting from a specific tile to the end. */
 static PBSTileInfo FollowReservation(Owner o, RailTypes rts, TileIndex tile, Trackdir trackdir, FollowReservationFlags flags, const Train *v, TrainReservationLookAhead *lookahead)
 {
@@ -525,8 +558,10 @@ static PBSTileInfo FollowReservation(Owner o, RailTypes rts, TileIndex tile, Tra
 					const int spacing = GetTunnelBridgeSignalSimulationSpacing(tile);
 					const int signals = length / spacing;
 
+					uint16 speed_restriction = ApplyTunnelBridgeLookaheadSignalSpeedRestriction(tile, trackdir, v, lookahead->speed_restriction, lookahead, 0, z);
+
 					uint16 signal_speed = GetRailTypeInfo(rt)->max_speed;
-					if (signal_speed == 0 || (lookahead->speed_restriction != 0 && lookahead->speed_restriction < signal_speed)) signal_speed = lookahead->speed_restriction;
+					if (signal_speed == 0 || (speed_restriction != 0 && speed_restriction < signal_speed)) signal_speed = speed_restriction;
 					if (signal_speed == 0 || (bridge_speed != 0 && bridge_speed < signal_speed)) signal_speed = bridge_speed;
 
 					/* Entrance signal */
@@ -548,7 +583,16 @@ static PBSTileInfo FollowReservation(Owner o, RailTypes rts, TileIndex tile, Tra
 					}
 
 					/* Exit signal */
-					const int end_offset = start_offset + (TILE_SIZE * length) /* + ((DiagDirToDiagTrackBits(GetTunnelBridgeDirection(end)) & GetTunnelBridgeTrackBits(end)) ? 16 : 8)*/;
+					const int end_offset = start_offset + (TILE_SIZE * length);
+
+					uint16 exit_speed_restriction = ApplyTunnelBridgeLookaheadSignalSpeedRestriction(end, INVALID_TRACKDIR, v, lookahead->speed_restriction, lookahead, end_offset, z);
+					if (exit_speed_restriction != speed_restriction) {
+						speed_restriction = exit_speed_restriction;
+						signal_speed = GetRailTypeInfo(rt)->max_speed;
+						if (signal_speed == 0 || (speed_restriction != 0 && speed_restriction < signal_speed)) signal_speed = speed_restriction;
+						if (signal_speed == 0 || (bridge_speed != 0 && bridge_speed < signal_speed)) signal_speed = bridge_speed;
+					}
+
 					lookahead->AddSignal(signal_speed, end_offset, z);
 
 					lookahead->SetNextExtendPositionIfUnset();
@@ -580,7 +624,7 @@ static PBSTileInfo FollowReservation(Owner o, RailTypes rts, TileIndex tile, Tra
 							lookahead->AddReverse(z);
 						}
 						if (out.flags & TRPRF_SPEED_RESTRICTION_SET) {
-							lookahead->AddSpeedRestriction(out.speed_restriction, z);
+							lookahead->AddSpeedRestriction(out.speed_restriction, 0, 0, z);
 							if (out.speed_restriction != 0 && (speed_restriction == 0 || out.speed_restriction < speed_restriction)) {
 								/* lower of the speed restrictions before or after the signal */
 								speed_restriction = out.speed_restriction;
@@ -869,12 +913,14 @@ void TryCreateLookAheadForTrainInTunnelBridge(Train *t)
 		if (IsTunnel(t->tile) && Tunnel::GetByTile(t->tile)->is_chunnel) SetBit(t->lookahead->flags, TRLF_CHUNNEL);
 
 		if (IsTunnelBridgeSignalSimulationEntrance(t->tile)) {
-			uint16 bridge_speed = IsBridge(t->tile) ? GetBridgeSpec(GetBridgeType(t->tile))->speed : 0;
-			const int length = GetTunnelBridgeLength(t->tile, GetOtherTunnelBridgeEnd(t->tile));
+			const uint16 bridge_speed = IsBridge(t->tile) ? GetBridgeSpec(GetBridgeType(t->tile))->speed : 0;
+			const TileIndex end = GetOtherTunnelBridgeEnd(t->tile);
+			const int length = GetTunnelBridgeLength(t->tile, end);
 			const int spacing = GetTunnelBridgeSignalSimulationSpacing(t->tile);
 			const int signals = length / spacing;
 
-			uint16 signal_speed = GetRailTypeInfo(GetRailTypeByTrack(t->tile, TrackdirToTrack(t->lookahead->reservation_end_trackdir)))->max_speed;
+			const RailType rt = GetRailTypeByTrack(t->tile, TrackdirToTrack(t->lookahead->reservation_end_trackdir));
+			uint16 signal_speed = GetRailTypeInfo(rt)->max_speed;
 			if (signal_speed == 0 || (t->speed_restriction != 0 && t->speed_restriction < signal_speed)) signal_speed = t->speed_restriction;
 			if (signal_speed == 0 || (bridge_speed != 0 && bridge_speed < signal_speed)) signal_speed = bridge_speed;
 
@@ -889,6 +935,14 @@ void TryCreateLookAheadForTrainInTunnelBridge(Train *t)
 
 			/* Exit signal */
 			const int end_offset = TILE_SIZE * length;
+
+			uint16 exit_speed_restriction = ApplyTunnelBridgeLookaheadSignalSpeedRestriction(end, INVALID_TRACKDIR, t, t->speed_restriction, t->lookahead.get(), end_offset, z);
+			if (exit_speed_restriction != t->speed_restriction) {
+				signal_speed = GetRailTypeInfo(rt)->max_speed;
+				if (signal_speed == 0 || (exit_speed_restriction != 0 && exit_speed_restriction < signal_speed)) signal_speed = exit_speed_restriction;
+				if (signal_speed == 0 || (bridge_speed != 0 && bridge_speed < signal_speed)) signal_speed = bridge_speed;
+			}
+
 			t->lookahead->AddSignal(signal_speed, end_offset, z);
 
 			t->lookahead->SetNextExtendPositionIfUnset();
@@ -1157,10 +1211,8 @@ bool IsSafeWaitingPosition(const Train *v, TileIndex tile, Trackdir trackdir, bo
 		if (HasSignalOnTrackdir(tile, trackdir) && !IsPbsSignal(GetSignalType(tile, TrackdirToTrack(trackdir)))) return true;
 	}
 
-	if (IsRailTunnelBridgeTile(tile) && IsTrackAcrossTunnelBridge(tile, TrackdirToTrack(trackdir))) {
-		if (IsTunnelBridgeSignalSimulationEntrance(tile)) {
-			return true;
-		}
+	if (IsTunnelBridgeSignalSimulationEntranceTile(tile) && IsTrackAcrossTunnelBridge(tile, TrackdirToTrack(trackdir))) {
+		return true;
 	}
 
 	/* Check next tile. For performance reasons, we check for 90 degree turns ourself. */
@@ -1229,8 +1281,8 @@ bool IsWaitingPositionFree(const Train *v, TileIndex tile, Trackdir trackdir, bo
 	/* Not reserved and depot or not a pbs signal -> free. */
 	if (IsRailDepotTile(tile)) return true;
 
-	auto pbs_res_end_wait_test = [v, restricted_signal_info](TileIndex t, Trackdir td) -> bool {
-		if (IsRestrictedSignal(t)) {
+	auto pbs_res_end_wait_test = [v, restricted_signal_info](TileIndex t, Trackdir td, bool tunnel_bridge) -> bool {
+		if (tunnel_bridge ? IsTunnelBridgeRestrictedSignal(t) : IsRestrictedSignal(t)) {
 			const TraceRestrictProgram *prog = GetExistingTraceRestrictProgram(t, TrackdirToTrack(td));
 			if (restricted_signal_info && prog) {
 				restricted_signal_info->tile = t;
@@ -1250,11 +1302,12 @@ bool IsWaitingPositionFree(const Train *v, TileIndex tile, Trackdir trackdir, bo
 	};
 
 	if (IsTileType(tile, MP_RAILWAY) && HasSignalOnTrackdir(tile, trackdir) && !IsPbsSignal(GetSignalType(tile, track))) {
-		return pbs_res_end_wait_test(tile, trackdir);
+		return pbs_res_end_wait_test(tile, trackdir, false);
 	}
 
 	if (IsTunnelBridgeSignalSimulationEntranceTile(tile) && IsTrackAcrossTunnelBridge(tile, TrackdirToTrack(trackdir))) {
-		if (IsTunnelBridgeSignalSimulationBidirectional(tile)) {
+		bool free = pbs_res_end_wait_test(tile, trackdir, true);
+		if (free && IsTunnelBridgeSignalSimulationBidirectional(tile)) {
 			TileIndex other_end = GetOtherTunnelBridgeEnd(tile);
 			if (HasAcrossTunnelBridgeReservation(other_end) && GetTunnelBridgeExitSignalState(other_end) == SIGNAL_STATE_RED) return false;
 			Direction dir = DiagDirToDir(GetTunnelBridgeDirection(other_end));
@@ -1267,7 +1320,7 @@ bool IsWaitingPositionFree(const Train *v, TileIndex tile, Trackdir trackdir, bo
 				return nullptr;
 			})) return false;
 		}
-		return true;
+		return free;
 	}
 
 	/* Check the next tile, if it's a PBS signal, it has to be free as well. */
@@ -1285,7 +1338,7 @@ bool IsWaitingPositionFree(const Train *v, TileIndex tile, Trackdir trackdir, bo
 		Trackdir td = FindFirstTrackdir(ft.m_new_td_bits);
 		/* PBS signal on next trackdir? */
 		if (HasPbsSignalOnTrackdir(ft.m_new_tile, td)) {
-			return pbs_res_end_wait_test(ft.m_new_tile, td);
+			return pbs_res_end_wait_test(ft.m_new_tile, td, false);
 		}
 	}
 
diff --git a/src/pbs.h b/src/pbs.h
index 50d69027e5..398ecbd37d 100644
--- a/src/pbs.h
+++ b/src/pbs.h
@@ -114,10 +114,10 @@ struct TrainReservationLookAhead {
 		this->items.push_back({ end + offset, end + offset + duration, z_pos, speed, TRLIT_TRACK_SPEED });
 	}
 
-	void AddSpeedRestriction(uint16 speed, int16 z_pos)
+	void AddSpeedRestriction(uint16 speed, int offset, int duration, int16 z_pos)
 	{
 		int end = this->RealEndPosition();
-		this->items.push_back({ end, end, z_pos, speed, TRLIT_SPEED_RESTRICTION });
+		this->items.push_back({ end + offset, end + offset + duration, z_pos, speed, TRLIT_SPEED_RESTRICTION });
 		this->speed_restriction = speed;
 	}
 
diff --git a/src/rail_cmd.cpp b/src/rail_cmd.cpp
index 495c601196..cc3d50e389 100644
--- a/src/rail_cmd.cpp
+++ b/src/rail_cmd.cpp
@@ -2110,6 +2110,7 @@ CommandCost CmdRemoveSingleSignal(TileIndex tile, DoCommandFlag flags, uint32 p1
 			}
 		}
 		if (flags & DC_EXEC) {
+			Track end_track = FindFirstTrack(GetAcrossTunnelBridgeTrackBits(end));
 			Company *c = Company::Get(GetTileOwner(tile));
 			c->infrastructure.signal -= GetTunnelBridgeSignalSimulationSignalCount(tile, end);
 			ClearBridgeTunnelSignalSimulation(end, tile);
@@ -2118,7 +2119,9 @@ CommandCost CmdRemoveSingleSignal(TileIndex tile, DoCommandFlag flags, uint32 p1
 			AddSideToSignalBuffer(tile, INVALID_DIAGDIR, GetTileOwner(tile));
 			AddSideToSignalBuffer(end, INVALID_DIAGDIR, GetTileOwner(tile));
 			YapfNotifyTrackLayoutChange(tile, track);
-			YapfNotifyTrackLayoutChange(end, track);
+			YapfNotifyTrackLayoutChange(end, end_track);
+			TraceRestrictNotifySignalRemoval(tile, track);
+			TraceRestrictNotifySignalRemoval(end, end_track);
 			DirtyCompanyInfrastructureWindows(GetTileOwner(tile));
 			for (Train *v : re_reserve_trains) {
 				ReReserveTrainPath(v);
diff --git a/src/rail_gui.cpp b/src/rail_gui.cpp
index 179612506e..6249ea7b6c 100644
--- a/src/rail_gui.cpp
+++ b/src/rail_gui.cpp
@@ -248,6 +248,9 @@ static void GenericPlaceSignals(TileIndex tile)
 		if (IsPlainRailTile(tile) && HasTrack(tile, track) && HasSignalOnTrack(tile, track)) {
 			ShowTraceRestrictProgramWindow(tile, track);
 		}
+		if (IsTunnelBridgeWithSignalSimulation(tile) && HasTrack(GetAcrossTunnelBridgeTrackBits(tile), track)) {
+			ShowTraceRestrictProgramWindow(tile, track);
+		}
 		return;
 	}
 
diff --git a/src/saveload/afterload.cpp b/src/saveload/afterload.cpp
index 4affa30050..85e4eeaec3 100644
--- a/src/saveload/afterload.cpp
+++ b/src/saveload/afterload.cpp
@@ -3971,6 +3971,14 @@ bool AfterLoadGame()
 		}
 	}
 
+	if (SlXvIsFeatureMissing(XSLFI_TRACE_RESTRICT_TUNBRIDGE)) {
+		for (TileIndex t = 0; t < map_size; t++) {
+			if (IsTileType(t, MP_TUNNELBRIDGE) && GetTunnelBridgeTransportType(t) == TRANSPORT_RAIL && IsTunnelBridgeWithSignalSimulation(t)) {
+				SetTunnelBridgeRestrictedSignal(t, false);
+			}
+		}
+	}
+
 	InitializeRoadGUI();
 
 	/* This needs to be done after conversion. */
diff --git a/src/saveload/extended_ver_sl.cpp b/src/saveload/extended_ver_sl.cpp
index f23bc4223a..1399b169d7 100644
--- a/src/saveload/extended_ver_sl.cpp
+++ b/src/saveload/extended_ver_sl.cpp
@@ -80,6 +80,7 @@ const SlxiSubChunkInfo _sl_xv_sub_chunk_infos[] = {
 	{ XSLFI_TRACE_RESTRICT_BRKCND,  XSCF_NULL,                2,   2, "tracerestrict_braking_cond",nullptr, nullptr, nullptr        },
 	{ XSLFI_TRACE_RESTRICT_CTGRYCND,XSCF_NULL,                1,   1, "tracerestrict_ctgry_cond",  nullptr, nullptr, nullptr        },
 	{ XSLFI_TRACE_RESTRICT_PENCTRL, XSCF_NULL,                1,   1, "tracerestrict_pfpenctrl",   nullptr, nullptr, nullptr        },
+	{ XSLFI_TRACE_RESTRICT_TUNBRIDGE,XSCF_NULL,               1,   1, "tracerestrict_sigtunbridge",nullptr, nullptr, nullptr        },
 	{ XSLFI_PROG_SIGS,              XSCF_NULL,                2,   2, "programmable_signals",      nullptr, nullptr, "SPRG"      },
 	{ XSLFI_ADJACENT_CROSSINGS,     XSCF_NULL,                1,   1, "adjacent_crossings",        nullptr, nullptr, nullptr        },
 	{ XSLFI_SAFER_CROSSINGS,        XSCF_NULL,                1,   1, "safer_crossings",           nullptr, nullptr, nullptr        },
diff --git a/src/saveload/extended_ver_sl.h b/src/saveload/extended_ver_sl.h
index 52f74b1908..387fb34d05 100644
--- a/src/saveload/extended_ver_sl.h
+++ b/src/saveload/extended_ver_sl.h
@@ -34,6 +34,7 @@ enum SlXvFeatureIndex {
 	XSLFI_TRACE_RESTRICT_BRKCND,                  ///< Trace restrict: realistic braking related conditionals
 	XSLFI_TRACE_RESTRICT_CTGRYCND,                ///< Trace restrict: category conditionals
 	XSLFI_TRACE_RESTRICT_PENCTRL,                 ///< Trace restrict: PF penalty control
+	XSLFI_TRACE_RESTRICT_TUNBRIDGE,               ///< Trace restrict: restricted signalled tunnel/bridge support
 	XSLFI_PROG_SIGS,                              ///< programmable pre-signals patch
 	XSLFI_ADJACENT_CROSSINGS,                     ///< Adjacent level crossings closure patch
 	XSLFI_SAFER_CROSSINGS,                        ///< Safer level crossings
diff --git a/src/tracerestrict.cpp b/src/tracerestrict.cpp
index 1f113dbaa7..0cb0c85571 100644
--- a/src/tracerestrict.cpp
+++ b/src/tracerestrict.cpp
@@ -1124,7 +1124,18 @@ void TraceRestrictSetIsSignalRestrictedBit(TileIndex t)
 	TraceRestrictMapping::iterator upper_bound = _tracerestrictprogram_mapping.lower_bound(MakeTraceRestrictRefId(t + 1, static_cast<Track>(0)));
 
 	// If iterators are the same, there are no mappings for this tile
-	SetRestrictedSignal(t, lower_bound != upper_bound);
+	switch (GetTileType(t)) {
+		case MP_RAILWAY:
+			SetRestrictedSignal(t, lower_bound != upper_bound);
+			break;
+
+		case MP_TUNNELBRIDGE:
+			SetTunnelBridgeRestrictedSignal(t, lower_bound != upper_bound);
+			break;
+
+		default:
+			NOT_REACHED();
+	}
 }
 
 /**
@@ -1251,11 +1262,27 @@ void TraceRestrictDoCommandP(TileIndex tile, Track track, TraceRestrictDoCommand
 static CommandCost TraceRestrictCheckTileIsUsable(TileIndex tile, Track track)
 {
 	// Check that there actually is a signal here
-	if (!IsPlainRailTile(tile) || !HasTrack(tile, track)) {
-		return_cmd_error(STR_ERROR_THERE_IS_NO_RAILROAD_TRACK);
-	}
-	if (!HasSignalOnTrack(tile, track)) {
-		return_cmd_error(STR_ERROR_THERE_ARE_NO_SIGNALS);
+	switch (GetTileType(tile)) {
+		case MP_RAILWAY:
+			if (!IsPlainRailTile(tile) || !HasTrack(tile, track)) {
+				return_cmd_error(STR_ERROR_THERE_IS_NO_RAILROAD_TRACK);
+			}
+			if (!HasSignalOnTrack(tile, track)) {
+				return_cmd_error(STR_ERROR_THERE_ARE_NO_SIGNALS);
+			}
+			break;
+
+		case MP_TUNNELBRIDGE:
+			if (!IsRailTunnelBridgeTile(tile) || !HasBit(GetTunnelBridgeTrackBits(tile), track)) {
+				return_cmd_error(STR_ERROR_THERE_IS_NO_RAILROAD_TRACK);
+			}
+			if (!IsTunnelBridgeWithSignalSimulation(tile) || !IsTrackAcrossTunnelBridge(tile, track)) {
+				return_cmd_error(STR_ERROR_THERE_ARE_NO_SIGNALS);
+			}
+			break;
+
+		default:
+			return_cmd_error(STR_ERROR_THERE_IS_NO_RAILROAD_TRACK);
 	}
 
 	// Check tile ownership, do this afterwards to avoid tripping up on house/industry tiles
diff --git a/src/tracerestrict.h b/src/tracerestrict.h
index 5df1c2abda..9f0f0b13c7 100644
--- a/src/tracerestrict.h
+++ b/src/tracerestrict.h
@@ -875,12 +875,24 @@ TraceRestrictProgram *GetTraceRestrictProgram(TraceRestrictRefId ref, bool creat
 
 void TraceRestrictNotifySignalRemoval(TileIndex tile, Track track);
 
+static inline bool IsRestrictedSignalTile(TileIndex t)
+{
+	switch (GetTileType(t)) {
+		case MP_RAILWAY:
+			return IsRestrictedSignal(t);
+		case MP_TUNNELBRIDGE:
+			return IsTunnelBridgeRestrictedSignal(t);
+		default:
+			return false;
+	}
+}
+
 /**
  * Gets the existing signal program for the tile identified by @p t and @p track, or nullptr
  */
 static inline const TraceRestrictProgram *GetExistingTraceRestrictProgram(TileIndex t, Track track)
 {
-	if (IsRestrictedSignal(t)) {
+	if (IsRestrictedSignalTile(t)) {
 		return GetTraceRestrictProgram(MakeTraceRestrictRefId(t, track), false);
 	} else {
 		return nullptr;
diff --git a/src/tracerestrict_gui.cpp b/src/tracerestrict_gui.cpp
index aba9c5b8f2..cce824d131 100644
--- a/src/tracerestrict_gui.cpp
+++ b/src/tracerestrict_gui.cpp
@@ -2093,7 +2093,7 @@ public:
 	 */
 	void OnPlaceObjectSignal(Point pt, TileIndex source_tile, int widget, int error_message)
 	{
-		if (!IsPlainRailTile(source_tile)) {
+		if (!IsPlainRailTile(source_tile) && !IsRailTunnelBridgeTile(source_tile)) {
 			ShowErrorMessage(error_message, STR_ERROR_THERE_IS_NO_RAILROAD_TRACK, WL_INFO);
 			return;
 		}
@@ -2112,14 +2112,26 @@ public:
 			return;
 		}
 
-		if (!HasTrack(source_tile, source_track)) {
-			ShowErrorMessage(error_message, STR_ERROR_THERE_IS_NO_RAILROAD_TRACK, WL_INFO);
-			return;
-		}
+		if (IsTileType(source_tile, MP_RAILWAY)) {
+			if (!HasTrack(source_tile, source_track)) {
+				ShowErrorMessage(error_message, STR_ERROR_THERE_IS_NO_RAILROAD_TRACK, WL_INFO);
+				return;
+			}
 
-		if (!HasSignalOnTrack(source_tile, source_track)) {
-			ShowErrorMessage(error_message, STR_ERROR_THERE_ARE_NO_SIGNALS, WL_INFO);
-			return;
+			if (!HasSignalOnTrack(source_tile, source_track)) {
+				ShowErrorMessage(error_message, STR_ERROR_THERE_ARE_NO_SIGNALS, WL_INFO);
+				return;
+			}
+		} else {
+			if (!HasTrack(GetTunnelBridgeTrackBits(source_tile), source_track)) {
+				ShowErrorMessage(error_message, STR_ERROR_THERE_IS_NO_RAILROAD_TRACK, WL_INFO);
+				return;
+			}
+
+			if (!IsTunnelBridgeWithSignalSimulation(source_tile) || !HasTrack(GetAcrossTunnelBridgeTrackBits(source_tile), source_track)) {
+				ShowErrorMessage(error_message, STR_ERROR_THERE_ARE_NO_SIGNALS, WL_INFO);
+				return;
+			}
 		}
 
 		switch (widget) {
diff --git a/src/train_cmd.cpp b/src/train_cmd.cpp
index f4dcfb4f22..0b6040a372 100644
--- a/src/train_cmd.cpp
+++ b/src/train_cmd.cpp
@@ -4001,11 +4001,12 @@ static bool HasLongReservePbsSignalOnTrackdir(Train* v, TileIndex tile, Trackdir
 	return false;
 }
 
-static TileIndex CheckLongReservePbsTunnelBridgeOnTrackdir(Train* v, TileIndex tile, Trackdir trackdir)
+static TileIndex CheckLongReservePbsTunnelBridgeOnTrackdir(Train* v, TileIndex tile, Trackdir trackdir, bool restricted_only = false)
 {
 	if (_settings_game.vehicle.train_braking_model == TBM_REALISTIC && IsTunnelBridgeSignalSimulationEntranceTile(tile) && TrackdirEntersTunnelBridge(tile, trackdir)) {
 
 		TileIndex end = GetOtherTunnelBridgeEnd(tile);
+		if (restricted_only && !IsTunnelBridgeRestrictedSignal(end)) return INVALID_TILE;
 		int raw_free_tiles;
 		if (v->lookahead != nullptr && v->lookahead->reservation_end_tile == tile && v->lookahead->reservation_end_trackdir == trackdir) { // TODO fix loop case
 			if (HasBit(v->lookahead->flags, TRLF_TB_EXIT_FREE)) {
@@ -4033,7 +4034,7 @@ static void TryLongReserveChooseTrainTrack(Train *v, TileIndex tile, Trackdir td
 	const bool long_enough = IsReservationLookAheadLongEnough(v, lookahead_state);
 
 	// We reserved up to a unoccupied signalled tunnel/bridge, reserve past it as well. recursion
-	TileIndex exit_tile = long_enough ? INVALID_TILE : CheckLongReservePbsTunnelBridgeOnTrackdir(v, tile, td);
+	TileIndex exit_tile = CheckLongReservePbsTunnelBridgeOnTrackdir(v, tile, td, long_enough);
 	if (exit_tile != INVALID_TILE) {
 		CFollowTrackRail ft(v);
 		Trackdir exit_td = GetTunnelBridgeExitTrackdir(exit_tile);
@@ -4042,6 +4043,23 @@ static void TryLongReserveChooseTrainTrack(Train *v, TileIndex tile, Trackdir td
 			if ((ft.m_new_td_bits & TrackBitsToTrackdirBits(reserved_bits)) == TRACKDIR_BIT_NONE) {
 				/* next tile is not reserved */
 
+				bool long_reserve = !long_enough;
+				if (IsTunnelBridgeRestrictedSignal(exit_tile)) {
+					const TraceRestrictProgram *prog = GetExistingTraceRestrictProgram(exit_tile, TrackdirToTrack(exit_td));
+					if (prog && prog->actions_used_flags & (TRPAUF_WAIT_AT_PBS | TRPAUF_SLOT_ACQUIRE | TRPAUF_SLOT_ACQUIRE_ON_RES | TRPAUF_LONG_RESERVE)) {
+						TraceRestrictProgramResult out;
+						if (long_reserve) out.flags |= TRPRF_LONG_RESERVE;
+						TraceRestrictProgramInput input(exit_tile, exit_td, nullptr, nullptr);
+						input.permitted_slot_operations = TRPISP_ACQUIRE | TRPISP_ACQUIRE_ON_RES;
+						prog->Execute(v, input, out);
+						if (out.flags & TRPRF_WAIT_AT_PBS) {
+							return;
+						}
+						long_reserve = (out.flags & TRPRF_LONG_RESERVE);
+					}
+				}
+				if (!long_reserve) return;
+
 				SignalState exit_state = GetTunnelBridgeExitSignalState(exit_tile);
 
 				/* reserve exit to make contiguous reservation */
@@ -4051,10 +4069,6 @@ static void TryLongReserveChooseTrainTrack(Train *v, TileIndex tile, Trackdir td
 					SetTunnelReservation(exit_tile, true);
 				}
 				SetTunnelBridgeExitSignalState(exit_tile, SIGNAL_STATE_GREEN);
-				if (_extra_aspects > 0) {
-					SetTunnelBridgeExitSignalAspect(exit_tile, 0);
-					UpdateAspectDeferred(exit_tile, GetTunnelBridgeExitTrackdir(exit_tile));
-				}
 
 				ChooseTrainTrack(v, ft.m_new_tile, ft.m_exitdir, TrackdirBitsToTrackBits(ft.m_new_td_bits), CTTF_NO_LOOKAHEAD_VALIDATE | (force_res ? CTTF_FORCE_RES : CTTF_NONE), nullptr, lookahead_state);
 
@@ -4067,6 +4081,10 @@ static void TryLongReserveChooseTrainTrack(Train *v, TileIndex tile, Trackdir td
 					}
 					SetTunnelBridgeExitSignalState(exit_tile, exit_state);
 				} else {
+					if (_extra_aspects > 0) {
+						SetTunnelBridgeExitSignalAspect(exit_tile, 0);
+						UpdateAspectDeferred(exit_tile, GetTunnelBridgeExitTrackdir(exit_tile));
+					}
 					MarkTileDirtyByTile(exit_tile, VMDF_NOT_MAP_MODE);
 				}
 			}
@@ -4995,6 +5013,23 @@ static bool CheckTrainStayInWormHolePathReserve(Train *t, TileIndex tile)
 		}
 	}
 
+	auto try_exit_reservation = [&]() -> bool {
+		if (IsTunnelBridgeRestrictedSignal(tile)) {
+			const TraceRestrictProgram *prog = GetExistingTraceRestrictProgram(tile, TrackdirToTrack(td));
+			if (prog && prog->actions_used_flags & (TRPAUF_WAIT_AT_PBS | TRPAUF_SLOT_ACQUIRE | TRPAUF_SLOT_ACQUIRE_ON_RES)) {
+				TraceRestrictProgramResult out;
+				TraceRestrictProgramInput input(tile, td, nullptr, nullptr);
+				input.permitted_slot_operations = TRPISP_ACQUIRE | TRPISP_ACQUIRE_ON_RES;
+				prog->Execute(t, input, out);
+				if (out.flags & TRPRF_WAIT_AT_PBS) {
+					return false;
+				}
+			}
+		}
+
+		return TryPathReserve(t);
+	};
+
 	if (_settings_game.vehicle.train_braking_model == TBM_REALISTIC) {
 		if (unlikely(t->lookahead == nullptr)) {
 			FillTrainReservationLookAhead(t);
@@ -5004,10 +5039,6 @@ static bool CheckTrainStayInWormHolePathReserve(Train *t, TileIndex tile)
 			if (t->lookahead->reservation_end_tile == t->tile && t->lookahead->reservation_end_position - t->lookahead->current_position <= (int)TILE_SIZE && !HasBit(t->lookahead->flags, TRLF_TB_EXIT_FREE)) return false;
 			SignalState exit_state = GetTunnelBridgeExitSignalState(tile);
 			SetTunnelBridgeExitSignalState(tile, SIGNAL_STATE_GREEN);
-			if (_extra_aspects > 0) {
-				SetTunnelBridgeExitSignalAspect(tile, 0);
-				UpdateAspectDeferred(tile, GetTunnelBridgeExitTrackdir(tile));
-			}
 
 			/* Get tile margin before changing vehicle direction */
 			const int tile_margin = GetTileMarginInFrontOfTrain(t);
@@ -5018,7 +5049,7 @@ static bool CheckTrainStayInWormHolePathReserve(Train *t, TileIndex tile)
 			t->tile = tile;
 			t->track = TRACK_BIT_WORMHOLE;
 			t->direction = TrackdirToDirection(td);
-			bool ok = TryPathReserve(t);
+			bool ok = try_exit_reservation();
 			if (!ok && (t->lookahead->reservation_end_position >= t->lookahead->current_position && t->lookahead->reservation_end_position > t->lookahead->current_position + tile_margin)) {
 				/* Reservation was made previously and was valid then.
 				 * To avoid unexpected braking due to stopping short of the lookahead end,
@@ -5026,6 +5057,10 @@ static bool CheckTrainStayInWormHolePathReserve(Train *t, TileIndex tile)
 				ok = true;
 			}
 			if (ok) {
+				if (_extra_aspects > 0) {
+					SetTunnelBridgeExitSignalAspect(tile, 0);
+					UpdateAspectDeferred(tile, GetTunnelBridgeExitTrackdir(tile));
+				}
 				mark_dirty = true;
 				if (t->lookahead->reservation_end_tile == veh_orig_tile && t->lookahead->reservation_end_position - t->lookahead->current_position <= (int)TILE_SIZE) {
 					/* Less than a tile of lookahead, advance tile */
@@ -5057,7 +5092,7 @@ static bool CheckTrainStayInWormHolePathReserve(Train *t, TileIndex tile)
 	t->tile = tile;
 	t->track = TRACK_BIT_WORMHOLE;
 	t->direction = TrackdirToDirection(td);
-	bool ok = TryPathReserve(t);
+	bool ok = try_exit_reservation();
 	t->tile = veh_orig_tile;
 	t->track = veh_orig_track;
 	t->direction = veh_orig_direction;
@@ -5170,6 +5205,21 @@ void DecrementPendingSpeedRestrictions(Train *v)
 	}
 }
 
+void HandleTraceRestrictSpeedRestrictionAction(const TraceRestrictProgramResult &out, Train *v, Trackdir signal_td)
+{
+	if (out.flags & TRPRF_SPEED_RESTRICTION_SET) {
+		SetBit(v->flags, VRF_PENDING_SPEED_RESTRICTION);
+		auto range = pending_speed_restriction_change_map.equal_range(v->index);
+		for (auto it = range.first; it != range.second; ++it) {
+			if ((uint16) (out.speed_restriction + 0xFFFF) < (uint16) (it->second.new_speed + 0xFFFF)) it->second.new_speed = out.speed_restriction;
+		}
+		uint16 flags = 0;
+		if (IsDiagonalTrack(TrackdirToTrack(signal_td))) SetBit(flags, PSRCF_DIAGONAL);
+		pending_speed_restriction_change_map.insert({ v->index, { (uint16) (v->gcache.cached_total_length + (HasBit(flags, PSRCF_DIAGONAL) ? 8 : 4)), out.speed_restriction, v->speed_restriction, flags } });
+		if ((uint16) (out.speed_restriction + 0xFFFF) < (uint16) (v->speed_restriction + 0xFFFF)) v->speed_restriction = out.speed_restriction;
+	}
+}
+
 /**
  * Move a vehicle chain one movement stop forwards.
  * @param v First vehicle to move.
@@ -5366,17 +5416,7 @@ bool TrainController(Train *v, Vehicle *nomove, bool reverse)
 										v->reverse_distance = v->gcache.cached_total_length + (IsDiagonalTrack(TrackdirToTrack(dir)) ? 16 : 8);
 										SetWindowDirty(WC_VEHICLE_VIEW, v->index);
 									}
-									if (out.flags & TRPRF_SPEED_RESTRICTION_SET) {
-										SetBit(v->flags, VRF_PENDING_SPEED_RESTRICTION);
-										auto range = pending_speed_restriction_change_map.equal_range(v->index);
-										for (auto it = range.first; it != range.second; ++it) {
-											if ((uint16) (out.speed_restriction + 0xFFFF) < (uint16) (it->second.new_speed + 0xFFFF)) it->second.new_speed = out.speed_restriction;
-										}
-										uint16 flags = 0;
-										if (IsDiagonalTrack(TrackdirToTrack(dir))) SetBit(flags, PSRCF_DIAGONAL);
-										pending_speed_restriction_change_map.insert({ v->index, { (uint16) (v->gcache.cached_total_length + (HasBit(flags, PSRCF_DIAGONAL) ? 8 : 4)), out.speed_restriction, v->speed_restriction, flags } });
-										if ((uint16) (out.speed_restriction + 0xFFFF) < (uint16) (v->speed_restriction + 0xFFFF)) v->speed_restriction = out.speed_restriction;
-									}
+									HandleTraceRestrictSpeedRestrictionAction(out, v, dir);
 								}
 							}
 						}
@@ -5519,6 +5559,31 @@ bool TrainController(Train *v, Vehicle *nomove, bool reverse)
 					/* Entered wormhole set counters. */
 					v->wait_counter = (TILE_SIZE * simulated_wormhole_signals) - TILE_SIZE;
 					v->tunnel_bridge_signal_num = 0;
+
+					if (v->IsFrontEngine() && IsTunnelBridgeSignalSimulationEntrance(old_tile) && IsTunnelBridgeRestrictedSignal(old_tile)) {
+						const Trackdir trackdir = GetTunnelBridgeEntranceTrackdir(old_tile);
+						const TraceRestrictProgram *prog = GetExistingTraceRestrictProgram(old_tile, TrackdirToTrack(trackdir));
+						if (prog && prog->actions_used_flags & (TRPAUF_SLOT_ACQUIRE | TRPAUF_SLOT_RELEASE_FRONT | TRPAUF_SPEED_RESTRICTION | TRPAUF_CHANGE_COUNTER)) {
+							TraceRestrictProgramResult out;
+							TraceRestrictProgramInput input(old_tile, trackdir, nullptr, nullptr);
+							input.permitted_slot_operations = TRPISP_ACQUIRE | TRPISP_RELEASE_FRONT | TRPISP_CHANGE_COUNTER;
+							prog->Execute(v, input, out);
+							HandleTraceRestrictSpeedRestrictionAction(out, v, trackdir);
+						}
+					}
+
+					if (v->Next() == nullptr && IsTunnelBridgeSignalSimulationEntrance(old_tile) && IsTunnelBridgeRestrictedSignal(old_tile)) {
+						const Trackdir trackdir = GetTunnelBridgeEntranceTrackdir(old_tile);
+						const Track track = TrackdirToTrack(trackdir);
+
+						const TraceRestrictProgram *prog = GetExistingTraceRestrictProgram(old_tile, track);
+						if (prog && prog->actions_used_flags & TRPAUF_SLOT_RELEASE_BACK) {
+							TraceRestrictProgramResult out;
+							TraceRestrictProgramInput input(old_tile, trackdir, nullptr, nullptr);
+							input.permitted_slot_operations = TRPISP_RELEASE_BACK;
+							prog->Execute(first, input, out);
+						}
+					}
 				}
 
 				uint distance = v->wait_counter;
@@ -5534,6 +5599,17 @@ bool TrainController(Train *v, Vehicle *nomove, bool reverse)
 							return false;
 						}
 						leaving = true;
+						if (IsTunnelBridgeRestrictedSignal(gp.new_tile) && IsTunnelBridgeSignalSimulationExit(gp.new_tile)) {
+							const Trackdir trackdir = GetTunnelBridgeExitTrackdir(gp.new_tile);
+							const TraceRestrictProgram *prog = GetExistingTraceRestrictProgram(gp.new_tile, TrackdirToTrack(trackdir));
+							if (prog && prog->actions_used_flags & (TRPAUF_SLOT_ACQUIRE | TRPAUF_SLOT_RELEASE_FRONT | TRPAUF_SPEED_RESTRICTION | TRPAUF_CHANGE_COUNTER)) {
+								TraceRestrictProgramResult out;
+								TraceRestrictProgramInput input(gp.new_tile, trackdir, nullptr, nullptr);
+								input.permitted_slot_operations = TRPISP_ACQUIRE | TRPISP_RELEASE_FRONT | TRPISP_CHANGE_COUNTER;
+								prog->Execute(v, input, out);
+								HandleTraceRestrictSpeedRestrictionAction(out, v, trackdir);
+							}
+						}
 					} else {
 						if (IsTooCloseBehindTrain(v, gp.new_tile, v->wait_counter, distance == 0)) {
 							if (distance == 0) v->wait_counter = 0;
@@ -5765,6 +5841,22 @@ bool TrainController(Train *v, Vehicle *nomove, bool reverse)
 						}
 					}
 				}
+
+				if (IsTileType(gp.old_tile, MP_TUNNELBRIDGE) && IsTunnelBridgeSignalSimulationExit(gp.old_tile) && IsTunnelBridgeRestrictedSignal(gp.old_tile)) {
+					const TrackdirBits rev_tracks = TrackBitsToTrackdirBits(GetTunnelBridgeTrackBits(gp.old_tile)) & DiagdirReachesTrackdirs(ReverseDiagDir(enterdir));
+					const Trackdir rev_trackdir = FindFirstTrackdir(rev_tracks);
+					const Track track = TrackdirToTrack(rev_trackdir);
+
+					if (TrackdirEntersTunnelBridge(gp.old_tile, rev_trackdir)) {
+						const TraceRestrictProgram *prog = GetExistingTraceRestrictProgram(gp.old_tile, track);
+						if (prog && prog->actions_used_flags & TRPAUF_SLOT_RELEASE_BACK) {
+							TraceRestrictProgramResult out;
+							TraceRestrictProgramInput input(gp.old_tile, ReverseTrackdir(rev_trackdir), nullptr, nullptr);
+							input.permitted_slot_operations = TRPISP_RELEASE_BACK;
+							prog->Execute(first, input, out);
+						}
+					}
+				}
 			}
 		}
 
diff --git a/src/tunnelbridge_cmd.cpp b/src/tunnelbridge_cmd.cpp
index 4eafb00084..9d0e8a77b3 100644
--- a/src/tunnelbridge_cmd.cpp
+++ b/src/tunnelbridge_cmd.cpp
@@ -48,6 +48,7 @@
 #include "object_map.h"
 #include "newgrf_station.h"
 #include "station_func.h"
+#include "tracerestrict.h"
 
 #include "table/strings.h"
 #include "table/bridge_land.h"
@@ -1275,6 +1276,8 @@ static CommandCost DoClearTunnel(TileIndex tile, DoCommandFlag flags)
 				c->infrastructure.rail[GetRailType(tile)] -= len * TUNNELBRIDGE_TRACKBIT_FACTOR;
 				if (IsTunnelBridgeWithSignalSimulation(tile)) { // handle tunnel/bridge signals.
 					c->infrastructure.signal -= GetTunnelBridgeSignalSimulationSignalCount(tile, endtile);
+					TraceRestrictNotifySignalRemoval(tile, track);
+					TraceRestrictNotifySignalRemoval(endtile, track);
 				}
 				DirtyCompanyInfrastructureWindows(owner);
 			}
@@ -1410,6 +1413,10 @@ static CommandCost DoClearBridge(TileIndex tile, DoCommandFlag flags)
 		/* Update company infrastructure counts. */
 		if (rail) {
 			SubtractRailTunnelBridgeInfrastructure(tile, endtile);
+			if (IsTunnelBridgeWithSignalSimulation(tile)) {
+				TraceRestrictNotifySignalRemoval(tile, FindFirstTrack(GetAcrossTunnelBridgeTrackBits(tile)));
+				TraceRestrictNotifySignalRemoval(endtile, FindFirstTrack(GetAcrossTunnelBridgeTrackBits(endtile)));
+			}
 		} else if (GetTunnelBridgeTransportType(tile) == TRANSPORT_ROAD) {
 			SubtractRoadTunnelBridgeInfrastructure(tile, endtile);
 			if (RoadLayoutChangeNotificationEnabled(false)) {
@@ -1747,7 +1754,9 @@ static void DrawTunnelBridgeRampSingleSignal(const TileInfo *ti, bool is_green,
 			aspect = 1;
 		}
 	}
-	PalSpriteID sprite = GetCustomSignalSprite(rti, ti->tile, type, variant, aspect).sprite;
+	bool show_restricted = IsTunnelBridgeRestrictedSignal(ti->tile);
+	const CustomSignalSpriteResult result = GetCustomSignalSprite(rti, ti->tile, type, variant, aspect, false, show_restricted);
+	PalSpriteID sprite = result.sprite;
 	bool is_custom_sprite = (sprite.sprite != 0);
 
 	if (is_custom_sprite) {
@@ -1762,7 +1771,26 @@ static void DrawTunnelBridgeRampSingleSignal(const TileInfo *ti, bool is_green,
 		}
 	}
 
-	AddSortableSpriteToDraw(sprite.sprite, sprite.pal, x, y, 1, 1, TILE_HEIGHT, z, false, 0, 0, BB_Z_SEPARATOR);
+	if (is_custom_sprite && show_restricted && _settings_client.gui.show_restricted_signal_default && !result.restricted_valid && variant == SIG_ELECTRIC) {
+		/* Use duplicate sprite block, instead of GRF-specified signals */
+		sprite = { (type == SIGTYPE_NORMAL && variant == SIG_ELECTRIC) ? SPR_DUP_ORIGINAL_SIGNALS_BASE : SPR_DUP_SIGNALS_BASE - 16, PAL_NONE };
+		sprite.sprite += type * 16 + variant * 64 + position * 2 + is_green + (IsSignalSpritePBS(type) ? 64 : 0);
+		is_custom_sprite = false;
+	}
+
+	if (!is_custom_sprite && show_restricted && variant == SIG_ELECTRIC) {
+		if (type == SIGTYPE_PBS || type == SIGTYPE_PBS_ONEWAY) {
+			static const SubSprite lower_part = { -50, -10, 50, 50 };
+			static const SubSprite upper_part = { -50, -50, 50, -11 };
+
+			AddSortableSpriteToDraw(sprite.sprite, SPR_TRACERESTRICT_BASE, x, y, 1, 1, TILE_HEIGHT, z, false, 0, 0, BB_Z_SEPARATOR, &lower_part);
+			AddSortableSpriteToDraw(sprite.sprite,               PAL_NONE, x, y, 1, 1, TILE_HEIGHT, z, false, 0, 0, BB_Z_SEPARATOR, &upper_part);
+		} else {
+			AddSortableSpriteToDraw(sprite.sprite, SPR_TRACERESTRICT_BASE + (type == SIGTYPE_NO_ENTRY ? 0 : 1), x, y, 1, 1, TILE_HEIGHT, z, false, 0, 0, BB_Z_SEPARATOR);
+		}
+	} else {
+		AddSortableSpriteToDraw(sprite.sprite, sprite.pal, x, y, 1, 1, TILE_HEIGHT, z, false, 0, 0, BB_Z_SEPARATOR);
+	}
 }
 
 /* Draws a signal on tunnel / bridge entrance tile. */
@@ -2120,14 +2148,14 @@ static void DrawTile_TunnelBridge(TileInfo *ti, DrawTileProcParams params)
 						image = (SignalOffsets)(image ^ 1);
 					}
 					if (IsTunnelBridgeSignalSimulationEntrance(ti->tile)) {
-						DrawSingleSignal(ti->tile, rti, t, GetTunnelBridgeEntranceSignalState(ti->tile), image, position, SIGTYPE_NORMAL, variant, false, false);
+						DrawSingleSignal(ti->tile, rti, t, GetTunnelBridgeEntranceSignalState(ti->tile), image, position, SIGTYPE_NORMAL, variant, IsTunnelBridgeRestrictedSignal(ti->tile), false);
 					}
 					if (IsTunnelBridgeSignalSimulationExit(ti->tile)) {
 						SignalType type = SIGTYPE_NORMAL;
 						if (IsTunnelBridgePBS(ti->tile)) {
 							type = IsTunnelBridgeSignalSimulationEntrance(ti->tile) ? SIGTYPE_PBS : SIGTYPE_PBS_ONEWAY;
 						}
-						DrawSingleSignal(ti->tile, rti, t, GetTunnelBridgeExitSignalState(ti->tile), (SignalOffsets)(image ^ 1), position ^ 1, type, variant, false, true);
+						DrawSingleSignal(ti->tile, rti, t, GetTunnelBridgeExitSignalState(ti->tile), (SignalOffsets)(image ^ 1), position ^ 1, type, variant, IsTunnelBridgeRestrictedSignal(ti->tile), true);
 					}
 				};
 				switch (t) {
@@ -2524,6 +2552,10 @@ static void GetTileDesc_TunnelBridge(TileIndex tile, TileDesc *td)
 	} else { // IsBridge(tile)
 		td->str = (tt == TRANSPORT_WATER) ? STR_LAI_BRIDGE_DESCRIPTION_AQUEDUCT : IsTunnelBridgeWithSignalSimulation(tile) ? STR_LAI_BRIDGE_DESCRIPTION_RAILROAD_SIGNAL : GetBridgeSpec(GetBridgeType(tile))->transport_name[tt];
 	}
+	if (IsTunnelBridgeWithSignalSimulation(tile) && IsTunnelBridgeRestrictedSignal(tile)) {
+		SetDParamX(td->dparam, 0, td->str);
+		td->str = STR_LAI_RAIL_DESCRIPTION_RESTRICTED_SIGNAL;
+	}
 	td->owner[0] = GetTileOwner(tile);
 
 	if (tt == TRANSPORT_ROAD) {
@@ -2718,6 +2750,24 @@ static void TileLoop_TunnelBridge(TileIndex tile)
 
 static bool ClickTile_TunnelBridge(TileIndex tile)
 {
+	if (_ctrl_pressed && IsTunnelBridgeWithSignalSimulation(tile)) {
+		TrackBits trackbits = TrackStatusToTrackBits(GetTileTrackStatus(tile, TRANSPORT_RAIL, 0));
+
+		if (trackbits & TRACK_BIT_VERT) { // N-S direction
+			trackbits = (_tile_fract_coords.x <= _tile_fract_coords.y) ? TRACK_BIT_RIGHT : TRACK_BIT_LEFT;
+		}
+
+		if (trackbits & TRACK_BIT_HORZ) { // E-W direction
+			trackbits = (_tile_fract_coords.x + _tile_fract_coords.y <= 15) ? TRACK_BIT_UPPER : TRACK_BIT_LOWER;
+		}
+
+		Track track = FindFirstTrack(trackbits);
+		if (HasTrack(GetAcrossTunnelBridgeTrackBits(tile), track)) {
+			ShowTraceRestrictProgramWindow(tile, track);
+			return true;
+		}
+	}
+
 	/* Show vehicles found in tunnel. */
 	if (IsTunnelTile(tile)) {
 		int count = 0;
diff --git a/src/tunnelbridge_map.h b/src/tunnelbridge_map.h
index 1214032c1a..65aafed95b 100644
--- a/src/tunnelbridge_map.h
+++ b/src/tunnelbridge_map.h
@@ -561,6 +561,26 @@ static inline void SetTunnelBridgeSignalSimulationSpacing(TileIndex t, uint spac
 	SB(_me[t].m8, 12, 4, spacing - 1);
 }
 
+/**
+ * Does tunnel/bridge signal tile have "one or more trace restrict mappings present" bit set
+ * @param tile the tile to check
+ */
+static inline bool IsTunnelBridgeRestrictedSignal(TileIndex tile)
+{
+	assert_tile(IsTunnelBridgeWithSignalSimulation(tile), tile);
+	return (bool) GB(_m[tile].m3, 6, 1);
+}
+
+/**
+ * Set tunnel/bridge signal tile "one or more trace restrict mappings present" bit
+ * @param tile the tile to set
+ */
+static inline void SetTunnelBridgeRestrictedSignal(TileIndex tile, bool is_restricted)
+{
+	assert_tile(IsTunnelBridgeWithSignalSimulation(tile), tile);
+	SB(_m[tile].m3, 6, 1, is_restricted);
+}
+
 static inline Trackdir GetTunnelBridgeExitTrackdir(TileIndex t, DiagDirection tunnel_bridge_dir)
 {
 	return TrackEnterdirToTrackdir((Track)FIND_FIRST_BIT(GetAcrossTunnelBridgeTrackBits(t)), ReverseDiagDir(tunnel_bridge_dir));
diff --git a/src/zoning_cmd.cpp b/src/zoning_cmd.cpp
index 68963a3235..e40354e101 100644
--- a/src/zoning_cmd.cpp
+++ b/src/zoning_cmd.cpp
@@ -253,6 +253,9 @@ SpriteID TileZoneCheckTraceRestrictEvaluation(TileIndex tile, Owner owner)
 	if (IsTileType(tile, MP_RAILWAY) && HasSignals(tile) && IsRestrictedSignal(tile)) {
 		return SPR_ZONING_INNER_HIGHLIGHT_RED;
 	}
+	if (IsTunnelBridgeWithSignalSimulation(tile)) {
+		return SPR_ZONING_INNER_HIGHLIGHT_RED;
+	}
 	if (unlikely(HasBit(_misc_debug_flags, MDF_ZONING_RS_WATER_FLOOD_STATE)) && IsNonFloodingWaterTile(tile)) {
 		return SPR_ZONING_INNER_HIGHLIGHT_YELLOW;
 	}