Index: docs/landscape.html
===================================================================
--- docs/landscape.html	(revision 17607)
+++ docs/landscape.html	(working copy)
@@ -450,7 +450,12 @@
          </table>
        </li>
        <li>m2 bit 11: opposite track is reserved, too</li>
-      </ul>
+       <li>m2 bit 15 set = with extended signals
+         <ul>
+           <li>m7 bits 7..0 and m6 bits 2..6 and m2 bits 12..14:  the 15-bit SignalExID </li>
+         </ul>
+       </li>
+       </ul>
      </li>
      <li>m5 bit 7 set, bit 6 set: railway depot
       <ul>
Index: docs/landscape_grid.html
===================================================================
--- docs/landscape_grid.html	(revision 17607)
+++ docs/landscape_grid.html	(working copy)
@@ -101,12 +101,12 @@
       <td class="caption">rail with signals</td>
       <td class="bits">-inherit-</td>
       <td class="bits">-inherit-</td>
-      <td class="bits"><span class="free">OOOO</span> XXXX XXXX XXXX</td>
+      <td class="bits"><span class="used">X</span><span class="abuse">XXX</span> XXXX XXXX XXXX</td>
       <td class="bits">XXXX <span class="option">~~</span>XX</td>
       <td class="bits">XXXX XXXX</td>
       <td class="bits">-inherit-</td>
-      <td class="bits">XX<span class="free">OO OO</span>XX</td>
-      <td class="bits"><span class="free">OOOO OOOO</span></td>
+      <td class="bits">XX<span class="abuse">XX XX</span>XX</td>
+      <td class="bits"><span class="abuse">XXXX XXXX</span></td>
     </tr>
     <tr>
       <td class="caption">depot</td>
Index: source.list
===================================================================
--- source.list	(revision 17607)
+++ source.list	(working copy)
@@ -61,6 +61,7 @@
 #end
 settings.cpp
 signal.cpp
+signalex.cpp
 signs.cpp
 sound.cpp
 spritecache.cpp
@@ -250,6 +251,9 @@
 ship.h
 signal_func.h
 signal_type.h
+signalex_base.h
+signalex_map.h
+signalex_type.h
 signs_base.h
 signs_func.h
 signs_type.h
@@ -464,6 +468,7 @@
 saveload/saveload.cpp
 saveload/saveload.h
 saveload/saveload_internal.h
+saveload/signalex_sl.cpp
 saveload/signs_sl.cpp
 saveload/station_sl.cpp
 saveload/strings_sl.cpp
Index: src/misc.cpp
===================================================================
--- src/misc.cpp	(revision 17607)
+++ src/misc.cpp	(working copy)
@@ -59,6 +59,7 @@
 void InitializeCheats();
 void InitializeNPF();
 void InitializeOldNames();
+void InitializeSignalEx();
 
 void InitializeGame(uint size_x, uint size_y, bool reset_date, bool reset_settings)
 {
@@ -108,6 +109,7 @@
 	InitializeCargoPackets();
 	InitializeIndustries();
 	InitializeBuildingCounts();
+	InitializeSignalEx();
 
 	InitializeNPF();
 
Index: src/openttd.cpp
===================================================================
--- src/openttd.cpp	(revision 17607)
+++ src/openttd.cpp	(working copy)
@@ -63,6 +63,7 @@
 #include "thread/thread.h"
 #include "station_base.h"
 #include "crashlog.h"
+#include "signalex_base.h"
 
 #include "newgrf_commons.h"
 
@@ -345,6 +346,7 @@
 	_cargopacket_pool.CleanPool();
 	_engine_pool.CleanPool();
 	_company_pool.CleanPool();
+	_signalex_pool.CleanPool();
 
 	free(_config_file);
 
Index: src/rail_cmd.cpp
===================================================================
--- src/rail_cmd.cpp	(revision 17607)
+++ src/rail_cmd.cpp	(working copy)
@@ -35,6 +35,7 @@
 #include "functions.h"
 #include "elrail_func.h"
 #include "town.h"
+#include "signalex_base.h"
 
 #include "table/strings.h"
 #include "table/railtypes.h"
@@ -971,6 +972,13 @@
 			uint mask = GetPresentSignals(tile) & SignalOnTrack(track);
 			SetSignalStates(tile, (GetSignalStates(tile) & ~mask) | ((HasBit(GetRailReservationTrackBits(tile), track) ? UINT_MAX : 0) & mask));
 		}
+		
+		/* at this point the tile has a signal. If it's an extended signal, update it */ 
+		if(SignalExMap::IsEnabled(tile)) { SignalEx::UpdateFromTile(tile); }
+#ifdef _ALL_SIGNALS_EXTENDED 
+		else { SignalEx::Update(SignalEx::Create(tile)); }
+#endif
+
 		MarkTileDirtyByTile(tile);
 		AddTrackToSignalBuffer(tile, track, _current_company);
 		YapfNotifyTrackLayoutChange(tile, track);
@@ -1220,9 +1228,15 @@
 
 		/* removed last signal from tile? */
 		if (GetPresentSignals(tile) == 0) {
+			/* destroy the extended signal if the tile has one */
+			if(SignalExMap::IsEnabled(tile)) {
+				SignalEx::Destroy(tile); // perform before the tile type is changed from RAIL_TILE_SIGNALS
+			}
 			SetSignalStates(tile, 0);
 			SetHasSignals(tile, false);
 			SetSignalVariant(tile, INVALID_TRACK, SIG_ELECTRIC); // remove any possible semaphores
+		} else {
+			SignalEx::UpdateFromTile(tile); // inform SignalEx object its tile signals have been updated
 		}
 
 		AddTrackToSignalBuffer(tile, track, GetTileOwner(tile));
Index: src/rail_map.h
===================================================================
--- src/rail_map.h	(revision 17607)
+++ src/rail_map.h	(working copy)
@@ -19,6 +19,7 @@
 #include "track_func.h"
 #include "tile_map.h"
 #include "signal_type.h"
+#include "signalex_type.h"
 
 
 /** Different types of Rail-related tiles */
Index: src/saveload/afterload.cpp
===================================================================
--- src/saveload/afterload.cpp	(revision 17607)
+++ src/saveload/afterload.cpp	(working copy)
@@ -42,6 +42,7 @@
 #include "../animated_tile_func.h"
 #include "../subsidy_base.h"
 #include "../subsidy_func.h"
+#include "../signalex_base.h"
 
 #include "table/strings.h"
 
@@ -1959,6 +1960,18 @@
 		}
 	}
 
+	/**
+	 *Clear flag bit used by signalex from the RAIL_TILE_SIGNALS signals on older save game versions
+	 *@todo actually needed?
+	 */
+	if (CheckSavegameVersion(128)) {
+		for (TileIndex t = 0; t < map_size; t++) {
+			if(IsTileType(t, MP_RAILWAY)) 
+				if(GetRailTileType(t) == RAIL_TILE_SIGNALS)
+					SignalExMap::SetBitsFlag(t,0);
+		}
+	}
+
 	AfterLoadLabelMaps();
 
 	GamelogPrintDebug(1);
Index: src/saveload/saveload.cpp
===================================================================
--- src/saveload/saveload.cpp	(revision 17607)
+++ src/saveload/saveload.cpp	(working copy)
@@ -48,7 +48,7 @@
 
 #include "saveload_internal.h"
 
-extern const uint16 SAVEGAME_VERSION = 127;
+extern const uint16 SAVEGAME_VERSION = 128;
 
 SavegameType _savegame_type; ///< type of savegame we are loading
 
@@ -1446,6 +1446,7 @@
 extern const ChunkHandler _cargopacket_chunk_handlers[];
 extern const ChunkHandler _autoreplace_chunk_handlers[];
 extern const ChunkHandler _labelmaps_chunk_handlers[];
+extern const ChunkHandler _signalex_chunk_handlers[];
 
 static const ChunkHandler * const _chunk_handlers[] = {
 	_gamelog_chunk_handlers,
@@ -1473,6 +1474,7 @@
 	_cargopacket_chunk_handlers,
 	_autoreplace_chunk_handlers,
 	_labelmaps_chunk_handlers,
+	_signalex_chunk_handlers,
 	NULL,
 };
 
Index: src/saveload/signalex_sl.cpp
===================================================================
--- src/saveload/signalex_sl.cpp	(revision 0)
+++ src/saveload/signalex_sl.cpp	(revision 0)
@@ -0,0 +1,36 @@
+/** @file signalex_sl.cpp Code handling saving and loading of extended signals */
+
+#include "../stdafx.h"
+#include "saveload_internal.h"
+#include "../signalex_base.h"
+#include <map>
+
+static const SaveLoad _signalex_desc[] = {
+	SLE_VAR(SignalEx, flags,			SLE_UINT32),
+	SLE_VAR(SignalEx, tile_id,			SLE_UINT32),
+	SLE_END()
+};
+
+static void Save_SGEX()
+{
+	SignalEx *s;
+
+	FOR_ALL_SIGNALEX(s) {
+		SlSetArrayIndex(s->index);
+		SlObject(s, _signalex_desc);
+	}
+}
+
+static void Load_SGEX()
+{
+	int index;
+
+	while ((index = SlIterateArray()) != -1) {
+		SignalEx *s = new (index) SignalEx();
+		SlObject(s, _signalex_desc);
+	}
+}
+
+extern const ChunkHandler _signalex_chunk_handlers[] = {
+	{ 'SGEX', Save_SGEX, Load_SGEX, NULL, CH_ARRAY | CH_LAST},
+};
Index: src/signalex.cpp
===================================================================
--- src/signalex.cpp	(revision 0)
+++ src/signalex.cpp	(revision 0)
@@ -0,0 +1,58 @@
+/** @file signalex.cpp Base for all extended signal handling. */
+
+#include "stdafx.h"
+#include "debug.h"
+#include "core/pool_func.hpp"
+#include "signalex_base.h"
+
+SignalExPool _signalex_pool("SignalEx");
+INSTANTIATE_POOL_METHODS(SignalEx)
+
+SignalEx::SignalEx() : flags(0), tile_id(0)
+{
+}
+SignalEx::SignalEx(TileIndex t) : flags(0), tile_id(t)
+{
+}
+SignalEx::~SignalEx()
+{
+}
+
+SignalEx* SignalEx::Create(TileIndex t)
+{
+	/* Ensure tile has signals */
+	assert(GetRailTileType(t) == RAIL_TILE_SIGNALS);
+	/* Ensure tile doesn't already have signalsEx */
+	assert(!SignalExMap::IsEnabled(t));
+
+	SignalEx* sx = new SignalEx(t);
+	SignalExID id = sx->index;
+
+	SignalExMap::Enable(t);
+	SignalExMap::SetID(t, id);
+
+	return sx;
+}
+
+void SignalEx::Destroy(TileIndex t)
+{
+	/* Ensure tile has signalsEx */
+	assert(SignalExMap::IsEnabled(t));
+	
+	SignalEx* sx = SignalEx::GetByTile(t);
+
+	SignalExMap::SetID(t, 0);
+	SignalExMap::Disable(t);
+	
+	delete sx;
+}
+
+void SignalEx::Update(SignalEx* sx)
+{
+	//Add in update routines for extensions, signal checks etc.  
+}
+
+void InitializeSignalEx()
+{
+	_signalex_pool.CleanPool();
+}
\ No newline at end of file
Index: src/signalex_base.h
===================================================================
--- src/signalex_base.h	(revision 0)
+++ src/signalex_base.h	(revision 0)
@@ -0,0 +1,114 @@
+/** @file signalex_base.h Types, classes and variables related to extended signals. */
+
+#ifndef SIGNALEXTENDED_BASE_H
+#define SIGNALEXTENDED_BASE_H
+
+#ifdef _DEBUG
+	#define _ALL_SIGNALS_EXTENDED 
+#endif
+
+#include "core\bitmath_func.hpp"
+#include "core/pool_type.hpp"
+#include "signal_type.h"
+#include "signalex_map.h"
+#include "signalex_type.h"
+
+typedef Pool<SignalEx, SignalExID, 512, 32768> SignalExPool;
+extern SignalExPool _signalex_pool;
+
+/**
+ * Defines signal extentions for a single tile.
+ * Stores additional information for signal extensions 
+ * seperatly from the tile array. All 4 posible signals
+ * can have seperate extensions. All extensions can be 
+ * active at the same time. 
+ *
+ * flags - @see SignalExFeature
+ *	flags: bit 7-0: Features in use for signal 0, 
+ *  flags: bit 15-8: Features in use for signal 1
+ *	flags: bit 23-16: Features in use for signal 2
+ *	flags: bit 32-24: Features in use for signal 3
+ *
+ * @warning Update the SaveLoad if adding variables to SignalEx. @see saveload\signalex_sl.cpp
+ */
+struct SignalEx : SignalExPool::PoolItem<&_signalex_pool> {
+	uint32 flags;		///< specifies what features are in-use for each signal.
+	TileIndex tile_id;	///< the tile location of this signalex (for reverse lookup)
+
+private:	
+	friend SignalExPool;
+	friend void Load_SGEX();	
+	
+	/** 
+	 * Forbidden to create or destroy SignalEx objects directly.
+	 * To create extended signals for a tile use Create(t) or
+	 * Destroy(t) to remove them. Loading and Pool management 
+	 * are exceptions.  
+	 */
+	SignalEx();
+	SignalEx(TileIndex t);
+	~SignalEx();
+
+public:
+	/** Get the SignalEx object from the pool using its ID 
+	*/
+	static FORCEINLINE SignalEx* GetByID(SignalExID id){
+		return _signalex_pool.Get(id);
+	}
+
+	/** Get the SignalEx object from the pool using a TileIndex 
+	 * @pre: SignalExMap::IsEnabled(t)
+	 */
+	static FORCEINLINE SignalEx* GetByTile(TileIndex t){
+		assert(SignalExMap::IsEnabled(t));
+		return _signalex_pool.Get(SignalExMap::GetID(t));
+	}
+
+	/** Update the SignalEx object bound to a given a tile
+	 * @param t - the tile to look up
+	 * @pre SignalExMap::IsEnabled(t)
+	 */
+	static FORCEINLINE void UpdateFromTile(TileIndex t){
+		/* Ensure tile has signalsEx */
+		assert(SignalExMap::IsEnabled(t));
+		SignalEx::Update(SignalEx::GetByTile(t));
+	}
+
+	/**
+	 * Instantiates a SignalEx object for a given tile
+	 * Enables SignalEx on the tile and stores the 
+	 * SignalExID in the tile as well. 
+	 * 
+	 * @param t - tile index to create SignalEx for
+	 * @return pointer to the new SignalEx object;
+	 *
+	 * @pre GetRailTileType(t) == RAIL_TILE_SIGNALS
+	 * @pre !SignalExMap::IsEnabled(t)
+	 */
+	static SignalEx* Create(TileIndex t);
+
+	/**
+	 * Destroys a SignalEx object for a given tile.
+	 * Disables SignalEx on the tile and clears the 
+	 * SignalExID from the tile as well. Called automatically 
+	 * just prior to the removal of the last signal from a tile.
+	 * @param t - tile index to remove SignalEx from
+	 * @pre SignalExMap::IsEnabled(t)
+	 */
+    static void	Destroy(TileIndex t);
+
+	/**
+	 * Update a SignalEx object after a tile alteration.
+	 * When the arrangment of signals on a tile is altered,
+	 * this function is called. Will not be called if the tile
+	 * loses all its signals. 
+	 * @param sx - the SignalEx object to update. 
+	 * @pre SignalExMap::IsEnabled(t)
+	 */
+	static void Update(SignalEx* sx);
+};
+
+#define FOR_ALL_SIGNALEX_FROM(var, start) FOR_ALL_ITEMS_FROM(SignalEx, signalex_index, var, start)
+#define FOR_ALL_SIGNALEX(var) FOR_ALL_SIGNALEX_FROM(var, 0)
+
+#endif /* SIGNALEXTENDED_BASE_H */
Index: src/signalex_map.h
===================================================================
--- src/signalex_map.h	(revision 0)
+++ src/signalex_map.h	(revision 0)
@@ -0,0 +1,119 @@
+/** @file signalex_map.h Hides the direct accesses to the map array with map accessors */
+
+#ifndef SIGNALEXTENDED_MAP_H
+#define SIGNALEXTENDED_MAP_H
+
+#include "core\bitmath_func.hpp"
+#include "rail_map.h"
+
+/**
+ * Tile SignalEx bit manipulation
+ */
+struct SignalExMap
+{
+private:
+	friend bool AfterLoadGame(); ///< Allow the afterloader to clear the flag bit directly on older savegames. 
+	static FORCEINLINE bool GetBitsFlag(TileIndex t)
+	{
+		return (GB(_m[t].m2, 15, 1) == 1U);
+	}
+
+	static FORCEINLINE void SetBitsFlag(TileIndex t, bool flag)
+	{
+		SB(_m[t].m2, 15, 1,(uint8)flag);
+	}
+
+	static FORCEINLINE SignalExID GetBitsID(TileIndex t)
+	{
+		return (SignalExID)((_me[t].m7) + (GB(_m[t].m6, 2,  4) << 8) + (GB(_m[t].m2, 12, 3) << 12));
+	}
+
+	static FORCEINLINE void SetBitsID(TileIndex t, SignalExID id)
+	{
+		SB(_me[t].m7, 0,  8, GB(id, 0,  8));
+		SB(_m[t].m6,  2,  4, GB(id, 8,  4));
+		SB(_m[t].m2,  12, 3, GB(id, 12, 3));
+	}
+	
+public:
+
+	/**
+	 * Returns whether the tile index has extended signals.
+	 * @param t the tile
+	 * @pre: GetRailTileType(t) == RAIL_TILE_SIGNALS
+	 * @return true if signalex enabled, false otherwise
+	 */
+	static FORCEINLINE bool IsEnabled(TileIndex t)
+	{
+		/* Ensure tile has signals */
+		assert(GetRailTileType(t) == RAIL_TILE_SIGNALS);
+		return (SignalExMap::GetBitsFlag(t) == 1);
+	}
+	/**
+	 * Get the index of the extended signal that is attached to the tile.
+	 * @param t the tile
+	 * @return SignalExID
+	 * @pre GetRailTileType(t) == RAIL_TILE_SIGNALS
+	 * @pre SignalExMap::IsEnabled(t)
+	 */
+	static inline SignalExID GetID(TileIndex t)
+	{
+		/*make sure the tile has a SignalExID */
+		assert(SignalExMap::IsEnabled(t));
+		return SignalExMap::GetBitsID(t);
+	}
+
+	/**
+	 * Set the index of the extended signal that is attached to the tile.
+	 * SignalExID stored in (m7:7-0, m6:5-2, m2:14-12) and forms 
+	 * a 15-bit index. (m2:15) defines whether signalEx is enabled. 
+	 * @param t the tile
+	 * @param t the signalex index
+	 * @pre SignalExMap::IsEnabled(t)
+	 */
+	static inline void SetID(TileIndex t, SignalExID id)
+	{
+		/* Ensure tile has a signal */
+		assert(SignalExMap::IsEnabled(t));
+
+		SignalExMap::SetBitsID(t, id);
+	}
+
+	/**
+	 * Enables SignalEx on a tile.
+	 * Sets the SignalEx flag  on the RAIL_TILE_SIGNALS tile to true 
+	 * and wipes the SignalExId to 0.
+	 * @param t the tile
+	 * @pre: GetRailTileType(t) == RAIL_TILE_SIGNALS
+	 * @warning does not create the SignalEx object in the pool
+	 * @warning clears the SignalExID from the tile
+	 */
+	static inline void Enable(TileIndex t)
+	{
+		/* Ensure tile has signals */
+		assert(GetRailTileType(t) == RAIL_TILE_SIGNALS);
+		
+		SignalExMap::SetBitsFlag(t, 1U);
+		SignalExMap::SetBitsID(t, 0);
+	}
+
+	/**
+	 * Disables SignalEx on a tile.
+	 * @param t the tile
+	 * @pre GetRailTileType(t) == RAIL_TILE_SIGNALS
+	 * @pre SignalExMap::IsEnabled(t)
+	 * @warning does not delete the SignalEx object from the pool
+	 */
+	static inline void Disable(TileIndex t)
+	{
+		/* Ensure tile has signals */
+		assert(GetRailTileType(t) == RAIL_TILE_SIGNALS);
+		assert(SignalExMap::IsEnabled(t));
+		
+		SignalExMap::SetBitsFlag(t, 0);
+		SignalExMap::SetBitsID(t, 0);
+		
+	}
+};
+
+#endif /* SIGNALEXTENDED_MAP_H */
Index: src/signalex_type.h
===================================================================
--- src/signalex_type.h	(revision 0)
+++ src/signalex_type.h	(revision 0)
@@ -0,0 +1,38 @@
+/** @file signalex_type.h Types related to extended signal information, restrictions and logic. */
+
+#ifndef SIGNALEXTENDED_TYPE_H
+#define SIGNALEXTENDED_TYPE_H
+
+typedef uint16 SignalExID;
+
+struct SignalEx;
+
+/**
+ * SignalEx Feature Enums
+ * defines to check what additional features are
+ * currently enabled for the individual signals (all 4)
+ */
+enum SignalExFeature {
+	SIGEXF_EXTENDED		= 1<<0, ///< The signal has extensions 
+	SIGEXF_ASPECTS		= 1<<1, ///< Signal can define multi-aspects
+	SIGEXF_THEATRES		= 1<<2, ///< Signal can define theatres/routes
+	SIGEXF_PROGRAMMED	= 1<<3,	///< Signal can be programmed
+};
+
+/**
+ * Extension: Multi-Aspect Signal States (place-holder)
+ * Defines various warning states for signals, which can be different
+ * to the actual Signal states (at least for now).
+ */
+enum SignalExAspects{
+	SIGEXA_DANGER	= 0, ///< Train should not pass
+	SIGEXA_CAUTION1 = 1, ///< Can pass, next signal is SIGEXT_DANGER
+	SIGEXA_CAUTION2 = 2, ///< Can pass, next signal is SIGEXT_CAUTION1
+	SIGEXA_DIVERGE1 = 3, ///< Can pass, path divergence after next signal
+	SIGEXA_DIVERGE2 = 4, ///< Can pass, next signal is SIGEXT_DIVERGE1
+	SIGEXA_CLEAR	= 5, ///< Can pass
+	SIGEXA_CALLON	= 6, ///< Can pass to couple to a consist
+	SIGEXA_SHUNT	= 7, ///< Can pass for shunting
+};
+
+#endif /* SIGNALEXTENDED_TYPE_H */