(svn r7759) -Merge: makefile rewrite. This merge features:

 - A proper ./configure, so everything needs to be configured only once, not for every make.
 - Usage of makedepend when available. This greatly reduces the time needed for generating the dependencies.
 - A generator for all project files. There is a single file with sources, which is used to generate Makefiles and the project files for MSVC.
 - Proper support for OSX universal binaries.
 - Object files for non-MSVC compiles are also placed in separate directories, making is faster to switch between debug and release compiles and it does not touch the directory with the source files.
 - Functionality to make a bundle of all needed files for for example a nightly or distribution of a binary with all needed GRFs and language files.

Note: as this merge moves almost all files, it is recommended to make a backup of your working copy before updating your working copy.

1 files changed, 1985 insertions, 0 deletions

diff --git a/src/rail_cmd.c b/src/rail_cmd.c
new file mode 100644
index 000000000..a793bb8a5
--- /dev/null
+++ b/src/rail_cmd.c
@@ -0,0 +1,1985 @@
+/* $Id$ */
+
+#include "stdafx.h"
+#include "openttd.h"
+#include "bridge_map.h"
+#include "debug.h"
+#include "functions.h"
+#include "rail_map.h"
+#include "road_map.h"
+#include "table/sprites.h"
+#include "table/strings.h"
+#include "map.h"
+#include "tile.h"
+#include "town_map.h"
+#include "tunnel_map.h"
+#include "vehicle.h"
+#include "viewport.h"
+#include "command.h"
+#include "pathfind.h"
+#include "engine.h"
+#include "town.h"
+#include "sound.h"
+#include "station.h"
+#include "sprite.h"
+#include "depot.h"
+#include "waypoint.h"
+#include "window.h"
+#include "rail.h"
+#include "railtypes.h" // include table for railtypes
+#include "newgrf.h"
+#include "yapf/yapf.h"
+#include "newgrf_callbacks.h"
+#include "newgrf_station.h"
+#include "train.h"
+
+const byte _track_sloped_sprites[14] = {
+	14, 15, 22, 13,
+	 0, 21, 17, 12,
+	23,  0, 18, 20,
+	19, 16
+};
+
+
+/*         4
+ *     ---------
+ *    |\       /|
+ *    | \    1/ |
+ *    |  \   /  |
+ *    |   \ /   |
+ *  16|    \    |32
+ *    |   / \2  |
+ *    |  /   \  |
+ *    | /     \ |
+ *    |/       \|
+ *     ---------
+ *         8
+ */
+
+
+
+/* MAP2 byte:    abcd???? => Signal On? Same coding as map3lo
+ * MAP3LO byte:  abcd???? => Signal Exists?
+ *               a and b are for diagonals, upper and left,
+ *               one for each direction. (ie a == NE->SW, b ==
+ *               SW->NE, or v.v., I don't know. b and c are
+ *               similar for lower and right.
+ * MAP2 byte:    ????abcd => Type of ground.
+ * MAP3LO byte:  ????abcd => Type of rail.
+ * MAP5:         00abcdef => rail
+ *               01abcdef => rail w/ signals
+ *               10uuuuuu => unused
+ *               11uuuudd => rail depot
+ */
+
+static bool CheckTrackCombination(TileIndex tile, TrackBits to_build, uint flags)
+{
+	TrackBits current; /* The current track layout */
+	TrackBits future; /* The track layout we want to build */
+	_error_message = STR_1001_IMPOSSIBLE_TRACK_COMBINATION;
+
+	if (!IsPlainRailTile(tile)) return false;
+
+	/* So, we have a tile with tracks on it (and possibly signals). Let's see
+	 * what tracks first */
+	current = GetTrackBits(tile);
+	future = current | to_build;
+
+	/* Are we really building something new? */
+	if (current == future) {
+		/* Nothing new is being built */
+		_error_message = STR_1007_ALREADY_BUILT;
+		return false;
+	}
+
+	/* Let's see if we may build this */
+	if (flags & DC_NO_RAIL_OVERLAP || HasSignals(tile)) {
+		/* If we are not allowed to overlap (flag is on for ai players or we have
+		 * signals on the tile), check that */
+		return future == TRACK_BIT_HORZ || future == TRACK_BIT_VERT;
+	} else {
+		/* Normally, we may overlap and any combination is valid */
+		return true;
+	}
+}
+
+
+static const TrackBits _valid_tileh_slopes[][15] = {
+
+// set of normal ones
+{
+	TRACK_BIT_ALL,
+	TRACK_BIT_RIGHT,
+	TRACK_BIT_UPPER,
+	TRACK_BIT_X,
+
+	TRACK_BIT_LEFT,
+	0,
+	TRACK_BIT_Y,
+	TRACK_BIT_LOWER,
+
+	TRACK_BIT_LOWER,
+	TRACK_BIT_Y,
+	0,
+	TRACK_BIT_LEFT,
+
+	TRACK_BIT_X,
+	TRACK_BIT_UPPER,
+	TRACK_BIT_RIGHT,
+},
+
+// allowed rail for an evenly raised platform
+{
+	0,
+	TRACK_BIT_LEFT,
+	TRACK_BIT_LOWER,
+	TRACK_BIT_Y | TRACK_BIT_LOWER | TRACK_BIT_LEFT,
+
+	TRACK_BIT_RIGHT,
+	TRACK_BIT_ALL,
+	TRACK_BIT_X | TRACK_BIT_LOWER | TRACK_BIT_RIGHT,
+	TRACK_BIT_ALL,
+
+	TRACK_BIT_UPPER,
+	TRACK_BIT_X | TRACK_BIT_UPPER | TRACK_BIT_LEFT,
+	TRACK_BIT_ALL,
+	TRACK_BIT_ALL,
+
+	TRACK_BIT_Y | TRACK_BIT_UPPER | TRACK_BIT_RIGHT,
+	TRACK_BIT_ALL,
+	TRACK_BIT_ALL
+}
+};
+
+uint GetRailFoundation(Slope tileh, TrackBits bits)
+{
+	uint i;
+
+	if (!IsSteepSlope(tileh)) {
+		if ((~_valid_tileh_slopes[0][tileh] & bits) == 0) return 0;
+		if ((~_valid_tileh_slopes[1][tileh] & bits) == 0) return tileh;
+	}
+
+	switch (bits) {
+		default: NOT_REACHED();
+		case TRACK_BIT_X: i = 0; break;
+		case TRACK_BIT_Y: i = 1; break;
+		case TRACK_BIT_LEFT:  return 15 + 8 + (tileh == SLOPE_STEEP_W ? 4 : 0);
+		case TRACK_BIT_LOWER: return 15 + 8 + (tileh == SLOPE_STEEP_S ? 5 : 1);
+		case TRACK_BIT_RIGHT: return 15 + 8 + (tileh == SLOPE_STEEP_E ? 6 : 2);
+		case TRACK_BIT_UPPER: return 15 + 8 + (tileh == SLOPE_STEEP_N ? 7 : 3);
+	}
+	switch (tileh) {
+		case SLOPE_W:
+		case SLOPE_STEEP_W: i += 0; break;
+		case SLOPE_S:
+		case SLOPE_STEEP_S: i += 2; break;
+		case SLOPE_E:
+		case SLOPE_STEEP_E: i += 4; break;
+		case SLOPE_N:
+		case SLOPE_STEEP_N: i += 6; break;
+		default: return 0;
+	}
+	return i + 15;
+}
+
+
+static uint32 CheckRailSlope(Slope tileh, TrackBits rail_bits, TrackBits existing, TileIndex tile)
+{
+	if (IsSteepSlope(tileh)) {
+		if (existing == 0) {
+			TrackBits valid = TRACK_BIT_CROSS | (HASBIT(1 << SLOPE_STEEP_W | 1 << SLOPE_STEEP_E, tileh) ? TRACK_BIT_VERT : TRACK_BIT_HORZ);
+			if (valid & rail_bits) return _price.terraform;
+		}
+	} else {
+		rail_bits |= existing;
+
+		// don't allow building on the lower side of a coast
+		if (IsTileType(tile, MP_WATER) &&
+				~_valid_tileh_slopes[1][tileh] & rail_bits) {
+			return_cmd_error(STR_3807_CAN_T_BUILD_ON_WATER);
+		}
+
+		// no special foundation
+		if ((~_valid_tileh_slopes[0][tileh] & rail_bits) == 0)
+			return 0;
+
+		if ((~_valid_tileh_slopes[1][tileh] & rail_bits) == 0 || ( // whole tile is leveled up
+					(rail_bits == TRACK_BIT_X || rail_bits == TRACK_BIT_Y) &&
+					(tileh == SLOPE_W || tileh == SLOPE_S || tileh == SLOPE_E || tileh == SLOPE_N)
+				)) { // partly up
+			if (existing != 0) {
+				return 0;
+			} else if (!_patches.build_on_slopes || _is_old_ai_player) {
+				return_cmd_error(STR_1000_LAND_SLOPED_IN_WRONG_DIRECTION);
+			} else {
+				return _price.terraform;
+			}
+		}
+	}
+	return_cmd_error(STR_1000_LAND_SLOPED_IN_WRONG_DIRECTION);
+}
+
+/* Validate functions for rail building */
+static inline bool ValParamTrackOrientation(Track track) {return IsValidTrack(track);}
+
+/** Build a single piece of rail
+ * @param tile tile  to build on
+ * @param p1 railtype of being built piece (normal, mono, maglev)
+ * @param p2 rail track to build
+ */
+int32 CmdBuildSingleRail(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
+{
+	Slope tileh;
+	RailType railtype;
+	Track track;
+	TrackBits trackbit;
+	int32 cost = 0;
+	int32 ret;
+
+	if (!ValParamRailtype(p1) || !ValParamTrackOrientation(p2)) return CMD_ERROR;
+	railtype = (RailType)p1;
+	track = (Track)p2;
+
+	tileh = GetTileSlope(tile, NULL);
+	trackbit = TrackToTrackBits(track);
+
+	SET_EXPENSES_TYPE(EXPENSES_CONSTRUCTION);
+
+	switch (GetTileType(tile)) {
+		case MP_RAILWAY:
+			if (!CheckTrackCombination(tile, trackbit, flags) ||
+					!EnsureNoVehicle(tile)) {
+				return CMD_ERROR;
+			}
+			if (!IsTileOwner(tile, _current_player) ||
+					!IsCompatibleRail(GetRailType(tile), railtype)) {
+				// Get detailed error message
+				return DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
+			}
+
+			ret = CheckRailSlope(tileh, trackbit, GetTrackBits(tile), tile);
+			if (CmdFailed(ret)) return ret;
+			cost += ret;
+
+			/* If the rail types don't match, try to convert only if engines of
+			 * the present rail type are powered on the new rail type. */
+			if (GetRailType(tile) != railtype && HasPowerOnRail(GetRailType(tile), railtype)) {
+				ret = DoCommand(tile, tile, railtype, flags, CMD_CONVERT_RAIL);
+				if (CmdFailed(ret)) return ret;
+				cost += ret;
+			}
+
+			if (flags & DC_EXEC) {
+				SetRailGroundType(tile, RAIL_GROUND_BARREN);
+				SetTrackBits(tile, GetTrackBits(tile) | trackbit);
+			}
+			break;
+
+		case MP_STREET:
+#define M(x) (1 << (x))
+			/* Level crossings may only be built on these slopes */
+			if (!HASBIT(M(SLOPE_SEN) | M(SLOPE_ENW) | M(SLOPE_NWS) | M(SLOPE_NS) | M(SLOPE_WSE) | M(SLOPE_EW) | M(SLOPE_FLAT), tileh)) {
+				return_cmd_error(STR_1000_LAND_SLOPED_IN_WRONG_DIRECTION);
+			}
+#undef M
+
+			if (!EnsureNoVehicle(tile)) return CMD_ERROR;
+
+			if (GetRoadTileType(tile) == ROAD_TILE_NORMAL) {
+				if (HasRoadWorks(tile)) return_cmd_error(STR_ROAD_WORKS_IN_PROGRESS);
+
+				if ((track == TRACK_X && GetRoadBits(tile) == ROAD_Y) ||
+						(track == TRACK_Y && GetRoadBits(tile) == ROAD_X)) {
+					if (flags & DC_EXEC) {
+						MakeRoadCrossing(tile, GetTileOwner(tile), _current_player, (track == TRACK_X ? AXIS_Y : AXIS_X), railtype, GetTownIndex(tile));
+					}
+					break;
+				}
+			}
+
+			if (IsLevelCrossing(tile) && GetCrossingRailBits(tile) == trackbit) {
+				return_cmd_error(STR_1007_ALREADY_BUILT);
+			}
+			/* FALLTHROUGH */
+
+		default:
+			ret = CheckRailSlope(tileh, trackbit, 0, tile);
+			if (CmdFailed(ret)) return ret;
+			cost += ret;
+
+			ret = DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
+			if (CmdFailed(ret)) return ret;
+			cost += ret;
+
+			if (flags & DC_EXEC) MakeRailNormal(tile, _current_player, trackbit, railtype);
+			break;
+	}
+
+	if (flags & DC_EXEC) {
+		MarkTileDirtyByTile(tile);
+		SetSignalsOnBothDir(tile, track);
+		YapfNotifyTrackLayoutChange(tile, track);
+	}
+
+	return cost + _price.build_rail;
+}
+
+/** Remove a single piece of track
+ * @param tile tile to remove track from
+ * @param p1 unused
+ * @param p2 rail orientation
+ */
+int32 CmdRemoveSingleRail(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
+{
+	Track track = (Track)p2;
+	TrackBits trackbit;
+	int32 cost = _price.remove_rail;
+	bool crossing = false;
+
+	if (!ValParamTrackOrientation(p2)) return CMD_ERROR;
+	trackbit = TrackToTrackBits(track);
+
+	SET_EXPENSES_TYPE(EXPENSES_CONSTRUCTION);
+
+	switch (GetTileType(tile)) {
+		case MP_STREET: {
+			if (!IsLevelCrossing(tile) ||
+					GetCrossingRailBits(tile) != trackbit ||
+					(_current_player != OWNER_WATER && !CheckTileOwnership(tile)) ||
+					!EnsureNoVehicle(tile)) {
+				return CMD_ERROR;
+			}
+
+			if (flags & DC_EXEC) {
+				MakeRoadNormal(tile, GetCrossingRoadOwner(tile), GetCrossingRoadBits(tile), GetTownIndex(tile));
+			}
+			break;
+		}
+
+		case MP_RAILWAY: {
+			TrackBits present;
+
+			if (!IsPlainRailTile(tile) ||
+					(_current_player != OWNER_WATER && !CheckTileOwnership(tile)) ||
+					!EnsureNoVehicle(tile)) {
+				return CMD_ERROR;
+			}
+
+			present = GetTrackBits(tile);
+			if ((present & trackbit) == 0) return CMD_ERROR;
+			if (present == (TRACK_BIT_X | TRACK_BIT_Y)) crossing = true;
+
+			/* Charge extra to remove signals on the track, if they are there */
+			if (HasSignalOnTrack(tile, track))
+				cost += DoCommand(tile, track, 0, flags, CMD_REMOVE_SIGNALS);
+
+			if (flags & DC_EXEC) {
+				present ^= trackbit;
+				if (present == 0) {
+					DoClearSquare(tile);
+				} else {
+					SetTrackBits(tile, present);
+				}
+			}
+			break;
+		}
+
+		default: return CMD_ERROR;
+	}
+
+	if (flags & DC_EXEC) {
+		MarkTileDirtyByTile(tile);
+		if (crossing) {
+			/* crossing is set when only TRACK_BIT_X and TRACK_BIT_Y are set. As we
+			 * are removing one of these pieces, we'll need to update signals for
+			 * both directions explicitly, as after the track is removed it won't
+			 * 'connect' with the other piece. */
+			SetSignalsOnBothDir(tile, TRACK_X);
+			SetSignalsOnBothDir(tile, TRACK_Y);
+			YapfNotifyTrackLayoutChange(tile, TRACK_X);
+			YapfNotifyTrackLayoutChange(tile, TRACK_Y);
+		} else {
+			SetSignalsOnBothDir(tile, track);
+			YapfNotifyTrackLayoutChange(tile, track);
+		}
+	}
+
+	return cost;
+}
+
+
+static const TileIndexDiffC _trackdelta[] = {
+	{ -1,  0 }, {  0,  1 }, { -1,  0 }, {  0,  1 }, {  1,  0 }, {  0,  1 },
+	{  0,  0 },
+	{  0,  0 },
+	{  1,  0 }, {  0, -1 }, {  0, -1 }, {  1,  0 }, {  0, -1 }, { -1,  0 },
+	{  0,  0 },
+	{  0,  0 }
+};
+
+
+static int32 ValidateAutoDrag(Trackdir *trackdir, TileIndex start, TileIndex end)
+{
+	int x = TileX(start);
+	int y = TileY(start);
+	int ex = TileX(end);
+	int ey = TileY(end);
+	int dx, dy, trdx, trdy;
+
+	if (!ValParamTrackOrientation(*trackdir)) return CMD_ERROR;
+
+	// calculate delta x,y from start to end tile
+	dx = ex - x;
+	dy = ey - y;
+
+	// calculate delta x,y for the first direction
+	trdx = _trackdelta[*trackdir].x;
+	trdy = _trackdelta[*trackdir].y;
+
+	if (!IsDiagonalTrackdir(*trackdir)) {
+		trdx += _trackdelta[*trackdir ^ 1].x;
+		trdy += _trackdelta[*trackdir ^ 1].y;
+	}
+
+	// validate the direction
+	while (
+		(trdx <= 0 && dx > 0) ||
+		(trdx >= 0 && dx < 0) ||
+		(trdy <= 0 && dy > 0) ||
+		(trdy >= 0 && dy < 0)
+	) {
+		if (!HASBIT(*trackdir, 3)) { // first direction is invalid, try the other
+			SETBIT(*trackdir, 3); // reverse the direction
+			trdx = -trdx;
+			trdy = -trdy;
+		} else { // other direction is invalid too, invalid drag
+			return CMD_ERROR;
+		}
+	}
+
+	// (for diagonal tracks, this is already made sure of by above test), but:
+	// for non-diagonal tracks, check if the start and end tile are on 1 line
+	if (!IsDiagonalTrackdir(*trackdir)) {
+		trdx = _trackdelta[*trackdir].x;
+		trdy = _trackdelta[*trackdir].y;
+		if (abs(dx) != abs(dy) && abs(dx) + abs(trdy) != abs(dy) + abs(trdx))
+			return CMD_ERROR;
+	}
+
+	return 0;
+}
+
+/** Build a stretch of railroad tracks.
+ * @param tile start tile of drag
+ * @param p1 end tile of drag
+ * @param p2 various bitstuffed elements
+ * - p2 = (bit 0-3) - railroad type normal/maglev (0 = normal, 1 = mono, 2 = maglev)
+ * - p2 = (bit 4-6) - track-orientation, valid values: 0-5 (Track enum)
+ * - p2 = (bit 7)   - 0 = build, 1 = remove tracks
+ */
+static int32 CmdRailTrackHelper(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
+{
+	int32 ret, total_cost = 0;
+	Track track = (Track)GB(p2, 4, 3);
+	Trackdir trackdir;
+	byte mode = HASBIT(p2, 7);
+	RailType railtype = (RailType)GB(p2, 0, 4);
+	TileIndex end_tile;
+
+	if (!ValParamRailtype(railtype) || !ValParamTrackOrientation(track)) return CMD_ERROR;
+	if (p1 >= MapSize()) return CMD_ERROR;
+	end_tile = p1;
+	trackdir = TrackToTrackdir(track);
+
+	SET_EXPENSES_TYPE(EXPENSES_CONSTRUCTION);
+
+	if (CmdFailed(ValidateAutoDrag(&trackdir, tile, end_tile))) return CMD_ERROR;
+
+	if (flags & DC_EXEC) SndPlayTileFx(SND_20_SPLAT_2, tile);
+
+	for (;;) {
+		ret = DoCommand(tile, railtype, TrackdirToTrack(trackdir), flags, (mode == 0) ? CMD_BUILD_SINGLE_RAIL : CMD_REMOVE_SINGLE_RAIL);
+
+		if (CmdFailed(ret)) {
+			if ((_error_message != STR_1007_ALREADY_BUILT) && (mode == 0)) break;
+			_error_message = INVALID_STRING_ID;
+		} else {
+			total_cost += ret;
+		}
+
+		if (tile == end_tile) break;
+
+		tile += ToTileIndexDiff(_trackdelta[trackdir]);
+
+		// toggle railbit for the non-diagonal tracks
+		if (!IsDiagonalTrackdir(trackdir)) trackdir ^= 1;
+	}
+
+	return (total_cost == 0) ? CMD_ERROR : total_cost;
+}
+
+/** Build rail on a stretch of track.
+ * Stub for the unified rail builder/remover
+ * @see CmdRailTrackHelper
+ */
+int32 CmdBuildRailroadTrack(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
+{
+	return CmdRailTrackHelper(tile, flags, p1, CLRBIT(p2, 7));
+}
+
+/** Build rail on a stretch of track.
+ * Stub for the unified rail builder/remover
+ * @see CmdRailTrackHelper
+ */
+int32 CmdRemoveRailroadTrack(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
+{
+	return CmdRailTrackHelper(tile, flags, p1, SETBIT(p2, 7));
+}
+
+/** Build a train depot
+ * @param tile position of the train depot
+ * @param p1 rail type
+ * @param p2 entrance direction (DiagDirection)
+ *
+ * @todo When checking for the tile slope,
+ * distingush between "Flat land required" and "land sloped in wrong direction"
+ */
+int32 CmdBuildTrainDepot(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
+{
+	Depot *d;
+	int32 cost, ret;
+	Slope tileh;
+
+	SET_EXPENSES_TYPE(EXPENSES_CONSTRUCTION);
+
+	if (!EnsureNoVehicle(tile)) return CMD_ERROR;
+	/* check railtype and valid direction for depot (0 through 3), 4 in total */
+	if (!ValParamRailtype(p1) || p2 > 3) return CMD_ERROR;
+
+	tileh = GetTileSlope(tile, NULL);
+
+	/* Prohibit construction if
+	 * The tile is non-flat AND
+	 * 1) The AI is "old-school"
+	 * 2) build-on-slopes is disabled
+	 * 3) the tile is steep i.e. spans two height levels
+	 * 4) the exit points in the wrong direction
+	 */
+
+	if (tileh != SLOPE_FLAT && (
+				_is_old_ai_player ||
+				!_patches.build_on_slopes ||
+				IsSteepSlope(tileh) ||
+				!CanBuildDepotByTileh(p2, tileh)
+			)) {
+		return_cmd_error(STR_0007_FLAT_LAND_REQUIRED);
+	}
+
+	ret = DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
+	if (CmdFailed(ret)) return CMD_ERROR;
+	cost = ret;
+
+	if (MayHaveBridgeAbove(tile) && IsBridgeAbove(tile)) return_cmd_error(STR_5007_MUST_DEMOLISH_BRIDGE_FIRST);
+
+	d = AllocateDepot();
+	if (d == NULL) return CMD_ERROR;
+
+	if (flags & DC_EXEC) {
+		MakeRailDepot(tile, _current_player, p2, p1);
+		MarkTileDirtyByTile(tile);
+
+		d->xy = tile;
+		d->town_index = ClosestTownFromTile(tile, (uint)-1)->index;
+
+		UpdateSignalsOnSegment(tile, p2);
+		YapfNotifyTrackLayoutChange(tile, TrackdirToTrack(DiagdirToDiagTrackdir(p2)));
+	}
+
+	return cost + _price.build_train_depot;
+}
+
+/** Build signals, alternate between double/single, signal/semaphore,
+ * pre/exit/combo-signals, and what-else not
+ * @param tile tile where to build the signals
+ * @param p1 various bitstuffed elements
+ * - p1 = (bit 0-2) - track-orientation, valid values: 0-5 (Track enum)
+ * - p1 = (bit 3)   - choose semaphores/signals or cycle normal/pre/exit/combo depending on context
+ * @param p2 used for CmdBuildManySignals() to copy direction of first signal
+ * TODO: p2 should be replaced by two bits for "along" and "against" the track.
+ */
+int32 CmdBuildSingleSignal(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
+{
+	SignalVariant sigvar;
+	bool pre_signal;
+	Track track = (Track)(p1 & 0x7);
+	int32 cost;
+
+	// Same bit, used in different contexts
+	sigvar = HASBIT(p1, 3) ? SIG_SEMAPHORE : SIG_ELECTRIC;
+	pre_signal = HASBIT(p1, 3);
+
+	if (!ValParamTrackOrientation(track) || !IsTileType(tile, MP_RAILWAY) || !EnsureNoVehicle(tile))
+		return CMD_ERROR;
+
+	/* Protect against invalid signal copying */
+	if (p2 != 0 && (p2 & SignalOnTrack(track)) == 0) return CMD_ERROR;
+
+	/* You can only build signals on plain rail tiles, and the selected track must exist */
+	if (!IsPlainRailTile(tile) || !HasTrack(tile, track)) return CMD_ERROR;
+
+	if (!CheckTileOwnership(tile)) return CMD_ERROR;
+
+	_error_message = STR_1005_NO_SUITABLE_RAILROAD_TRACK;
+
+	{
+		/* See if this is a valid track combination for signals, (ie, no overlap) */
+		TrackBits trackbits = GetTrackBits(tile);
+		if (KILL_FIRST_BIT(trackbits) != 0 && /* More than one track present */
+				trackbits != TRACK_BIT_HORZ &&
+				trackbits != TRACK_BIT_VERT) {
+			return CMD_ERROR;
+		}
+	}
+
+	SET_EXPENSES_TYPE(EXPENSES_CONSTRUCTION);
+
+	if (!HasSignalOnTrack(tile, track)) {
+		// build new signals
+		cost = _price.build_signals;
+	} else {
+		if (p2 != 0 && sigvar != GetSignalVariant(tile)) {
+			// convert signals <-> semaphores
+			cost = _price.build_signals + _price.remove_signals;
+		} else {
+			// it is free to change orientation/pre-exit-combo signals
+			cost = 0;
+		}
+	}
+
+	if (flags & DC_EXEC) {
+		if (!HasSignals(tile)) {
+			// there are no signals at all on this tile yet
+			_m[tile].m5 |= RAIL_TILE_SIGNALS; // change into signals
+			_m[tile].m2 |= 0xF0;              // all signals are on
+			_m[tile].m3 &= ~0xF0;          // no signals built by default
+			SetSignalType(tile, SIGTYPE_NORMAL);
+			SetSignalVariant(tile, sigvar);
+		}
+
+		if (p2 == 0) {
+			if (!HasSignalOnTrack(tile, track)) {
+				// build new signals
+				_m[tile].m3 |= SignalOnTrack(track);
+			} else {
+				if (pre_signal) {
+					// cycle between normal -> pre -> exit -> combo -> ...
+					SignalType type = GetSignalType(tile);
+
+					SetSignalType(tile, type == SIGTYPE_COMBO ? SIGTYPE_NORMAL : type + 1);
+				} else {
+					CycleSignalSide(tile, track);
+				}
+			}
+		} else {
+			/* If CmdBuildManySignals is called with copying signals, just copy the
+			 * direction of the first signal given as parameter by CmdBuildManySignals */
+			_m[tile].m3 &= ~SignalOnTrack(track);
+			_m[tile].m3 |= p2 & SignalOnTrack(track);
+			SetSignalVariant(tile, sigvar);
+		}
+
+		MarkTileDirtyByTile(tile);
+		SetSignalsOnBothDir(tile, track);
+		YapfNotifyTrackLayoutChange(tile, track);
+	}
+
+	return cost;
+}
+
+/** Build many signals by dragging; AutoSignals
+ * @param tile start tile of drag
+ * @param p1  end tile of drag
+ * @param p2 various bitstuffed elements
+ * - p2 = (bit  0)    - 0 = build, 1 = remove signals
+ * - p2 = (bit  3)    - 0 = signals, 1 = semaphores
+ * - p2 = (bit  4- 6) - track-orientation, valid values: 0-5 (Track enum)
+ * - p2 = (bit 24-31) - user defined signals_density
+ */
+static int32 CmdSignalTrackHelper(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
+{
+	int32 ret, total_cost, signal_ctr;
+	byte signals;
+	bool error = true;
+	TileIndex end_tile;
+
+	int mode = p2 & 0x1;
+	Track track = GB(p2, 4, 3);
+	Trackdir trackdir = TrackToTrackdir(track);
+	byte semaphores = (HASBIT(p2, 3) ? 8 : 0);
+	byte signal_density = (p2 >> 24);
+
+	if (p1 >= MapSize()) return CMD_ERROR;
+	end_tile = p1;
+	if (signal_density == 0 || signal_density > 20) return CMD_ERROR;
+
+	if (!IsTileType(tile, MP_RAILWAY)) return CMD_ERROR;
+
+	SET_EXPENSES_TYPE(EXPENSES_CONSTRUCTION);
+
+	/* for vertical/horizontal tracks, double the given signals density
+	 * since the original amount will be too dense (shorter tracks) */
+	if (!IsDiagonalTrack(track)) signal_density *= 2;
+
+	if (CmdFailed(ValidateAutoDrag(&trackdir, tile, end_tile))) return CMD_ERROR;
+
+	track = TrackdirToTrack(trackdir); /* trackdir might have changed, keep track in sync */
+
+	// copy the signal-style of the first rail-piece if existing
+	if (HasSignals(tile)) {
+		signals = _m[tile].m3 & SignalOnTrack(track);
+		if (signals == 0) signals = SignalOnTrack(track); /* Can this actually occur? */
+
+		// copy signal/semaphores style (independent of CTRL)
+		semaphores = (GetSignalVariant(tile) == SIG_ELECTRIC ? 0 : 8);
+	} else { // no signals exist, drag a two-way signal stretch
+		signals = SignalOnTrack(track);
+	}
+
+	/* signal_ctr         - amount of tiles already processed
+	 * signals_density    - patch setting to put signal on every Nth tile (double space on |, -- tracks)
+	 **********
+	 * trackdir   - trackdir to build with autorail
+	 * semaphores - semaphores or signals
+	 * signals    - is there a signal/semaphore on the first tile, copy its style (two-way/single-way)
+	 *              and convert all others to semaphore/signal
+	 * mode       - 1 remove signals, 0 build signals */
+	signal_ctr = total_cost = 0;
+	for (;;) {
+		// only build/remove signals with the specified density
+		if (signal_ctr % signal_density == 0) {
+			ret = DoCommand(tile, TrackdirToTrack(trackdir) | semaphores, signals, flags, (mode == 1) ? CMD_REMOVE_SIGNALS : CMD_BUILD_SIGNALS);
+
+			/* Be user-friendly and try placing signals as much as possible */
+			if (!CmdFailed(ret)) {
+				error = false;
+				total_cost += ret;
+			}
+		}
+
+		if (tile == end_tile) break;
+
+		tile += ToTileIndexDiff(_trackdelta[trackdir]);
+		signal_ctr++;
+
+		// toggle railbit for the non-diagonal tracks (|, -- tracks)
+		if (!IsDiagonalTrackdir(trackdir)) trackdir ^= 1;
+	}
+
+	return error ? CMD_ERROR : total_cost;
+}
+
+/** Build signals on a stretch of track.
+ * Stub for the unified signal builder/remover
+ * @see CmdSignalTrackHelper
+ */
+int32 CmdBuildSignalTrack(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
+{
+	return CmdSignalTrackHelper(tile, flags, p1, p2);
+}
+
+/** Remove signals
+ * @param tile coordinates where signal is being deleted from
+ * @param p1 track to remove signal from (Track enum)
+ */
+int32 CmdRemoveSingleSignal(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
+{
+	Track track = (Track)(p1 & 0x7);
+
+	if (!ValParamTrackOrientation(track) ||
+			!IsTileType(tile, MP_RAILWAY) ||
+			!EnsureNoVehicle(tile) ||
+			!HasSignalOnTrack(tile, track)) {
+		return CMD_ERROR;
+	}
+
+	/* Only water can remove signals from anyone */
+	if (_current_player != OWNER_WATER && !CheckTileOwnership(tile)) return CMD_ERROR;
+
+	SET_EXPENSES_TYPE(EXPENSES_CONSTRUCTION);
+
+	/* Do it? */
+	if (flags & DC_EXEC) {
+		_m[tile].m3 &= ~SignalOnTrack(track);
+
+		/* removed last signal from tile? */
+		if (GB(_m[tile].m3, 4, 4) == 0) {
+			SB(_m[tile].m2, 4, 4, 0);
+			SB(_m[tile].m5, 6, 2, RAIL_TILE_NORMAL >> 6); // XXX >> because the constant is meant for direct application, not use with SB
+			SetSignalVariant(tile, SIG_ELECTRIC); // remove any possible semaphores
+		}
+
+		SetSignalsOnBothDir(tile, track);
+		YapfNotifyTrackLayoutChange(tile, track);
+
+		MarkTileDirtyByTile(tile);
+	}
+
+	return _price.remove_signals;
+}
+
+/** Remove signals on a stretch of track.
+ * Stub for the unified signal builder/remover
+ * @see CmdSignalTrackHelper
+ */
+int32 CmdRemoveSignalTrack(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
+{
+	return CmdSignalTrackHelper(tile, flags, p1, SETBIT(p2, 0));
+}
+
+typedef int32 DoConvertRailProc(TileIndex tile, RailType totype, bool exec);
+
+static int32 DoConvertRail(TileIndex tile, RailType totype, bool exec)
+{
+	if (!CheckTileOwnership(tile)) return CMD_ERROR;
+
+	if (!EnsureNoVehicle(tile) && (!IsCompatibleRail(GetRailType(tile), totype) || IsPlainRailTile(tile))) return CMD_ERROR;
+
+	// tile is already of requested type?
+	if (GetRailType(tile) == totype) return CMD_ERROR;
+
+	// 'hidden' elrails can't be downgraded to normal rail when elrails are disabled
+	if (_patches.disable_elrails && totype == RAILTYPE_RAIL && GetRailType(tile) == RAILTYPE_ELECTRIC) return CMD_ERROR;
+
+	// change type.
+	if (exec) {
+		TrackBits tracks;
+		SetRailType(tile, totype);
+		MarkTileDirtyByTile(tile);
+
+		// notify YAPF about the track layout change
+		for (tracks = GetTrackBits(tile); tracks != TRACK_BIT_NONE; tracks = KILL_FIRST_BIT(tracks))
+			YapfNotifyTrackLayoutChange(tile, FIND_FIRST_BIT(tracks));
+
+		if (IsTileDepotType(tile, TRANSPORT_RAIL)) {
+			Vehicle *v;
+
+			/* Update build vehicle window related to this depot */
+			InvalidateWindowData(WC_BUILD_VEHICLE, tile);
+
+			/* update power of trains in this depot */
+			FOR_ALL_VEHICLES(v) {
+				if (v->type == VEH_Train && IsFrontEngine(v) && v->tile == tile && v->u.rail.track == 0x80) {
+					TrainPowerChanged(v);
+				}
+			}
+		}
+	}
+
+	return _price.build_rail / 2;
+}
+
+extern int32 DoConvertStationRail(TileIndex tile, RailType totype, bool exec);
+extern int32 DoConvertStreetRail(TileIndex tile, RailType totype, bool exec);
+extern int32 DoConvertTunnelBridgeRail(TileIndex tile, RailType totype, bool exec);
+
+/** Convert one rail type to the other. You can convert normal rail to
+ * monorail/maglev easily or vice-versa.
+ * @param tile end tile of rail conversion drag
+ * @param p1 start tile of drag
+ * @param p2 new railtype to convert to
+ */
+int32 CmdConvertRail(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
+{
+	int32 ret, cost, money;
+	int ex;
+	int ey;
+	int sx, sy, x, y;
+
+	SET_EXPENSES_TYPE(EXPENSES_CONSTRUCTION);
+
+	if (!ValParamRailtype(p2)) return CMD_ERROR;
+	if (p1 >= MapSize()) return CMD_ERROR;
+
+	// make sure sx,sy are smaller than ex,ey
+	ex = TileX(tile);
+	ey = TileY(tile);
+	sx = TileX(p1);
+	sy = TileY(p1);
+	if (ex < sx) intswap(ex, sx);
+	if (ey < sy) intswap(ey, sy);
+
+	money = GetAvailableMoneyForCommand();
+	cost = 0;
+	ret = 0;
+
+	for (x = sx; x <= ex; ++x) {
+		for (y = sy; y <= ey; ++y) {
+			TileIndex tile = TileXY(x, y);
+			DoConvertRailProc* proc;
+
+			switch (GetTileType(tile)) {
+				case MP_RAILWAY:      proc = DoConvertRail;             break;
+				case MP_STATION:      proc = DoConvertStationRail;      break;
+				case MP_STREET:       proc = DoConvertStreetRail;       break;
+				case MP_TUNNELBRIDGE: proc = DoConvertTunnelBridgeRail; break;
+				default: continue;
+			}
+
+			ret = proc(tile, p2, false);
+			if (CmdFailed(ret)) continue;
+			cost += ret;
+
+			if (flags & DC_EXEC) {
+				money -= ret;
+				if (money < 0) {
+					_additional_cash_required = ret;
+					return cost - ret;
+				}
+				proc(tile, p2, true);
+			}
+		}
+	}
+
+	return (cost == 0) ? ret : cost;
+}
+
+static int32 RemoveTrainDepot(TileIndex tile, uint32 flags)
+{
+	if (!CheckTileOwnership(tile) && _current_player != OWNER_WATER)
+		return CMD_ERROR;
+
+	if (!EnsureNoVehicle(tile))
+		return CMD_ERROR;
+
+	if (flags & DC_EXEC) {
+		DiagDirection dir = GetRailDepotDirection(tile);
+
+		DeleteDepot(GetDepotByTile(tile));
+		UpdateSignalsOnSegment(tile, dir);
+		YapfNotifyTrackLayoutChange(tile, TrackdirToTrack(DiagdirToDiagTrackdir(dir)));
+	}
+
+	return _price.remove_train_depot;
+}
+
+static int32 ClearTile_Track(TileIndex tile, byte flags)
+{
+	int32 cost;
+	int32 ret;
+
+	if (flags & DC_AUTO) {
+		if (!IsTileOwner(tile, _current_player))
+			return_cmd_error(STR_1024_AREA_IS_OWNED_BY_ANOTHER);
+
+		if (IsPlainRailTile(tile)) {
+			return_cmd_error(STR_1008_MUST_REMOVE_RAILROAD_TRACK);
+		} else {
+			return_cmd_error(STR_2004_BUILDING_MUST_BE_DEMOLISHED);
+		}
+	}
+
+	cost = 0;
+
+	switch (GetRailTileType(tile)) {
+		case RAIL_TILE_SIGNALS:
+		case RAIL_TILE_NORMAL: {
+			TrackBits tracks = GetTrackBits(tile);
+			uint i;
+
+			for_each_bit (i, tracks) {
+				ret = DoCommand(tile, 0, i, flags, CMD_REMOVE_SINGLE_RAIL);
+				if (CmdFailed(ret)) return CMD_ERROR;
+				cost += ret;
+			}
+			return cost;
+		}
+
+		case RAIL_TILE_DEPOT_WAYPOINT:
+			if (GetRailTileSubtype(tile) == RAIL_SUBTYPE_DEPOT) {
+				return RemoveTrainDepot(tile, flags);
+			} else {
+				return RemoveTrainWaypoint(tile, flags, false);
+			}
+
+		default:
+			return CMD_ERROR;
+	}
+}
+
+#include "table/track_land.h"
+
+static void DrawSingleSignal(TileIndex tile, byte condition, uint image, uint pos)
+{
+	bool side = _opt.road_side & _patches.signal_side;
+	static const Point SignalPositions[2][12] = {
+		{      /* Signals on the left side */
+		/*  LEFT      LEFT      RIGHT     RIGHT     UPPER     UPPER */
+			{ 8,  5}, {14,  1}, { 1, 14}, { 9, 11}, { 1,  0}, { 3, 10},
+		/*  LOWER     LOWER     X         X         Y         Y     */
+			{11,  4}, {14, 14}, {11,  3}, { 4, 13}, { 3,  4}, {11, 13}
+		}, {   /* Signals on the right side */
+		/*  LEFT      LEFT      RIGHT     RIGHT     UPPER     UPPER */
+			{14,  1}, {12, 10}, { 4,  6}, { 1, 14}, {10,  4}, { 0,  1},
+		/*  LOWER     LOWER     X         X         Y         Y     */
+			{14, 14}, { 5, 12}, {11, 13}, { 4,  3}, {13,  4}, { 3, 11}
+		}
+	};
+
+	static const SpriteID SignalBase[2][2][4] = {
+		{    /* Signals on left side */
+			{  0x4FB, 0x1323, 0x1333, 0x1343}, /* light signals */
+			{ 0x1353, 0x1363, 0x1373, 0x1383}  /* semaphores    */
+		}, { /* Signals on right side */
+			{  0x4FB, 0x1323, 0x1333, 0x1343}, /* light signals */
+			{ 0x1446, 0x1456, 0x1466, 0x1476}  /* semaphores    */
+		/*         |       |       |       |     */
+		/*    normal,  entry,   exit,  combo     */
+		}
+	};
+
+	uint x = TileX(tile) * TILE_SIZE + SignalPositions[side][pos].x;
+	uint y = TileY(tile) * TILE_SIZE + SignalPositions[side][pos].y;
+
+	SpriteID sprite;
+
+	/* _signal_base is set by our NewGRF Action 5 loader. If it is 0 then we
+	 * just draw the standard signals, else we get the offset from _signal_base
+	 * and draw that sprite. All the signal sprites are loaded sequentially. */
+	if (_signal_base == 0 || (GetSignalType(tile) == 0 && GetSignalVariant(tile) == SIG_ELECTRIC)) {
+		sprite = SignalBase[side][GetSignalVariant(tile)][GetSignalType(tile)] + image + condition;
+	} else {
+		sprite = _signal_base + (GetSignalType(tile) - 1) * 16 + GetSignalVariant(tile) * 64 + image + condition;
+	}
+
+	AddSortableSpriteToDraw(sprite, x, y, 1, 1, 10, GetSlopeZ(x,y));
+}
+
+static uint32 _drawtile_track_palette;
+
+
+static void DrawTrackFence_NW(const TileInfo *ti)
+{
+	uint32 image = 0x515;
+	if (ti->tileh != SLOPE_FLAT) image = (ti->tileh & SLOPE_S) ? 0x519 : 0x51B;
+	AddSortableSpriteToDraw(image | _drawtile_track_palette,
+		ti->x, ti->y + 1, 16, 1, 4, ti->z);
+}
+
+static void DrawTrackFence_SE(const TileInfo *ti)
+{
+	uint32 image = 0x515;
+	if (ti->tileh != SLOPE_FLAT) image = (ti->tileh & SLOPE_S) ? 0x519 : 0x51B;
+	AddSortableSpriteToDraw(image | _drawtile_track_palette,
+		ti->x, ti->y + TILE_SIZE - 1, 16, 1, 4, ti->z);
+}
+
+static void DrawTrackFence_NW_SE(const TileInfo *ti)
+{
+	DrawTrackFence_NW(ti);
+	DrawTrackFence_SE(ti);
+}
+
+static void DrawTrackFence_NE(const TileInfo *ti)
+{
+	uint32 image = 0x516;
+	if (ti->tileh != SLOPE_FLAT) image = (ti->tileh & SLOPE_S) ? 0x51A : 0x51C;
+	AddSortableSpriteToDraw(image | _drawtile_track_palette,
+		ti->x + 1, ti->y, 1, 16, 4, ti->z);
+}
+
+static void DrawTrackFence_SW(const TileInfo *ti)
+{
+	uint32 image = 0x516;
+	if (ti->tileh != SLOPE_FLAT) image = (ti->tileh & SLOPE_S) ? 0x51A : 0x51C;
+	AddSortableSpriteToDraw(image | _drawtile_track_palette,
+		ti->x + TILE_SIZE - 1, ti->y, 1, 16, 4, ti->z);
+}
+
+static void DrawTrackFence_NE_SW(const TileInfo *ti)
+{
+	DrawTrackFence_NE(ti);
+	DrawTrackFence_SW(ti);
+}
+
+static void DrawTrackFence_NS_1(const TileInfo *ti)
+{
+	int z = ti->z;
+	if (ti->tileh & SLOPE_W) z += TILE_HEIGHT;
+	AddSortableSpriteToDraw(0x517 | _drawtile_track_palette,
+		ti->x + TILE_SIZE / 2, ti->y + TILE_SIZE / 2, 1, 1, 4, z);
+}
+
+static void DrawTrackFence_NS_2(const TileInfo *ti)
+{
+	int z = ti->z;
+	if (ti->tileh & SLOPE_E) z += TILE_HEIGHT;
+	AddSortableSpriteToDraw(0x517 | _drawtile_track_palette,
+		ti->x + TILE_SIZE / 2, ti->y + TILE_SIZE / 2, 1, 1, 4, z);
+}
+
+static void DrawTrackFence_WE_1(const TileInfo *ti)
+{
+	int z = ti->z;
+	if (ti->tileh & SLOPE_N) z += TILE_HEIGHT;
+	AddSortableSpriteToDraw(0x518 | _drawtile_track_palette,
+		ti->x + TILE_SIZE / 2, ti->y + TILE_SIZE / 2, 1, 1, 4, z);
+}
+
+static void DrawTrackFence_WE_2(const TileInfo *ti)
+{
+	int z = ti->z;
+	if (ti->tileh & SLOPE_S) z += TILE_HEIGHT;
+	AddSortableSpriteToDraw(0x518 | _drawtile_track_palette,
+		ti->x + TILE_SIZE / 2, ti->y + TILE_SIZE / 2, 1, 1, 4, z);
+}
+
+
+static void DrawTrackDetails(const TileInfo* ti)
+{
+	switch (GetRailGroundType(ti->tile)) {
+		case RAIL_GROUND_FENCE_NW:     DrawTrackFence_NW(ti);    break;
+		case RAIL_GROUND_FENCE_SE:     DrawTrackFence_SE(ti);    break;
+		case RAIL_GROUND_FENCE_SENW:   DrawTrackFence_NW_SE(ti); break;
+		case RAIL_GROUND_FENCE_NE:     DrawTrackFence_NE(ti);    break;
+		case RAIL_GROUND_FENCE_SW:     DrawTrackFence_SW(ti);    break;
+		case RAIL_GROUND_FENCE_NESW:   DrawTrackFence_NE_SW(ti); break;
+		case RAIL_GROUND_FENCE_VERT1:  DrawTrackFence_NS_1(ti);  break;
+		case RAIL_GROUND_FENCE_VERT2:  DrawTrackFence_NS_2(ti);  break;
+		case RAIL_GROUND_FENCE_HORIZ1: DrawTrackFence_WE_1(ti);  break;
+		case RAIL_GROUND_FENCE_HORIZ2: DrawTrackFence_WE_2(ti);  break;
+		default: break;
+	}
+}
+
+
+/**
+ * Draw ground sprite and track bits
+ * @param ti TileInfo
+ * @param track TrackBits to draw
+ * @param earth Draw as earth
+ * @param snow Draw as snow
+ * @param flat Always draw foundation
+ */
+static void DrawTrackBits(TileInfo* ti, TrackBits track)
+{
+	const RailtypeInfo *rti = GetRailTypeInfo(GetRailType(ti->tile));
+	PalSpriteID image;
+	bool junction = false;
+
+	// Select the sprite to use.
+	(image = rti->base_sprites.track_y, track == TRACK_BIT_Y) ||
+	(image++,                           track == TRACK_BIT_X) ||
+	(image++,                           track == TRACK_BIT_UPPER) ||
+	(image++,                           track == TRACK_BIT_LOWER) ||
+	(image++,                           track == TRACK_BIT_RIGHT) ||
+	(image++,                           track == TRACK_BIT_LEFT) ||
+	(image++,                           track == TRACK_BIT_CROSS) ||
+
+	(image = rti->base_sprites.track_ns, track == TRACK_BIT_HORZ) ||
+	(image++,                            track == TRACK_BIT_VERT) ||
+
+	(junction = true, false) ||
+	(image = rti->base_sprites.ground, (track & TRACK_BIT_3WAY_NE) == 0) ||
+	(image++,                          (track & TRACK_BIT_3WAY_SW) == 0) ||
+	(image++,                          (track & TRACK_BIT_3WAY_NW) == 0) ||
+	(image++,                          (track & TRACK_BIT_3WAY_SE) == 0) ||
+	(image++, true);
+
+	if (ti->tileh != SLOPE_FLAT) {
+		uint foundation = GetRailFoundation(ti->tileh, track);
+
+		if (foundation != 0) DrawFoundation(ti, foundation);
+
+		// DrawFoundation() modifies ti.
+		// Default sloped sprites..
+		if (ti->tileh != SLOPE_FLAT)
+			image = _track_sloped_sprites[ti->tileh - 1] + rti->base_sprites.track_y;
+	}
+
+	switch (GetRailGroundType(ti->tile)) {
+		case RAIL_GROUND_BARREN:     image |= PALETTE_TO_BARE_LAND; break;
+		case RAIL_GROUND_ICE_DESERT: image += rti->snow_offset; break;
+		default: break;
+	}
+
+	DrawGroundSprite(image);
+
+	// Draw track pieces individually for junction tiles
+	if (junction) {
+		if (track & TRACK_BIT_X)     DrawGroundSprite(rti->base_sprites.single_y);
+		if (track & TRACK_BIT_Y)     DrawGroundSprite(rti->base_sprites.single_x);
+		if (track & TRACK_BIT_UPPER) DrawGroundSprite(rti->base_sprites.single_n);
+		if (track & TRACK_BIT_LOWER) DrawGroundSprite(rti->base_sprites.single_s);
+		if (track & TRACK_BIT_LEFT)  DrawGroundSprite(rti->base_sprites.single_w);
+		if (track & TRACK_BIT_RIGHT) DrawGroundSprite(rti->base_sprites.single_e);
+	}
+
+	if (GetRailType(ti->tile) == RAILTYPE_ELECTRIC) DrawCatenary(ti);
+
+}
+
+static void DrawSignals(TileIndex tile, TrackBits rails)
+{
+#define MAYBE_DRAW_SIGNAL(x,y,z) if (IsSignalPresent(tile, x)) DrawSingleSignal(tile, GetSingleSignalState(tile, x), y - 0x4FB, z)
+
+	if (!(rails & TRACK_BIT_Y)) {
+		if (!(rails & TRACK_BIT_X)) {
+			if (rails & TRACK_BIT_LEFT) {
+				MAYBE_DRAW_SIGNAL(2, 0x509, 0);
+				MAYBE_DRAW_SIGNAL(3, 0x507, 1);
+			}
+			if (rails & TRACK_BIT_RIGHT) {
+				MAYBE_DRAW_SIGNAL(0, 0x509, 2);
+				MAYBE_DRAW_SIGNAL(1, 0x507, 3);
+			}
+			if (rails & TRACK_BIT_UPPER) {
+				MAYBE_DRAW_SIGNAL(3, 0x505, 4);
+				MAYBE_DRAW_SIGNAL(2, 0x503, 5);
+			}
+			if (rails & TRACK_BIT_LOWER) {
+				MAYBE_DRAW_SIGNAL(1, 0x505, 6);
+				MAYBE_DRAW_SIGNAL(0, 0x503, 7);
+			}
+		} else {
+			MAYBE_DRAW_SIGNAL(3, 0x4FB, 8);
+			MAYBE_DRAW_SIGNAL(2, 0x4FD, 9);
+		}
+	} else {
+		MAYBE_DRAW_SIGNAL(3, 0x4FF, 10);
+		MAYBE_DRAW_SIGNAL(2, 0x501, 11);
+	}
+}
+
+static void DrawTile_Track(TileInfo *ti)
+{
+	const RailtypeInfo *rti = GetRailTypeInfo(GetRailType(ti->tile));
+	PalSpriteID image;
+
+	_drawtile_track_palette = SPRITE_PALETTE(PLAYER_SPRITE_COLOR(GetTileOwner(ti->tile)));
+
+	if (IsPlainRailTile(ti->tile)) {
+		TrackBits rails = GetTrackBits(ti->tile);
+
+		DrawTrackBits(ti, rails);
+
+		if (_display_opt & DO_FULL_DETAIL) DrawTrackDetails(ti);
+
+		if (HasSignals(ti->tile)) DrawSignals(ti->tile, rails);
+	} else {
+		// draw depot/waypoint
+		const DrawTileSprites* dts;
+		const DrawTileSeqStruct* dtss;
+		uint32 relocation;
+
+		if (ti->tileh != SLOPE_FLAT) DrawFoundation(ti, ti->tileh);
+
+		if (GetRailTileSubtype(ti->tile) == RAIL_SUBTYPE_DEPOT) {
+			dts = &_depot_gfx_table[GetRailDepotDirection(ti->tile)];
+
+			relocation = rti->total_offset;
+
+			image = dts->ground_sprite;
+			if (image != SPR_FLAT_GRASS_TILE) image += rti->total_offset;
+
+			// adjust ground tile for desert
+			// don't adjust for snow, because snow in depots looks weird
+			if (IsSnowRailGround(ti->tile) && _opt.landscape == LT_DESERT) {
+				if (image != SPR_FLAT_GRASS_TILE) {
+					image += rti->snow_offset; // tile with tracks
+				} else {
+					image = SPR_FLAT_SNOWY_TILE; // flat ground
+				}
+			}
+		} else {
+			// look for customization
+			byte stat_id = GetWaypointByTile(ti->tile)->stat_id;
+			const StationSpec *statspec = GetCustomStationSpec(STAT_CLASS_WAYP, stat_id);
+
+			if (statspec != NULL) {
+				// emulate station tile - open with building
+				const Station* st = ComposeWaypointStation(ti->tile);
+				uint gfx = 2;
+
+				if (HASBIT(statspec->callbackmask, CBM_CUSTOM_LAYOUT)) {
+					uint16 callback = GetStationCallback(CBID_STATION_SPRITE_LAYOUT, 0, 0, statspec, st, ti->tile);
+					if (callback != CALLBACK_FAILED) gfx = callback;
+				}
+
+				if (statspec->renderdata == NULL) {
+					dts = GetStationTileLayout(gfx);
+				} else {
+					dts = &statspec->renderdata[(gfx < statspec->tiles ? gfx : 0) + GetWaypointAxis(ti->tile)];
+				}
+
+				if (dts != NULL && dts->seq != NULL) {
+					relocation = GetCustomStationRelocation(statspec, st, ti->tile);
+
+					image = dts->ground_sprite;
+					if (HASBIT(image, 31)) {
+						CLRBIT(image, 31);
+						image += GetCustomStationGroundRelocation(statspec, st, ti->tile);
+						image += rti->custom_ground_offset;
+					} else {
+						image += rti->total_offset;
+					}
+				} else {
+					goto default_waypoint;
+				}
+			} else {
+default_waypoint:
+				// There is no custom layout, fall back to the default graphics
+				dts = &_waypoint_gfx_table[GetWaypointAxis(ti->tile)];
+				relocation = 0;
+				image = dts->ground_sprite + rti->total_offset;
+				if (IsSnowRailGround(ti->tile)) image += rti->snow_offset;
+			}
+		}
+
+		DrawGroundSprite(image);
+
+		if (GetRailType(ti->tile) == RAILTYPE_ELECTRIC) DrawCatenary(ti);
+
+		foreach_draw_tile_seq(dtss, dts->seq) {
+			uint32 image = dtss->image + relocation;
+
+			if (_display_opt & DO_TRANS_BUILDINGS) {
+				MAKE_TRANSPARENT(image);
+			} else if (image & PALETTE_MODIFIER_COLOR) {
+				image |= _drawtile_track_palette;
+			}
+			AddSortableSpriteToDraw(
+				image,
+				ti->x + dtss->delta_x, ti->y + dtss->delta_y,
+				dtss->size_x, dtss->size_y,
+				dtss->size_z, ti->z + dtss->delta_z
+			);
+		}
+	}
+	DrawBridgeMiddle(ti);
+}
+
+
+static void DrawTileSequence(int x, int y, uint32 ground, const DrawTileSeqStruct* dtss, uint32 offset)
+{
+	uint32 palette = PLAYER_SPRITE_COLOR(_local_player);
+
+	DrawSprite(ground, x, y);
+	for (; dtss->image != 0; dtss++) {
+		Point pt = RemapCoords(dtss->delta_x, dtss->delta_y, dtss->delta_z);
+		uint32 image = dtss->image + offset;
+
+		if (image & PALETTE_MODIFIER_COLOR) image |= palette;
+		DrawSprite(image, x + pt.x, y + pt.y);
+	}
+}
+
+void DrawTrainDepotSprite(int x, int y, int dir, RailType railtype)
+{
+	const DrawTileSprites* dts = &_depot_gfx_table[dir];
+	uint32 image = dts->ground_sprite;
+	uint32 offset = GetRailTypeInfo(railtype)->total_offset;
+
+	if (image != SPR_FLAT_GRASS_TILE) image += offset;
+	DrawTileSequence(x + 33, y + 17, image, dts->seq, offset);
+}
+
+void DrawDefaultWaypointSprite(int x, int y, RailType railtype)
+{
+	uint32 offset = GetRailTypeInfo(railtype)->total_offset;
+	const DrawTileSprites* dts = &_waypoint_gfx_table[AXIS_X];
+
+	DrawTileSequence(x, y, dts->ground_sprite + offset, dts->seq, 0);
+}
+
+typedef struct SetSignalsData {
+	int cur;
+	int cur_stack;
+	bool stop;
+	bool has_presignal;
+
+	// presignal info
+	int presignal_exits;
+	int presignal_exits_free;
+
+	// these are used to keep track of the signals that change.
+	byte bit[NUM_SSD_ENTRY];
+	TileIndex tile[NUM_SSD_ENTRY];
+
+	// these are used to keep track of the stack that modifies presignals recursively
+	TileIndex next_tile[NUM_SSD_STACK];
+	byte next_dir[NUM_SSD_STACK];
+
+} SetSignalsData;
+
+static bool SetSignalsEnumProc(TileIndex tile, void* data, int track, uint length, byte* state)
+{
+	SetSignalsData* ssd = data;
+
+	if (!IsTileType(tile, MP_RAILWAY)) return false;
+
+	// the tile has signals?
+	if (HasSignalOnTrack(tile, TrackdirToTrack(track))) {
+		if (HasSignalOnTrackdir(tile, ReverseTrackdir(track))) {
+			// yes, add the signal to the list of signals
+			if (ssd->cur != NUM_SSD_ENTRY) {
+				ssd->tile[ssd->cur] = tile; // remember the tile index
+				ssd->bit[ssd->cur] = track; // and the controlling bit number
+				ssd->cur++;
+			}
+
+			// remember if this block has a presignal.
+			ssd->has_presignal |= IsPresignalEntry(tile);
+		}
+
+		if (HasSignalOnTrackdir(tile, track) && IsPresignalExit(tile)) {
+			// this is an exit signal that points out from the segment
+			ssd->presignal_exits++;
+			if (GetSignalStateByTrackdir(tile, track) != SIGNAL_STATE_RED)
+				ssd->presignal_exits_free++;
+		}
+
+		return true;
+	} else if (IsTileDepotType(tile, TRANSPORT_RAIL)) {
+		return true; // don't look further if the tile is a depot
+	}
+
+	return false;
+}
+
+/* Struct to parse data from VehicleFromPos to SignalVehicleCheckProc */
+typedef struct SignalVehicleCheckStruct {
+	TileIndex tile;
+	uint track;
+} SignalVehicleCheckStruct;
+
+static void *SignalVehicleCheckProc(Vehicle *v, void *data)
+{
+	const SignalVehicleCheckStruct* dest = data;
+
+	if (v->type != VEH_Train) return NULL;
+
+	/* Wrong tile, or no train? Not a match */
+	if (v->tile != dest->tile) return NULL;
+
+	/* Are we on the same piece of track? */
+	if (dest->track & v->u.rail.track * 0x101) return v;
+
+	return NULL;
+}
+
+/* Special check for SetSignalsAfterProc, to see if there is a vehicle on this tile */
+static bool SignalVehicleCheck(TileIndex tile, uint track)
+{
+	SignalVehicleCheckStruct dest;
+
+	dest.tile = tile;
+	dest.track = track;
+
+	/* Locate vehicles in tunnels or on bridges */
+	if (IsTunnelTile(tile) || IsBridgeTile(tile)) {
+		TileIndex end;
+		DiagDirection direction;
+
+		if (IsTunnelTile(tile)) {
+			end = GetOtherTunnelEnd(tile);
+			direction = GetTunnelDirection(tile);
+		} else {
+			end = GetOtherBridgeEnd(tile);
+			direction = GetBridgeRampDirection(tile);
+		}
+
+		dest.track = 1 << (direction & 1); // get the trackbit the vehicle would have if it has not entered the tunnel yet (ie is still visible)
+
+		// check for a vehicle with that trackdir on the start tile of the tunnel
+		if (VehicleFromPos(tile, &dest, SignalVehicleCheckProc) != NULL) return true;
+
+		// check for a vehicle with that trackdir on the end tile of the tunnel
+		if (VehicleFromPos(end, &dest, SignalVehicleCheckProc) != NULL) return true;
+
+		// now check all tiles from start to end for a warping vehicle
+		// NOTE: the hashes for tiles may overlap, so this could maybe be optimised a bit by not checking every tile?
+		dest.track = 0x40;   //Vehicle inside a tunnel or on a bridge
+		for (; tile != end; tile += TileOffsByDiagDir(direction)) {
+			if (VehicleFromPos(tile, &dest, SignalVehicleCheckProc) != NULL)
+				return true;
+		}
+
+		// no vehicle found
+		return false;
+	}
+
+	return VehicleFromPos(tile, &dest, SignalVehicleCheckProc) != NULL;
+}
+
+static void SetSignalsAfterProc(TrackPathFinder *tpf)
+{
+	SetSignalsData *ssd = tpf->userdata;
+	const TrackPathFinderLink* link;
+	uint offs;
+	uint i;
+
+	ssd->stop = false;
+
+	/* Go through all the PF tiles */
+	for (i = 0; i < lengthof(tpf->hash_head); i++) {
+		/* Empty hash item */
+		if (tpf->hash_head[i] == 0) continue;
+
+		/* If 0x8000 is not set, there is only 1 item */
+		if (!(tpf->hash_head[i] & 0x8000)) {
+			/* Check if there is a vehicle on this tile */
+			if (SignalVehicleCheck(tpf->hash_tile[i], tpf->hash_head[i])) {
+				ssd->stop = true;
+				return;
+			}
+		} else {
+			/* There are multiple items, where hash_tile points to the first item in the list */
+			offs = tpf->hash_tile[i];
+			do {
+				/* Find the next item */
+				link = PATHFIND_GET_LINK_PTR(tpf, offs);
+				/* Check if there is a vehicle on this tile */
+				if (SignalVehicleCheck(link->tile, link->flags)) {
+					ssd->stop = true;
+					return;
+				}
+				/* Goto the next item */
+			} while ((offs = link->next) != 0xFFFF);
+		}
+	}
+}
+
+static const byte _dir_from_track[14] = {
+	0,1,0,1,2,1, 0,0,
+	2,3,3,2,3,0,
+};
+
+
+static void ChangeSignalStates(SetSignalsData *ssd)
+{
+	int i;
+
+	// thinking about presignals...
+	// the presignal is green if,
+	//   if no train is in the segment AND
+	//   there is at least one green exit signal OR
+	//   there are no exit signals in the segment
+
+	// then mark the signals in the segment accordingly
+	for (i = 0; i != ssd->cur; i++) {
+		TileIndex tile = ssd->tile[i];
+		byte bit = SignalAgainstTrackdir(ssd->bit[i]);
+		uint16 m2 = _m[tile].m2;
+
+		// presignals don't turn green if there is at least one presignal exit and none are free
+		if (IsPresignalEntry(tile)) {
+			int ex = ssd->presignal_exits, exfree = ssd->presignal_exits_free;
+
+			// subtract for dual combo signals so they don't count themselves
+			if (IsPresignalExit(tile) && HasSignalOnTrackdir(tile, ssd->bit[i])) {
+				ex--;
+				if (GetSignalStateByTrackdir(tile, ssd->bit[i]) != SIGNAL_STATE_RED) exfree--;
+			}
+
+			// if we have exits and none are free, make red.
+			if (ex && !exfree) goto make_red;
+		}
+
+		// check if the signal is unaffected.
+		if (ssd->stop) {
+make_red:
+			// turn red
+			if ((bit & m2) == 0) continue;
+		} else {
+			// turn green
+			if ((bit & m2) != 0) continue;
+		}
+
+		/* Update signals on the other side of this exit-combo signal; it changed. */
+		if (IsPresignalExit(tile)) {
+			if (ssd->cur_stack != NUM_SSD_STACK) {
+				ssd->next_tile[ssd->cur_stack] = tile;
+				ssd->next_dir[ssd->cur_stack] = _dir_from_track[ssd->bit[i]];
+				ssd->cur_stack++;
+			} else {
+				DEBUG(misc, 0, "NUM_SSD_STACK too small"); /// @todo WTF is this???
+			}
+		}
+
+		// it changed, so toggle it
+		_m[tile].m2 = m2 ^ bit;
+		MarkTileDirtyByTile(tile);
+	}
+}
+
+
+bool UpdateSignalsOnSegment(TileIndex tile, DiagDirection direction)
+{
+	SetSignalsData ssd;
+	int result = -1;
+
+	ssd.cur_stack = 0;
+
+	for (;;) {
+		// go through one segment and update all signals pointing into that segment.
+		ssd.cur = ssd.presignal_exits = ssd.presignal_exits_free = 0;
+		ssd.has_presignal = false;
+
+		FollowTrack(tile, 0xC000 | TRANSPORT_RAIL, direction, SetSignalsEnumProc, SetSignalsAfterProc, &ssd);
+		ChangeSignalStates(&ssd);
+
+		// remember the result only for the first iteration.
+		if (result < 0) {
+			// stay in depot while segment is occupied or while all presignal exits are blocked
+			result = ssd.stop || (ssd.presignal_exits > 0 && ssd.presignal_exits_free == 0);
+		}
+
+		// if any exit signals were changed, we need to keep going to modify the stuff behind those.
+		if (ssd.cur_stack == 0) break;
+
+		// one or more exit signals were changed, so we need to update another segment too.
+		tile = ssd.next_tile[--ssd.cur_stack];
+		direction = ssd.next_dir[ssd.cur_stack];
+	}
+
+	return result != 0;
+}
+
+void SetSignalsOnBothDir(TileIndex tile, byte track)
+{
+	static const DiagDirection _search_dir_1[] = {
+		DIAGDIR_NE, DIAGDIR_SE, DIAGDIR_NE, DIAGDIR_SE, DIAGDIR_SW, DIAGDIR_SE
+	};
+	static const DiagDirection _search_dir_2[] = {
+		DIAGDIR_SW, DIAGDIR_NW, DIAGDIR_NW, DIAGDIR_SW, DIAGDIR_NW, DIAGDIR_NE
+	};
+
+	UpdateSignalsOnSegment(tile, _search_dir_1[track]);
+	UpdateSignalsOnSegment(tile, _search_dir_2[track]);
+}
+
+static uint GetSlopeZ_Track(TileIndex tile, uint x, uint y)
+{
+	uint z;
+	Slope tileh = GetTileSlope(tile, &z);
+
+	if (tileh == SLOPE_FLAT) return z;
+	if (IsPlainRailTile(tile)) {
+		uint f = GetRailFoundation(tileh, GetTrackBits(tile));
+
+		if (f != 0) {
+			if (IsSteepSlope(tileh)) {
+				z += TILE_HEIGHT;
+			} else if (f < 15) {
+				return z + TILE_HEIGHT; // leveled foundation
+			}
+			tileh = _inclined_tileh[f - 15]; // inclined foundation
+		}
+		return z + GetPartialZ(x & 0xF, y & 0xF, tileh);
+	} else {
+		return z + TILE_HEIGHT;
+	}
+}
+
+static Slope GetSlopeTileh_Track(TileIndex tile, Slope tileh)
+{
+	if (tileh == SLOPE_FLAT) return SLOPE_FLAT;
+	if (IsPlainRailTile(tile)) {
+		uint f = GetRailFoundation(tileh, GetTrackBits(tile));
+
+		if (f == 0) return tileh;
+		if (f < 15) return SLOPE_FLAT; // leveled foundation
+		return _inclined_tileh[f - 15]; // inclined foundation
+	} else {
+		return SLOPE_FLAT;
+	}
+}
+
+static void GetAcceptedCargo_Track(TileIndex tile, AcceptedCargo ac)
+{
+	/* not used */
+}
+
+static void AnimateTile_Track(TileIndex tile)
+{
+	/* not used */
+}
+
+static void TileLoop_Track(TileIndex tile)
+{
+	RailGroundType old_ground = GetRailGroundType(tile);
+	RailGroundType new_ground;
+
+	switch (_opt.landscape) {
+		case LT_HILLY:
+			if (GetTileZ(tile) > _opt.snow_line) {
+				new_ground = RAIL_GROUND_ICE_DESERT;
+				goto set_ground;
+			}
+			break;
+
+		case LT_DESERT:
+			if (GetTropicZone(tile) == TROPICZONE_DESERT) {
+				new_ground = RAIL_GROUND_ICE_DESERT;
+				goto set_ground;
+			}
+			break;
+	}
+
+	if (!IsPlainRailTile(tile)) return;
+
+	new_ground = RAIL_GROUND_GRASS;
+
+	if (old_ground != RAIL_GROUND_BARREN) { /* wait until bottom is green */
+		/* determine direction of fence */
+		TrackBits rail = GetTrackBits(tile);
+
+		switch (rail) {
+			case TRACK_BIT_UPPER: new_ground = RAIL_GROUND_FENCE_HORIZ1; break;
+			case TRACK_BIT_LOWER: new_ground = RAIL_GROUND_FENCE_HORIZ2; break;
+			case TRACK_BIT_LEFT:  new_ground = RAIL_GROUND_FENCE_VERT1;  break;
+			case TRACK_BIT_RIGHT: new_ground = RAIL_GROUND_FENCE_VERT2;  break;
+
+			default: {
+				PlayerID owner = GetTileOwner(tile);
+
+				if (rail == (TRACK_BIT_LOWER | TRACK_BIT_RIGHT) || (
+							(rail & TRACK_BIT_3WAY_NW) == 0 &&
+							(rail & TRACK_BIT_X)
+						)) {
+					TileIndex n = tile + TileDiffXY(0, -1);
+					TrackBits nrail = GetTrackBits(n);
+
+					if (!IsTileType(n, MP_RAILWAY) ||
+							!IsTileOwner(n, owner) ||
+							nrail == TRACK_BIT_UPPER ||
+							nrail == TRACK_BIT_LEFT) {
+						new_ground = RAIL_GROUND_FENCE_NW;
+					}
+				}
+
+				if (rail == (TRACK_BIT_UPPER | TRACK_BIT_LEFT) || (
+							(rail & TRACK_BIT_3WAY_SE) == 0 &&
+							(rail & TRACK_BIT_X)
+						)) {
+					TileIndex n = tile + TileDiffXY(0, 1);
+					TrackBits nrail = GetTrackBits(n);
+
+					if (!IsTileType(n, MP_RAILWAY) ||
+							!IsTileOwner(n, owner) ||
+							nrail == TRACK_BIT_LOWER ||
+							nrail == TRACK_BIT_RIGHT) {
+						new_ground = (new_ground == RAIL_GROUND_FENCE_NW) ?
+							RAIL_GROUND_FENCE_SENW : RAIL_GROUND_FENCE_SE;
+					}
+				}
+
+				if (rail == (TRACK_BIT_LOWER | TRACK_BIT_LEFT) || (
+							(rail & TRACK_BIT_3WAY_NE) == 0 &&
+							(rail & TRACK_BIT_Y)
+						)) {
+					TileIndex n = tile + TileDiffXY(-1, 0);
+					TrackBits nrail = GetTrackBits(n);
+
+					if (!IsTileType(n, MP_RAILWAY) ||
+							!IsTileOwner(n, owner) ||
+							nrail == TRACK_BIT_UPPER ||
+							nrail == TRACK_BIT_RIGHT) {
+						new_ground = RAIL_GROUND_FENCE_NE;
+					}
+				}
+
+				if (rail == (TRACK_BIT_UPPER | TRACK_BIT_RIGHT) || (
+							(rail & TRACK_BIT_3WAY_SW) == 0 &&
+							(rail & TRACK_BIT_Y)
+						)) {
+					TileIndex n = tile + TileDiffXY(1, 0);
+					TrackBits nrail = GetTrackBits(n);
+
+					if (!IsTileType(n, MP_RAILWAY) ||
+							!IsTileOwner(n, owner) ||
+							nrail == TRACK_BIT_LOWER ||
+							nrail == TRACK_BIT_LEFT) {
+						new_ground = (new_ground == RAIL_GROUND_FENCE_NE) ?
+							RAIL_GROUND_FENCE_NESW : RAIL_GROUND_FENCE_SW;
+					}
+				}
+				break;
+			}
+		}
+	}
+
+set_ground:
+	if (old_ground != new_ground) {
+		SetRailGroundType(tile, new_ground);
+		MarkTileDirtyByTile(tile);
+	}
+}
+
+
+static uint32 GetTileTrackStatus_Track(TileIndex tile, TransportType mode)
+{
+	byte a;
+	uint16 b;
+
+	if (mode != TRANSPORT_RAIL) return 0;
+
+	if (IsPlainRailTile(tile)) {
+		TrackBits rails = GetTrackBits(tile);
+		uint32 ret = rails * 0x101;
+
+		if (HasSignals(tile)) {
+			a = _m[tile].m3;
+			b = _m[tile].m2;
+
+			b &= a;
+
+			/* When signals are not present (in neither
+			 * direction), we pretend them to be green. (So if
+			 * signals are only one way, the other way will
+			 * implicitely become `red' */
+			if ((a & 0xC0) == 0) b |= 0xC0;
+			if ((a & 0x30) == 0) b |= 0x30;
+
+			if ((b & 0x80) == 0) ret |= 0x10070000;
+			if ((b & 0x40) == 0) ret |= 0x07100000;
+			if ((b & 0x20) == 0) ret |= 0x20080000;
+			if ((b & 0x10) == 0) ret |= 0x08200000;
+		} else {
+			if (rails == TRACK_BIT_CROSS) ret |= 0x40;
+		}
+		return ret;
+	} else {
+		if (GetRailTileSubtype(tile) == RAIL_SUBTYPE_DEPOT) {
+			return AxisToTrackBits(DiagDirToAxis(GetRailDepotDirection(tile))) * 0x101;
+		} else {
+			return GetRailWaypointBits(tile) * 0x101;
+		}
+	}
+}
+
+static void ClickTile_Track(TileIndex tile)
+{
+	if (IsTileDepotType(tile, TRANSPORT_RAIL)) {
+		ShowDepotWindow(tile, VEH_Train);
+	} else if (IsRailWaypoint(tile)) {
+		ShowRenameWaypointWindow(GetWaypointByTile(tile));
+	}
+}
+
+static void GetTileDesc_Track(TileIndex tile, TileDesc *td)
+{
+	td->owner = GetTileOwner(tile);
+	switch (GetRailTileType(tile)) {
+		case RAIL_TILE_NORMAL:
+			td->str = STR_1021_RAILROAD_TRACK;
+			break;
+
+		case RAIL_TILE_SIGNALS: {
+			const StringID signal_type[] = {
+				STR_RAILROAD_TRACK_WITH_NORMAL_SIGNALS,
+				STR_RAILROAD_TRACK_WITH_PRESIGNALS,
+				STR_RAILROAD_TRACK_WITH_EXITSIGNALS,
+				STR_RAILROAD_TRACK_WITH_COMBOSIGNALS
+			};
+
+			td->str = signal_type[GetSignalType(tile)];
+			break;
+		}
+
+		case RAIL_TILE_DEPOT_WAYPOINT:
+		default:
+			td->str = (GetRailTileSubtype(tile) == RAIL_SUBTYPE_DEPOT) ?
+				STR_1023_RAILROAD_TRAIN_DEPOT : STR_LANDINFO_WAYPOINT;
+			break;
+	}
+}
+
+static void ChangeTileOwner_Track(TileIndex tile, PlayerID old_player, PlayerID new_player)
+{
+	if (!IsTileOwner(tile, old_player)) return;
+
+	if (new_player != PLAYER_SPECTATOR) {
+		SetTileOwner(tile, new_player);
+	} else {
+		DoCommand(tile, 0, 0, DC_EXEC, CMD_LANDSCAPE_CLEAR);
+	}
+}
+
+static const byte _fractcoords_behind[4] = { 0x8F, 0x8, 0x80, 0xF8 };
+static const byte _fractcoords_enter[4] = { 0x8A, 0x48, 0x84, 0xA8 };
+static const byte _deltacoord_leaveoffset[8] = {
+	-1,  0,  1,  0, /* x */
+	 0,  1,  0, -1  /* y */
+};
+
+static uint32 VehicleEnter_Track(Vehicle *v, TileIndex tile, int x, int y)
+{
+	byte fract_coord;
+	byte fract_coord_leave;
+	DiagDirection dir;
+	int length;
+
+	// this routine applies only to trains in depot tiles
+	if (v->type != VEH_Train || !IsTileDepotType(tile, TRANSPORT_RAIL)) return 0;
+
+	/* depot direction */
+	dir = GetRailDepotDirection(tile);
+
+	/* calculate the point where the following wagon should be activated */
+	/* this depends on the length of the current vehicle */
+	length = v->u.rail.cached_veh_length;
+
+	fract_coord_leave =
+		((_fractcoords_enter[dir] & 0x0F) + // x
+			(length + 1) * _deltacoord_leaveoffset[dir]) +
+		(((_fractcoords_enter[dir] >> 4) +  // y
+			((length + 1) * _deltacoord_leaveoffset[dir+4])) << 4);
+
+	fract_coord = (x & 0xF) + ((y & 0xF) << 4);
+
+	if (_fractcoords_behind[dir] == fract_coord) {
+		/* make sure a train is not entering the tile from behind */
+		return 8;
+	} else if (_fractcoords_enter[dir] == fract_coord) {
+		if (DiagDirToDir(ReverseDiagDir(dir)) == v->direction) {
+			/* enter the depot */
+			v->u.rail.track = 0x80,
+			v->vehstatus |= VS_HIDDEN; /* hide it */
+			v->direction = ReverseDir(v->direction);
+			if (v->next == NULL) VehicleEnterDepot(v);
+			v->tile = tile;
+
+			InvalidateWindowData(WC_VEHICLE_DEPOT, v->tile);
+			return 4;
+		}
+	} else if (fract_coord_leave == fract_coord) {
+		if (DiagDirToDir(dir) == v->direction) {
+			/* leave the depot? */
+			if ((v = v->next) != NULL) {
+				v->vehstatus &= ~VS_HIDDEN;
+				v->u.rail.track = (DiagDirToAxis(dir) == AXIS_X ? 1 : 2);
+			}
+		}
+	}
+
+	return 0;
+}
+
+
+const TileTypeProcs _tile_type_rail_procs = {
+	DrawTile_Track,           /* draw_tile_proc */
+	GetSlopeZ_Track,          /* get_slope_z_proc */
+	ClearTile_Track,          /* clear_tile_proc */
+	GetAcceptedCargo_Track,   /* get_accepted_cargo_proc */
+	GetTileDesc_Track,        /* get_tile_desc_proc */
+	GetTileTrackStatus_Track, /* get_tile_track_status_proc */
+	ClickTile_Track,          /* click_tile_proc */
+	AnimateTile_Track,        /* animate_tile_proc */
+	TileLoop_Track,           /* tile_loop_clear */
+	ChangeTileOwner_Track,    /* change_tile_owner_clear */
+	NULL,                     /* get_produced_cargo_proc */
+	VehicleEnter_Track,       /* vehicle_enter_tile_proc */
+	GetSlopeTileh_Track,      /* get_slope_tileh_proc */
+};