--- a/src/airport.h
+++ b/src/airport.h
@@ -6,6 +6,7 @@
 #define AIRPORT_H
 
 #include "direction_type.h"
+#include "map.h"
 
 enum {MAX_TERMINALS =  10};
 enum {MAX_HELIPADS  =   4};

--- a/src/aystar.h
+++ b/src/aystar.h
@@ -12,6 +12,7 @@
 #define AYSTAR_H
 
 #include "queue.h"
+#include "tile_type.h"
 
 //#define AYSTAR_DEBUG
 enum {

--- a/src/bridge.h
+++ b/src/bridge.h
@@ -6,6 +6,7 @@
 #define BRIDGE_H
 
 #include "gfx_type.h"
+#include "tile_cmd.h"
 
 enum {
 	MAX_BRIDGES = 13

--- a/src/clear_cmd.cpp
+++ b/src/clear_cmd.cpp
@@ -24,6 +24,7 @@
 #include "tile_cmd.h"
 #include "vehicle.h"
 #include "functions.h"
+#include "economy_func.h"
 
 /*
  * In one terraforming command all four corners of a initial tile can be raised/lowered (though this is not available to the player).

--- a/src/economy_func.h
+++ b/src/economy_func.h
@@ -9,6 +9,7 @@
 #include "economy_type.h"
 #include "cargo_type.h"
 #include "vehicle_type.h"
+#include "tile_type.h"
 
 struct Player;
 

--- a/src/functions.h
+++ b/src/functions.h
@@ -8,6 +8,8 @@
 #include "core/random_func.hpp"
 #include "command_type.h"
 #include "openttd.h"
+#include "tile_cmd.h"
+#include "map.h"
 
 /* clear_land.cpp */
 void DrawHillyLandTile(const TileInfo *ti);

--- a/src/genworld.cpp
+++ b/src/genworld.cpp
@@ -19,6 +19,7 @@
 #include "heightmap.h"
 #include "date.h"
 #include "viewport.h"
+#include "map.h"
 
 void GenerateClearTile();
 void GenerateIndustries();

--- a/src/gui.h
+++ b/src/gui.h
@@ -9,6 +9,7 @@
 #include "vehicle_type.h"
 #include "gfx_type.h"
 #include "economy_type.h"
+#include "tile_type.h"
 
 /* main_gui.cpp */
 void CcPlaySound10(bool success, TileIndex tile, uint32 p1, uint32 p2);
@@ -52,10 +53,12 @@
 void ShowGenerateLandscape();
 void ShowHeightmapLoad();
 
+typedef void PlaceProc(TileIndex tile);
 void PlaceProc_DemolishArea(TileIndex tile);
 void PlaceProc_LevelLand(TileIndex tile);
 void PlaceProc_BuyLand(TileIndex tile);
 bool GUIPlaceProcDragXY(const WindowEvent *e);
+VARDEF PlaceProc *_place_proc;
 
 /** Drag and drop selection process, or, what to do with an area of land when
  * you've selected it. */
@@ -121,7 +124,6 @@
 /* main_gui.cpp */
 void HandleOnEditText(const char *str);
 VARDEF bool _station_show_coverage;
-VARDEF PlaceProc *_place_proc;
 
 void InitializeGUI();
 

--- a/src/industry.h
+++ b/src/industry.h
@@ -10,6 +10,8 @@
 #include "newgrf_storage.h"
 #include "cargo_type.h"
 #include "economy_type.h"
+#include "map.h"
+#include "slope_type.h"
 
 typedef uint16 IndustryGfx;
 typedef uint8 IndustryType;

--- a/src/landscape.h
+++ b/src/landscape.h
@@ -6,6 +6,9 @@
 #define LANDSCAPE_H
 
 #include "core/geometry_type.hpp"
+#include "tile_cmd.h"
+#include "slope_type.h"
+#include "direction_type.h"
 
 enum {
 	SNOW_LINE_MONTHS = 12,

--- a/src/map.h
+++ b/src/map.h
@@ -186,17 +186,6 @@
 }
 
 
-enum {
-	INVALID_TILE = (TileIndex)-1 ///< The very nice invalid tile marker
-};
-
-enum {
-	TILE_SIZE   = 16,   ///< Tiles are 16x16 "units" in size
-	TILE_PIXELS = 32,   ///< a tile is 32x32 pixels
-	TILE_HEIGHT =  8,   ///< The standard height-difference between tiles on two levels is 8 (z-diff 8)
-};
-
-
 /**
  * Get the X component of a tile
  * @param tile the tile to get the X component of

--- a/src/news.h
+++ b/src/news.h
@@ -7,6 +7,7 @@
 
 #include "window_type.h"
 #include "vehicle_type.h"
+#include "tile_type.h"
 
 struct NewsItem {
 	StringID string_id; ///< Message text (sometimes also used for storing other info)

--- a/src/openttd.h
+++ b/src/openttd.h
@@ -8,11 +8,9 @@
 #define VARDEF extern
 #endif
 
+#include "core/enum_type.hpp"
 #include "strings_type.h"
 
-#include "map.h"
-#include "slope_type.h"
-
 // Forward declarations of structs.
 struct Depot;
 struct Waypoint;
@@ -144,15 +142,6 @@
 typedef TinyEnumT<TransportType> TransportTypeByte;
 
 
-struct TileInfo {
-	uint x;
-	uint y;
-	Slope tileh;
-	TileIndex tile;
-	uint z;
-};
-
-
 /* Display Options */
 enum {
 	DO_SHOW_TOWN_NAMES    = 0,
@@ -216,21 +205,12 @@
 	GDType town_council_tolerance; // minimum required town ratings to be allowed to demolish stuff
 };
 
-struct TileDesc {
-	StringID str;
-	Owner owner;
-	Date build_date;
-	uint64 dparam[2];
-};
-
 struct ViewportSign {
 	int32 left;
 	int32 top;
 	byte width_1, width_2;
 };
 
-typedef void PlaceProc(TileIndex tile);
-
 enum {
 	SORT_ASCENDING  = 0,
 	SORT_DESCENDING = 1,

--- a/src/order.h
+++ b/src/order.h
@@ -9,6 +9,7 @@
 #include "core/bitmath_func.hpp"
 #include "cargo_type.h"
 #include "vehicle_type.h"
+#include "tile_type.h"
 
 enum {
 	INVALID_VEH_ORDER_ID = 0xFF,

--- a/src/rail.h
+++ b/src/rail.h
@@ -12,6 +12,7 @@
 #include "core/bitmath_func.hpp"
 #include "economy_func.h"
 #include "variables.h"
+#include "tile_cmd.h"
 
 /** This struct contains all the info that is needed to draw and construct tracks.
  */
@@ -97,42 +98,6 @@
 	NUM_SSD_STACK =  32, ///< max amount of blocks to check recursively
 };
 
-/*
- * Functions to map tracks to the corresponding bits in the signal
- * presence/status bytes in the map. You should not use these directly, but
- * wrapper functions below instead. XXX: Which are these?
- */
-
-/**
- * Maps a trackdir to the bit that stores its status in the map arrays, in the
- * direction along with the trackdir.
- */
-static inline byte SignalAlongTrackdir(Trackdir trackdir)
-{
-	extern const byte _signal_along_trackdir[TRACKDIR_END];
-	return _signal_along_trackdir[trackdir];
-}
-
-/**
- * Maps a trackdir to the bit that stores its status in the map arrays, in the
- * direction against the trackdir.
- */
-static inline byte SignalAgainstTrackdir(Trackdir trackdir)
-{
-	extern const byte _signal_against_trackdir[TRACKDIR_END];
-	return _signal_against_trackdir[trackdir];
-}
-
-/**
- * Maps a Track to the bits that store the status of the two signals that can
- * be present on the given track.
- */
-static inline byte SignalOnTrack(Track track)
-{
-	extern const byte _signal_on_track[TRACK_END];
-	return _signal_on_track[track];
-}
-
 
 
 /**

--- a/src/rail_map.h
+++ b/src/rail_map.h
@@ -5,9 +5,10 @@
 #ifndef RAIL_MAP_H
 #define RAIL_MAP_H
 
+#include "rail_type.h"
+#include "signal_func.h"
 #include "direction_func.h"
 #include "track_func.h"
-#include "rail.h"
 #include "tile_map.h"
 
 

--- a/src/road_func.h
+++ b/src/road_func.h
@@ -7,6 +7,7 @@
 
 #include "core/bitmath_func.hpp"
 #include "road_type.h"
+#include "direction_func.h"
 
 /**
  * Whether the given roadtype is valid.

--- a/src/road_internal.h
+++ b/src/road_internal.h
@@ -5,6 +5,8 @@
 #ifndef ROAD_INTERNAL_H
 #define ROAD_INTERNAL_H
 
+#include "tile_cmd.h"
+
 /**
  * Clean up unneccesary RoadBits of a planed tile.
  * @param tile current tile

--- a/src/screenshot.cpp
+++ b/src/screenshot.cpp
@@ -17,6 +17,7 @@
 #include "zoom_func.h"
 #include "core/alloc_func.hpp"
 #include "core/endian_func.hpp"
+#include "map.h"
 
 char _screenshot_format_name[8];
 uint _num_screenshot_formats;

new file mode 100644
--- /dev/null
+++ b/src/signal_func.h
@@ -0,0 +1,40 @@
+/* $Id$ */
+
+/** @file signal_func.h Functions related to signals. */
+
+#ifndef SIGNAL_FUNC_H
+#define SIGNAL_FUNC_H
+
+#include "track_type.h"
+
+/**
+ * Maps a trackdir to the bit that stores its status in the map arrays, in the
+ * direction along with the trackdir.
+ */
+static inline byte SignalAlongTrackdir(Trackdir trackdir)
+{
+	extern const byte _signal_along_trackdir[TRACKDIR_END];
+	return _signal_along_trackdir[trackdir];
+}
+
+/**
+ * Maps a trackdir to the bit that stores its status in the map arrays, in the
+ * direction against the trackdir.
+ */
+static inline byte SignalAgainstTrackdir(Trackdir trackdir)
+{
+	extern const byte _signal_against_trackdir[TRACKDIR_END];
+	return _signal_against_trackdir[trackdir];
+}
+
+/**
+ * Maps a Track to the bits that store the status of the two signals that can
+ * be present on the given track.
+ */
+static inline byte SignalOnTrack(Track track)
+{
+	extern const byte _signal_on_track[TRACK_END];
+	return _signal_on_track[track];
+}
+
+#endif /* SIGNAL_FUNC_H */

--- a/src/slope_func.h
+++ b/src/slope_func.h
@@ -8,6 +8,7 @@
 #include "core/math_func.hpp"
 #include "slope_type.h"
 #include "direction_type.h"
+#include "tile_type.h"
 
 /**
  * Rangecheck for Corner enumeration.

--- a/src/sound.h
+++ b/src/sound.h
@@ -7,6 +7,7 @@
 
 #include "core/enum_type.hpp"
 #include "vehicle_type.h"
+#include "tile_type.h"
 
 struct MusicFileSettings {
 	byte playlist;

--- a/src/station_map.h
+++ b/src/station_map.h
@@ -8,6 +8,7 @@
 #include "rail_map.h"
 #include "road_map.h"
 #include "station.h"
+#include "rail.h"
 
 typedef byte StationGfx;
 

--- a/src/tile_cmd.h
+++ b/src/tile_cmd.h
@@ -6,9 +6,11 @@
 #define TILE_CMD_H
 
 #include "slope_type.h"
+#include "tile_type.h"
 #include "command_type.h"
 #include "vehicle_type.h"
 #include "cargo_type.h"
+#include "strings_type.h"
 
 /** The returned bits of VehicleEnterTile. */
 enum VehicleEnterTileStatus {
@@ -31,6 +33,21 @@
 };
 DECLARE_ENUM_AS_BIT_SET(VehicleEnterTileStatus);
 
+struct TileInfo {
+	uint x;
+	uint y;
+	Slope tileh;
+	TileIndex tile;
+	uint z;
+};
+
+struct TileDesc {
+	StringID str;
+	Owner owner;
+	Date build_date;
+	uint64 dparam[2];
+};
+
 typedef void DrawTileProc(TileInfo *ti);
 typedef uint GetSlopeZProc(TileIndex tile, uint x, uint y);
 typedef CommandCost ClearTileProc(TileIndex tile, byte flags);

--- a/src/tile_type.h
+++ b/src/tile_type.h
@@ -7,11 +7,15 @@
 
 #include "core/enum_type.hpp"
 
-/** Maximum allowed tile height */
-#define MAX_TILE_HEIGHT 15
+enum {
+	TILE_SIZE   = 16,   ///< Tiles are 16x16 "units" in size
+	TILE_PIXELS = 32,   ///< a tile is 32x32 pixels
+	TILE_HEIGHT =  8,   ///< The standard height-difference between tiles on two levels is 8 (z-diff 8)
 
-/** Maximum allowed snowline height */
-#define MAX_SNOWLINE_HEIGHT (MAX_TILE_HEIGHT - 2)
+	MAX_TILE_HEIGHT     = 15,                    ///< Maximum allowed tile height
+	MAX_SNOWLINE_HEIGHT = (MAX_TILE_HEIGHT - 2), ///< Maximum allowed snowline height
+};
+
 
 /**
  * The different type of a tile.
@@ -51,4 +55,9 @@
  */
 typedef uint32 TileIndex;
 
+/**
+ * The very nice invalid tile marker
+ */
+static const TileIndex INVALID_TILE = (TileIndex)-1;
+
 #endif /* TILE_TYPE_H */

--- a/src/town.h
+++ b/src/town.h
@@ -8,6 +8,7 @@
 #include "oldpool.h"
 #include "core/random_func.hpp"
 #include "cargo_type.h"
+#include "tile_type.h"
 
 enum {
 	HOUSE_NO_CLASS   = 0,

--- a/src/variables.h
+++ b/src/variables.h
@@ -7,6 +7,8 @@
 
 #include "yapf/yapf_settings.h"
 #include "openttd.h"
+#include "tile_type.h"
+#include "strings_type.h"
 
 /* ********* START OF SAVE REGION */
 

--- a/src/vehicle.h
+++ b/src/vehicle.h
@@ -10,6 +10,7 @@
 #include "rail_type.h"
 #include "road_type.h"
 #include "cargo_type.h"
+#include "direction_type.h"
 #include "window_type.h"
 #include "gfx_type.h"
 #include "command_type.h"

--- a/src/viewport.h
+++ b/src/viewport.h
@@ -9,6 +9,7 @@
 #include "window_type.h"
 #include "vehicle_type.h"
 #include "gfx_func.h"
+#include "gui.h"
 
 struct ViewPort {
 	int left,top;                       // screen coordinates for the viewport

--- a/src/waypoint.cpp
+++ b/src/waypoint.cpp
@@ -10,6 +10,7 @@
 #include "map.h"
 #include "order.h"
 #include "rail_map.h"
+#include "rail.h"
 #include "bridge_map.h"
 #include "saveload.h"
 #include "station.h"
@@ -27,6 +28,7 @@
 #include "viewport.h"
 #include "functions.h"
 #include "window_func.h"
+#include "economy_func.h"
 
 enum {
 	MAX_WAYPOINTS_PER_TOWN = 64,