(svn r15216) -Feature: native support for Transport Tycoon (Original) savegames. Based on SVXConverter's source code and documentation by Roman Vetter

11 files changed, 887 insertions, 255 deletions

diff --git a/src/engine.cpp b/src/engine.cpp
index d35e9df54..ef6d63438 100644
--- a/src/engine.cpp
+++ b/src/engine.cpp
@@ -252,52 +252,57 @@ void SetYearEngineAgingStops()
 	}
 }
 
-void StartupEngines()
+void StartupOneEngine(Engine *e, Date aging_date)
 {
-	Engine *e;
-	/* Aging of vehicles stops, so account for that when starting late */
-	const Date aging_date = min(_date, ConvertYMDToDate(_year_engine_aging_stops, 0, 1));
-
-	FOR_ALL_ENGINES(e) {
-		const EngineInfo *ei = &e->info;
-		uint32 r;
+	const EngineInfo *ei = &e->info;
+	uint32 r;
+
+	e->age = 0;
+	e->flags = 0;
+	e->company_avail = 0;
+
+	/* The magic value of 729 days below comes from the NewGRF spec. If the
+	 * base intro date is before 1922 then the random number of days is not
+	 * added. */
+	r = Random();
+	e->intro_date = ei->base_intro <= ConvertYMDToDate(1922, 0, 1) ? ei->base_intro : (Date)GB(r, 0, 9) + ei->base_intro;
+	if (e->intro_date <= _date) {
+		e->age = (aging_date - e->intro_date) >> 5;
+		e->company_avail = (CompanyMask)-1;
+		e->flags |= ENGINE_AVAILABLE;
+	}
 
-		e->age = 0;
-		e->flags = 0;
-		e->company_avail = 0;
+	e->reliability_start = GB(r, 16, 14) + 0x7AE0;
+	r = Random();
+	e->reliability_max   = GB(r,  0, 14) + 0xBFFF;
+	e->reliability_final = GB(r, 16, 14) + 0x3FFF;
 
-		/* The magic value of 729 days below comes from the NewGRF spec. If the
-		 * base intro date is before 1922 then the random number of days is not
-		 * added. */
-		r = Random();
-		e->intro_date = ei->base_intro <= ConvertYMDToDate(1922, 0, 1) ? ei->base_intro : (Date)GB(r, 0, 9) + ei->base_intro;
-		if (e->intro_date <= _date) {
-			e->age = (aging_date - e->intro_date) >> 5;
-			e->company_avail = (CompanyMask)-1;
-			e->flags |= ENGINE_AVAILABLE;
-		}
+	r = Random();
+	e->duration_phase_1 = GB(r, 0, 5) + 7;
+	e->duration_phase_2 = GB(r, 5, 4) + ei->base_life * 12 - 96;
+	e->duration_phase_3 = GB(r, 9, 7) + 120;
 
-		e->reliability_start = GB(r, 16, 14) + 0x7AE0;
-		r = Random();
-		e->reliability_max   = GB(r,  0, 14) + 0xBFFF;
-		e->reliability_final = GB(r, 16, 14) + 0x3FFF;
+	e->reliability_spd_dec = ei->decay_speed << 2;
 
-		r = Random();
-		e->duration_phase_1 = GB(r, 0, 5) + 7;
-		e->duration_phase_2 = GB(r, 5, 4) + ei->base_life * 12 - 96;
-		e->duration_phase_3 = GB(r, 9, 7) + 120;
+	CalcEngineReliability(e);
 
-		e->reliability_spd_dec = ei->decay_speed << 2;
+	e->lifelength = ei->lifelength + _settings_game.vehicle.extend_vehicle_life;
 
-		CalcEngineReliability(e);
+	/* prevent certain engines from ever appearing. */
+	if (!HasBit(ei->climates, _settings_game.game_creation.landscape)) {
+		e->flags |= ENGINE_AVAILABLE;
+		e->company_avail = 0;
+	}
+}
 
-		e->lifelength = ei->lifelength + _settings_game.vehicle.extend_vehicle_life;
+void StartupEngines()
+{
+	Engine *e;
+	/* Aging of vehicles stops, so account for that when starting late */
+	const Date aging_date = min(_date, ConvertYMDToDate(_year_engine_aging_stops, 0, 1));
 
-		/* prevent certain engines from ever appearing. */
-		if (!HasBit(ei->climates, _settings_game.game_creation.landscape)) {
-			e->flags |= ENGINE_AVAILABLE;
-			e->company_avail = 0;
-		}
+	FOR_ALL_ENGINES(e) {
+		StartupOneEngine(e, aging_date);
 	}
 
 	/* Update the bitmasks for the vehicle lists */
diff --git a/src/engine_func.h b/src/engine_func.h
index df0ca0d99..eccdff784 100644
--- a/src/engine_func.h
+++ b/src/engine_func.h
@@ -27,5 +27,6 @@ bool IsEngineRefittable(EngineID engine);
 CargoID GetEngineCargoType(EngineID engine);
 void SetCachedEngineCounts();
 void SetYearEngineAgingStops();
+void StartupOneEngine(Engine *e, Date aging_date);
 
 #endif /* ENGINE_H */
diff --git a/src/gamelog.cpp b/src/gamelog.cpp
index a9d9d4bd4..145351ba9 100644
--- a/src/gamelog.cpp
+++ b/src/gamelog.cpp
@@ -195,6 +195,10 @@ void GamelogPrint(GamelogPrintProc *proc)
 								GB(lc->oldver.version, 8, 16), GB(lc->oldver.version, 0, 8));
 							break;
 
+						case SGT_TTO:
+							AddDebugText(buf, "TTO savegame");
+							break;
+
 						case SGT_TTD:
 							AddDebugText(buf, "TTD savegame");
 							break;
diff --git a/src/saveload/afterload.cpp b/src/saveload/afterload.cpp
index bbff67644..acfe903dd 100644
--- a/src/saveload/afterload.cpp
+++ b/src/saveload/afterload.cpp
@@ -327,7 +327,7 @@ static void FixOwnerOfRailTrack(TileIndex t)
 	if (IsLevelCrossingTile(t)) {
 		/* else change the crossing to normal road (road vehicles won't care) */
 		MakeRoadNormal(t, GetCrossingRoadBits(t), GetRoadTypes(t), GetTownIndex(t),
-		GetRoadOwner(t, ROADTYPE_ROAD), GetRoadOwner(t, ROADTYPE_TRAM), GetRoadOwner(t, ROADTYPE_HWAY));
+			GetRoadOwner(t, ROADTYPE_ROAD), GetRoadOwner(t, ROADTYPE_TRAM), GetRoadOwner(t, ROADTYPE_HWAY));
 		return;
 	}
 
@@ -356,7 +356,6 @@ bool AfterLoadGame()
 		Station *st;
 		FOR_ALL_STATIONS(st) {
 			if (st->train_tile != 0 && st->trainst_h == 0) {
-				extern SavegameType _savegame_type;
 				uint n = _savegame_type == SGT_OTTD ? 4 : 3; // OTTD uses 4 bits per dimensions, TTD 3 bits
 				uint w = GB(st->trainst_w, n, n);
 				uint h = GB(st->trainst_w, 0, n);
diff --git a/src/saveload/oldloader.cpp b/src/saveload/oldloader.cpp
index 4b7af3a42..2411a675e 100644
--- a/src/saveload/oldloader.cpp
+++ b/src/saveload/oldloader.cpp
@@ -17,12 +17,13 @@
 #include "oldloader.h"
 
 enum {
-	HEADER_SIZE = 49,
+	TTO_HEADER_SIZE = 41,
+	TTD_HEADER_SIZE = 49,
 };
 
 uint32 _bump_assert_value;
 
-static inline OldChunkType GetOldChunkType(OldChunkType type)     {return (OldChunkType)GB(type, 0, 8);}
+static inline OldChunkType GetOldChunkType(OldChunkType type)     {return (OldChunkType)GB(type, 0, 4);}
 static inline OldChunkType GetOldChunkVarType(OldChunkType type)  {return (OldChunkType)(GB(type, 8, 8) << 8);}
 static inline OldChunkType GetOldChunkFileType(OldChunkType type) {return (OldChunkType)(GB(type, 16, 8) << 16);}
 
@@ -101,12 +102,17 @@ byte ReadByte(LoadgameState *ls)
  */
 bool LoadChunk(LoadgameState *ls, void *base, const OldChunks *chunks)
 {
-	const OldChunks *chunk = chunks;
 	byte *base_ptr = (byte*)base;
 
-	while (chunk->type != OC_END) {
+	for (const OldChunks *chunk = chunks; chunk->type != OC_END; chunk++) {
+		if (((chunk->type & OC_TTD) && (_savegame_type == SGT_TTO)) ||
+				((chunk->type & OC_TTO) && (_savegame_type != SGT_TTO))) {
+			/* TTD(P)-only chunk, but TTO savegame || TTO-only chunk, but TTD/TTDP savegame */
+			continue;
+		}
+
 		byte *ptr = (byte*)chunk->ptr;
-		if ((chunk->type & OC_DEREFERENCE_POINTER) != 0) ptr = *(byte**)ptr;
+		if (chunk->type & OC_DEREFERENCE_POINTER) ptr = *(byte**)ptr;
 
 		for (uint i = 0; i < chunk->amount; i++) {
 			if (ls->failed) return false;
@@ -164,8 +170,6 @@ bool LoadChunk(LoadgameState *ls, void *base, const OldChunks *chunks)
 				if (chunk->amount > 1 && chunk->ptr != NULL) ptr += CalcOldVarLen(chunk->type);
 			}
 		}
-
-		chunk++;
 	}
 
 	return true;
@@ -194,30 +198,72 @@ static void InitLoading(LoadgameState *ls)
 	_settings_game.construction.freeform_edges = false; // disable so we can convert map array (SetTileType is still used)
 }
 
-
-
 /**
  * Verifies the title has a valid checksum
  * @param title title and checksum
  * @return true iff the title is valid
- * @note the title (incl. checksum) has to be at least 49 (HEADER_SIZE) bytes long!
+ * @note the title (incl. checksum) has to be at least 41/49 (HEADER_SIZE) bytes long!
  */
-static bool VerifyOldNameChecksum(char *title)
+static bool VerifyOldNameChecksum(char *title, uint len)
 {
 	uint16 sum = 0;
-	for (uint i = 0; i < HEADER_SIZE - 2; i++) {
+	for (uint i = 0; i < len - 2; i++) {
 		sum += title[i];
 		sum = ROL(sum, 1);
 	}
 
 	sum ^= 0xAAAA; // computed checksum
 
-	uint16 sum2 = title[HEADER_SIZE - 2]; // checksum in file
-	SB(sum2, 8, 8, title[HEADER_SIZE - 1]);
+	uint16 sum2 = title[len - 2]; // checksum in file
+	SB(sum2, 8, 8, title[len - 1]);
 
 	return sum == sum2;
 }
 
+static inline bool CheckOldSavegameType(FILE *f, char *temp, const char *last, uint len)
+{
+	assert(last - temp + 1 >= len);
+
+	fseek(f, 0, SEEK_SET);
+	if (fread(temp, 1, len, f) != len) {
+		temp[0] = '\0'; // if reading failed, make the name empty
+		return false;
+	}
+
+	bool ret = VerifyOldNameChecksum(temp, len);
+	temp[len - 2] = '\0'; // name is nul-terminated in savegame, but it's better to be sure
+
+	return ret;
+}
+
+assert_compile(TTD_HEADER_SIZE >= TTO_HEADER_SIZE);
+static SavegameType DetermineOldSavegameType(FILE *f, char *title, const char *last)
+{
+	char temp[TTD_HEADER_SIZE];
+
+	SavegameType type = SGT_TTO;
+
+	if (!CheckOldSavegameType(f, temp, lastof(temp), TTO_HEADER_SIZE)) {
+		type = SGT_TTD;
+		if (!CheckOldSavegameType(f, temp, lastof(temp), TTD_HEADER_SIZE)) {
+			type = SGT_INVALID;
+		}
+	}
+
+	if (title != NULL) {
+		switch (type) {
+			case SGT_TTO: title = strecpy(title, "(TTO) ", last);    break;
+			case SGT_TTD: title = strecpy(title, "(TTD) ", last);    break;
+			default:      title = strecpy(title, "(broken) ", last); break;
+		}
+		title = strecpy(title, temp, last);
+	}
+
+	return type;
+}
+
+typedef bool LoadOldMainProc(LoadgameState *ls);
+
 bool LoadOldSaveGame(const char *file)
 {
 	LoadgameState ls;
@@ -234,8 +280,19 @@ bool LoadOldSaveGame(const char *file)
 		return false;
 	}
 
-	char temp[HEADER_SIZE];
-	if (fread(temp, 1, HEADER_SIZE, ls.file) != HEADER_SIZE || !VerifyOldNameChecksum(temp) || !LoadOldMain(&ls)) {
+	SavegameType type = DetermineOldSavegameType(ls.file, NULL, NULL);
+
+	LoadOldMainProc *proc = NULL;
+
+	switch (type) {
+		case SGT_TTO: proc = &LoadTTOMain; break;
+		case SGT_TTD: proc = &LoadTTDMain; break;
+		default: break;
+	}
+
+	_savegame_type = type;
+
+	if (proc == NULL || !proc(&ls)) {
 		SetSaveLoadError(STR_GAME_SAVELOAD_ERROR_DATA_INTEGRITY_CHECK_FAILED);
 		fclose(ls.file);
 		return false;
@@ -249,23 +306,16 @@ bool LoadOldSaveGame(const char *file)
 void GetOldSaveGameName(const char *path, const char *file, char *title, const char *last)
 {
 	char filename[MAX_PATH];
-	char temp[HEADER_SIZE];
 
 	snprintf(filename, lengthof(filename), "%s" PATHSEP "%s", path, file);
 	FILE *f = fopen(filename, "rb");
-	temp[0] = '\0'; // name is nul-terminated in savegame ...
 
 	if (f == NULL) {
 		*title = '\0';
 		return;
 	}
 
-	bool broken = (fread(temp, 1, HEADER_SIZE, f) != HEADER_SIZE || !VerifyOldNameChecksum(temp));
-
-	temp[HEADER_SIZE - 2] = '\0'; // ... but it's better to be sure
-
-	if (broken) title = strecpy(title, "(broken) ", last);
-	title = strecpy(title, temp, last);
+	DetermineOldSavegameType(f, title, last);
 
 	fclose(f);
 }
diff --git a/src/saveload/oldloader.h b/src/saveload/oldloader.h
index 5cde06cc5..6bee5d5f6 100644
--- a/src/saveload/oldloader.h
+++ b/src/saveload/oldloader.h
@@ -34,7 +34,11 @@ enum OldChunkType {
 	OC_NULL      = 1,
 	OC_CHUNK     = 2,
 	OC_ASSERT    = 3,
-	/* 8 bits allocated (256 max) */
+	/* 4 bits allocated (16 max) */
+
+	OC_TTD       = 1 << 4, ///< chunk is valid ONLY for TTD savegames
+	OC_TTO       = 1 << 5, ///< -//- TTO (default in neither of these)
+	/* 4 bits allocated */
 
 	OC_VAR_I8    = 1 << 8,
 	OC_VAR_U8    = 2 << 8,
@@ -91,7 +95,8 @@ extern uint _bump_assert_value;
 byte ReadByte(LoadgameState *ls);
 bool LoadChunk(LoadgameState *ls, void *base, const OldChunks *chunks);
 
-bool LoadOldMain(LoadgameState *ls);
+bool LoadTTDMain(LoadgameState *ls);
+bool LoadTTOMain(LoadgameState *ls);
 
 static inline uint16 ReadUint16(LoadgameState *ls)
 {
@@ -114,11 +119,13 @@ static inline uint32 ReadUint32(LoadgameState *ls)
  *  - OCL_CHUNK: load an other proc to load a part of the savegame, 'amount' times
  *  - OCL_ASSERT: to check if we are really at the place we expect to be.. because old savegames are too binary to be sure ;)
  */
-#define OCL_SVAR(type, base, offset)         { type,          1, NULL,    (uint)cpp_offsetof(base, offset), NULL }
-#define OCL_VAR(type, amount, pointer)       { type,     amount, pointer, 0,                      NULL }
-#define OCL_END()                                   { OC_END,        0, NULL,    0,                      NULL }
-#define OCL_NULL(amount)                            { OC_NULL,  amount, NULL,    0,                      NULL }
-#define OCL_CHUNK(amount, proc)                     { OC_CHUNK, amount, NULL,    0,                      proc }
-#define OCL_ASSERT(size)                            { OC_ASSERT,     1, NULL, size,                      NULL }
+#define OCL_SVAR(type, base, offset)         { type,                 1,    NULL, (uint)cpp_offsetof(base, offset), NULL }
+#define OCL_VAR(type, amount, pointer)       { type,            amount, pointer,    0,                             NULL }
+#define OCL_END()                            { OC_END,               0,    NULL,    0,                             NULL }
+#define OCL_CNULL(type, amount)              { OC_NULL | type,  amount,    NULL,    0,                             NULL }
+#define OCL_CCHUNK(type, amount, proc)       { OC_CHUNK | type, amount,    NULL,    0,                             proc }
+#define OCL_ASSERT(type, size)               { OC_ASSERT | type,     1,    NULL, size,                             NULL }
+#define OCL_NULL(amount)        OCL_CNULL((OldChunkType)0, amount)
+#define OCL_CHUNK(amount, proc) OCL_CCHUNK((OldChunkType)0, amount, proc)
 
 #endif /* OLDLOADER_H */
diff --git a/src/saveload/ttdloader.cpp b/src/saveload/oldloader_sl.cpp
index d239a7968..0b449ca90 100644
--- a/src/saveload/ttdloader.cpp
+++ b/src/saveload/oldloader_sl.cpp
@@ -1,6 +1,6 @@
 /* $Id$ */
 
-/** @file oldloader.cpp Loading of old TTD(patch) savegames. */
+/** @file oldloader_sl.cpp Chunks and fix-ups for TTO/TTD/TTDP savegames. TTO loader code is based on SVXConverter by Roman Vetter. */
 
 #include "../stdafx.h"
 #include "../station_map.h"
@@ -24,21 +24,27 @@
 #include "../string_func.h"
 #include "../core/mem_func.hpp"
 #include "../core/alloc_type.hpp"
-
-#include "table/strings.h"
-
-#include "oldloader.h"
 #include "saveload_internal.h"
+#include "oldloader.h"
 
+#include "table/strings.h"
+#include "../table/engines.h"
 
-extern SavegameType _savegame_type;
-extern uint32 _ttdp_version;
 static bool   _read_ttdpatch_flags;
 
 static uint8  *_old_map3;
 
 void FixOldMapArray()
 {
+	/* TTO/TTD/TTDP savegames could have buoys at tile 0
+	 * (without assigned station struct) */
+	MemSetT(&_m[0], 0);
+	SetTileType(0, MP_WATER);
+	SetTileOwner(0, OWNER_WATER);
+}
+
+static void FixTTDMapArray()
+{
 	/* _old_map3 is moved to _m::m3 and _m::m4 */
 	for (TileIndex t = 0; t < OLD_MAP_SIZE; t++) {
 		_m[t].m3 = _old_map3[t * 2];
@@ -89,11 +95,7 @@ void FixOldMapArray()
 		}
 	}
 
-	/* Some old TTD(Patch) savegames could have buoys at tile 0
-	 * (without assigned station struct) */
-	MemSetT(&_m[0], 0);
-	SetTileType(0, MP_WATER);
-	SetTileOwner(0, OWNER_WATER);
+	FixOldMapArray();
 }
 
 extern uint32 GetOldTownName(uint32 townnameparts, byte old_town_name_type);
@@ -111,7 +113,7 @@ void FixOldTowns()
 	}
 }
 
-StringID *_old_vehicle_names = NULL;
+StringID *_old_vehicle_names;
 
 void FixOldVehicles()
 {
@@ -153,13 +155,271 @@ void FixOldVehicles()
 	}
 }
 
+static bool FixTTOMapArray()
+{
+	for (TileIndex t = 0; t < OLD_MAP_SIZE; t++) {
+		TileType tt = GetTileType(t);
+
+		switch (tt) {
+			case MP_CLEAR:
+				break;
+
+			case MP_RAILWAY:
+			case 11: // monorail
+				if (tt == 11) {
+					_m[t].m3 = 1; // rail type = monorail
+					_m[t].type_height &= 0x1F; // -> MP_RAILWAY
+					_m[t].m2 = 1; // set monorail ground to RAIL_GROUND_GRASS
+				}
+				switch (GB(_m[t].m5, 6, 2)) {
+					case 0: // RAIL_TILE_NORMAL
+						break;
+					case 1: // RAIL_TILE_SIGNALS
+						_m[t].m4 = (~_m[t].m5 & 1) << 2;        // signal variant (present only in OTTD)
+						SB(_m[t].m2, 6, 2, GB(_m[t].m5, 3, 2)); // signal status
+						_m[t].m3 |= 0xC0;                       // both signals are present
+						_m[t].m5 = HasBit(_m[t].m5, 5) ? 2 : 1; // track direction (only X or Y)
+						_m[t].m5 |= 0x40;                       // RAIL_TILE_SIGNALS
+						break;
+					case 3: // RAIL_TILE_DEPOT
+						_m[t].m2 = 0;
+						break;
+					default:
+						return false;
+				}
+				break;
+
+			case MP_ROAD: // road (depot) or level crossing
+				switch (GB(_m[t].m5, 4, 4)) {
+					case 0: // ROAD_TILE_NORMAL
+						if (_m[t].m2 == 4) _m[t].m2 = 5; // 'small trees' -> ROADSIDE_TREES
+						break;
+					case 1: // ROAD_TILE_CROSSING (there aren't monorail crossings in TTO)
+						_m[t].m3 = _m[t].m1; // set owner of road = owner of rail
+						break;
+					case 2: // ROAD_TILE_DEPOT
+						break;
+					default:
+						return false;
+				}
+				break;
+
+			case MP_HOUSE:
+				_m[t].m3 = _m[t].m2 & 0xC0;    // construction stage
+				_m[t].m2 &= 0x3F;              // building type
+				if (_m[t].m2 >= 5) _m[t].m2++; // skip "large office block on snow"
+				break;
+
+			case MP_TREES:
+				_m[t].m3 = GB(_m[t].m5, 3, 3); // type of trees
+				_m[t].m5 &= 0xC7;              // number of trees and growth status
+				break;
+
+			case MP_STATION:
+				_m[t].m3 = (_m[t].m5 >= 0x08 && _m[t].m5 <= 0x0F) ? 1 : 0; // monorail -> 1, others 0 (rail, road, airport, dock)
+				if (_m[t].m5 >= 8) _m[t].m5 -= 8; // shift for monorail
+				if (_m[t].m5 >= 0x42) _m[t].m5++; // skip heliport
+				break;
 
-/* The savegames has some hard-coded pointers, because it always enters the same
- *  piece of memory.. we don't.. so we need to remap ;)
- * Old Towns are 94 bytes big
- * Old Orders are 2 bytes big */
-#define REMAP_TOWN_IDX(x) ((x) - (0x0459154 - 0x0458EF0)) / 94
-#define REMAP_ORDER_IDX(x) ((x) - (0x045AB08 - 0x0458EF0)) / 2
+			case MP_WATER:
+				_m[t].m3 = _m[t].m2 = 0;
+				break;
+
+			case MP_VOID:
+				_m[t].m2 = _m[t].m3 = _m[t].m5 = 0;
+				break;
+
+			case MP_INDUSTRY:
+				_m[t].m3 = 0;
+				switch (_m[t].m5) {
+					case 0x24: // farm silo
+						_m[t].m5 = 0x25;
+						break;
+					case 0x25: case 0x27: // farm
+					case 0x28: case 0x29: case 0x2A: case 0x2B: // factory
+						_m[t].m5--;
+						break;
+					default:
+						if (_m[t].m5 >= 0x2C) _m[t].m5 += 3; // iron ore mine, steel mill or bank
+						break;
+				}
+				break;
+
+			case MP_TUNNELBRIDGE:
+				if (HasBit(_m[t].m5, 7)) { // bridge
+					byte m5 = _m[t].m5;
+					_m[t].m5 = m5 & 0xE1; // copy bits 7..5, 1
+					if (GB(m5, 1, 2) == 1) _m[t].m5 |= 0x02; // road bridge
+					if (GB(m5, 1, 2) == 3) _m[t].m2 |= 0xA0; // monorail bridge -> tubular, steel bridge
+					if (!HasBit(m5, 6)) { // bridge head
+						_m[t].m3 = (GB(m5, 1, 2) == 3) ? 1 : 0; // track subtype (1 for monorail, 0 for others)
+					} else { // middle bridge part
+						_m[t].m3 = HasBit(m5, 2) ? 0x10 : 0;  // track subtype on bridge
+						if (GB(m5, 3, 2) == 3) _m[t].m3 |= 1; // track subtype under bridge
+						if (GB(m5, 3, 2) == 1) _m[t].m5 |= 0x08; // set for road/water under (0 for rail/clear)
+					}
+				} else { // tunnel entrance/exit
+					_m[t].m2 = 0;
+					_m[t].m3 = HasBit(_m[t].m5, 3); // monorail
+					_m[t].m5 &= HasBit(_m[t].m5, 3) ? 0x03 : 0x07 ; // direction, transport type (== 0 for rail)
+				}
+				break;
+
+			case MP_UNMOVABLE:
+				_m[t].m2 = 0;
+				_m[t].m3 = 0;
+				break;
+
+			default:
+				return false;
+
+		}
+	}
+
+	FixOldMapArray();
+
+	return true;
+}
+
+static Engine *_old_engines;
+
+static bool FixTTOEngines()
+{
+	/** TTD->TTO remapping of engines; 255 means there is no equivalent. SVXConverter uses (almost) the same table. */
+	static const EngineID ttd_to_tto[] = {
+		  0, 255, 255, 255, 255, 255, 255, 255,   5,   7,   8,   9,  10,  11,  12,  13,
+		255, 255, 255, 255, 255, 255,  15,  16,  17,  18,  19,  20,  21,  22,  23,  24,
+		25,   26,  27,  28,  29,  30, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+		255, 255, 255, 255, 255, 255, 255,  31, 255,  32,  33,  34,  35,  36,  37,  38,
+		 39,  40,  41,  42, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+		255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+		255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+		255, 255, 255, 255,  44,  45,  46, 255, 255, 255, 255,  47,  48, 255,  49,  50,
+		255, 255, 255, 255,  51,  52, 255,  53,  54, 255,  55,  56, 255,  57,  58, 255,
+		 59,  60,   255,61,  62, 255,  63,  64, 255,  65,  66, 255, 255, 255, 255, 255,
+		255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+		255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+		255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,  67,  68,  69,  70,
+		 71, 255, 255,  76,  77, 255, 255,  78,  79,  80,  81,  82,  83,  84,  85,  86,
+		 87,  88,  89,  90,  91,  92,  93,  94,  95,  96,  97,  98,  99, 100, 101, 255,
+		255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 102, 255, 255
+	};
+
+	/** TTO->TTD remapping of engines. SVXConverter uses the same table. */
+	static const EngineID tto_to_ttd[] = {
+		  0,   0,   8,   8,   8,   8,   8,   9,  10,  11,  12,  13,  14,  15,  15,  22,
+		 23,  24,  25,  26,  27,  28,  29,  30,  31,  32,  33,  34,  35,  36,  37,  55,
+		 57,  58,  59,  60,  61,  62,  63,  64,  65,  66,  67, 116, 116, 117, 118, 123,
+		124, 126, 127, 132, 133, 135, 136, 138, 139, 141, 142, 144, 145, 147, 148, 150,
+		151, 153, 154, 204, 205, 206, 207, 208, 211, 212, 211, 212, 211, 212, 215, 216,
+		217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232,
+		233, 234, 235, 236, 237, 238, 253
+	};
+
+	Vehicle *v;
+	FOR_ALL_VEHICLES(v) {
+		if (v->engine_type >= lengthof(tto_to_ttd)) return false;
+		v->engine_type = tto_to_ttd[v->engine_type];
+	}
+
+	/* Load the default engine set. Many of them will be overriden later */
+	uint j = 0;
+	for (uint i = 0; i < lengthof(_orig_rail_vehicle_info); i++, j++) new (GetTempDataEngine(j)) Engine(VEH_TRAIN, i);
+	for (uint i = 0; i < lengthof(_orig_road_vehicle_info); i++, j++) new (GetTempDataEngine(j)) Engine(VEH_ROAD, i);
+	for (uint i = 0; i < lengthof(_orig_ship_vehicle_info); i++, j++) new (GetTempDataEngine(j)) Engine(VEH_SHIP, i);
+	for (uint i = 0; i < lengthof(_orig_aircraft_vehicle_info); i++, j++) new (GetTempDataEngine(j)) Engine(VEH_AIRCRAFT, i);
+
+	Date aging_date = min(_date + DAYS_TILL_ORIGINAL_BASE_YEAR, ConvertYMDToDate(2050, 0, 1));
+
+	for (EngineID i = 0; i < 256; i++) {
+		int oi = ttd_to_tto[i];
+		Engine *e = GetTempDataEngine(i);
+
+		if (oi == 255) {
+			/* Default engine is used */
+			_date += DAYS_TILL_ORIGINAL_BASE_YEAR;
+			StartupOneEngine(e, aging_date);
+			e->intro_date -= DAYS_TILL_ORIGINAL_BASE_YEAR;
+			_date -= DAYS_TILL_ORIGINAL_BASE_YEAR;
+
+			/* Make sure for example monorail and maglev are available when they should be */
+			if (_date >= e->intro_date && HasBit(e->info.climates, 0)) {
+				e->flags |= ENGINE_AVAILABLE;
+				e->company_avail = (CompanyMask)0xFF;
+				e->age = _date > e->intro_date ? (_date - e->intro_date) / 30 : 0;
+			}
+		} else {
+			/* Using data from TTO savegame */
+			Engine *oe = &_old_engines[oi];
+
+			e->intro_date          = oe->intro_date;
+			e->age                 = oe->age;
+			e->reliability         = oe->reliability;
+			e->reliability_spd_dec = oe->reliability_spd_dec;
+			e->reliability_start   = oe->reliability_start;
+			e->reliability_max     = oe->reliability_max;
+			e->reliability_final   = oe->reliability_final;
+			e->duration_phase_1    = oe->duration_phase_1;
+			e->duration_phase_2    = oe->duration_phase_2;
+			e->duration_phase_3    = oe->duration_phase_3;
+			e->lifelength          = oe->lifelength;
+			e->flags               = oe->flags;
+
+			e->company_avail = 0;
+
+			/* One or more engines were remapped to this one. Make this engine available
+			 * if at least one of them was available. */
+			for (uint j = 0; j < lengthof(tto_to_ttd); j++) {
+				if (tto_to_ttd[j] == i && _old_engines[j].company_avail != 0) {
+					e->company_avail = (CompanyMask)0xFF;
+					e->flags |= ENGINE_AVAILABLE;
+					break;
+				}
+			}
+
+			e->preview_company_rank = 0;
+			e->preview_wait = 0;
+			e->name = NULL;
+
+			e->info.climates = 1;
+		}
+	}
+
+	return true;
+}
+
+static void FixTTOCompanies()
+{
+	Company *c;
+	FOR_ALL_COMPANIES(c) {
+		c->cur_economy.company_value = CalculateCompanyValue(c); // company value history is zeroed
+	}
+}
+
+static inline byte RemapTTOColour(byte tto)
+{
+	/** Lossy remapping of TTO colours to TTD colours. SVXConverter uses the same conversion. */
+	static const byte tto_colour_remap[] = {
+		COLOUR_DARK_BLUE,  COLOUR_GREY,       COLOUR_YELLOW,     COLOUR_RED,
+		COLOUR_PURPLE,     COLOUR_DARK_GREEN, COLOUR_ORANGE,     COLOUR_PALE_GREEN,
+		COLOUR_BLUE,       COLOUR_GREEN,      COLOUR_CREAM,      COLOUR_BROWN,
+		COLOUR_WHITE,      COLOUR_LIGHT_BLUE, COLOUR_MAUVE,      COLOUR_PINK
+	};
+
+	if ((size_t)tto >= lengthof(tto_colour_remap)) return COLOUR_GREY; // this shouldn't happen
+
+	return tto_colour_remap[tto];
+}
+
+static inline uint RemapTownIndex(uint x)
+{
+	return _savegame_type == SGT_TTO ? (x - 0x264) / 78 : (x - 0x264) / 94;
+}
+
+static inline uint RemapOrderIndex(uint x)
+{
+	return _savegame_type == SGT_TTO ? (x - 0x1AC4) / 2 : (x - 0x1C18) / 2;
+}
 
 extern TileIndex *_animated_tile_list;
 extern uint _animated_tile_count;
@@ -177,6 +437,11 @@ static void ReadTTDPatchFlags()
 
 	_read_ttdpatch_flags = true;
 
+	if (_savegame_type == SGT_TTO) {
+		_old_vehicle_multiplier = 1;
+		return;
+	}
+
 	/* TTDPatch misuses _old_map3 for flags.. read them! */
 	_old_vehicle_multiplier = _old_map3[0];
 	/* Somehow.... there was an error in some savegames, so 0 becomes 1
@@ -249,24 +514,32 @@ static const OldChunks town_chunk[] = {
 	OCL_SVAR(  OC_UINT8, Town, pct_pass_transported ),
 	OCL_SVAR(  OC_UINT8, Town, pct_mail_transported ),
 
-	OCL_SVAR( OC_UINT16, Town, new_act_food ),
-	OCL_SVAR( OC_UINT16, Town, new_act_water ),
-	OCL_SVAR( OC_UINT16, Town, act_food ),
-	OCL_SVAR( OC_UINT16, Town, act_water ),
+	OCL_SVAR( OC_TTD | OC_UINT16, Town, new_act_food ),
+	OCL_SVAR( OC_TTD | OC_UINT16, Town, new_act_water ),
+	OCL_SVAR( OC_TTD | OC_UINT16, Town, act_food ),
+	OCL_SVAR( OC_TTD | OC_UINT16, Town, act_water ),
 
 	OCL_SVAR(  OC_UINT8, Town, road_build_months ),
 	OCL_SVAR(  OC_UINT8, Town, fund_buildings_months ),
 
-	OCL_NULL( 8 ),         ///< some junk at the end of the record
+	OCL_CNULL( OC_TTD, 8 ),         ///< some junk at the end of the record
 
 	OCL_END()
 };
+
 static bool LoadOldTown(LoadgameState *ls, int num)
 {
 	Town *t = new (num) Town();
 	if (!LoadChunk(ls, t, town_chunk)) return false;
 
-	if (t->xy == 0) t->xy = INVALID_TILE;
+	if (t->xy != 0) {
+		if (_savegame_type == SGT_TTO) {
+			/* 0x10B6 is auto-generated name, others are custom names */
+			t->townnametype = t->townnametype == 0x10B6 ? 0x20C1 : t->townnametype + 0x2A00;
+		}
+	} else {
+		t->xy = INVALID_TILE;
+	}
 
 	return true;
 }
@@ -283,11 +556,11 @@ static bool LoadOldOrder(LoadgameState *ls, int num)
 
 	new (num) Order(UnpackOldOrder(_old_order));
 
-	/* Relink the orders to eachother (in TTD(Patch) the orders for one
-	vehicle are behind eachother, with an invalid order (OT_NOTHING) as indication that
-	it is the last order */
-	if (num > 0 && GetOrder(num)->IsValid())
+	/* Relink the orders to eachother (in the orders for one vehicle are behind eachother,
+	 * with an invalid order (OT_NOTHING) as indication that it is the last order */
+	if (num > 0 && GetOrder(num)->IsValid()) {
 		GetOrder(num - 1)->next = GetOrder(num);
+	}
 
 	return true;
 }
@@ -317,7 +590,7 @@ static bool LoadOldAnimTileList(LoadgameState *ls, int num)
 
 static const OldChunks depot_chunk[] = {
 	OCL_SVAR(   OC_TILE, Depot, xy ),
-	OCL_VAR ( OC_UINT32,   1, &_old_town_index ),
+	OCL_VAR ( OC_UINT32,                1, &_old_town_index ),
 	OCL_END()
 };
 
@@ -327,7 +600,7 @@ static bool LoadOldDepot(LoadgameState *ls, int num)
 	if (!LoadChunk(ls, d, depot_chunk)) return false;
 
 	if (d->xy != 0) {
-		GetDepot(num)->town_index = REMAP_TOWN_IDX(_old_town_index);
+		d->town_index = RemapTownIndex(_old_town_index);
 	} else {
 		d->xy = INVALID_TILE;
 	}
@@ -345,10 +618,24 @@ static const OldChunks price_chunk[] = {
 
 static bool LoadOldPrice(LoadgameState *ls, int num)
 {
+	if (_savegame_type == SGT_TTO && num == 25) {
+		/* clear_fields == build_road_depot (TTO didn't have this price) */
+		((Money*)&_price)[25] = ((Money*)&_price)[6];
+		_price_frac[25] = _price_frac[6];
+		return true;
+	}
+
 	if (!LoadChunk(ls, NULL, price_chunk)) return false;
 
+	if (_savegame_type == SGT_TTO) {
+		/* base prices are different in these two cases */
+		if (num == 15) _old_price = ClampToI32(((Money)_old_price) * 20 / 3); // build_railvehicle
+		if (num == 17) _old_price = ClampToI32(((Money)_old_price) * 10);     // aircraft_base
+	}
+
+
 	/* We use a struct to store the prices, but they are ints in a row..
-	so just access the struct as an array of int32's */
+	 * so just access the struct as an array of int32s */
 	((Money*)&_price)[num] = _old_price;
 	_price_frac[num] = _old_price_frac;
 
@@ -365,15 +652,33 @@ static const OldChunks cargo_payment_rate_chunk[] = {
 
 static bool LoadOldCargoPaymentRate(LoadgameState *ls, int num)
 {
+	if (_savegame_type == SGT_TTO && num == 11) { // TTD has 1 more cargo type
+		_cargo_payment_rates[num] = _cargo_payment_rates[9];
+		_cargo_payment_rates_frac[num] = _cargo_payment_rates_frac[9];
+		return true;
+	}
+
 	if (!LoadChunk(ls, NULL, cargo_payment_rate_chunk)) return false;
 
+	if (_savegame_type == SGT_TTO) {
+		/* SVXConverter about cargo payment rates correction:
+		* "increase them to compensate for the faster time advance in TTD compared to TTO
+		* which otherwise would cause much less income while the annual running costs of
+		* the vehicles stay the same" */
+
+		Money m = ((((Money)_old_price) << 16) + _old_price_frac) * 124 / 74;
+
+		_old_price = m >> 16;
+		_old_price_frac = GB(m, 0, 16);
+	}
+
 	_cargo_payment_rates[num] = -_old_price;
 	_cargo_payment_rates_frac[num] = _old_price_frac;
 
 	return true;
 }
 
-static uint   _current_station_id;
+VehicleID _current_station_id;
 static uint16 _waiting_acceptance;
 static uint8  _cargo_source;
 static uint8  _cargo_days;
@@ -392,10 +697,13 @@ static const OldChunks goods_chunk[] = {
 
 static bool LoadOldGood(LoadgameState *ls, int num)
 {
+	/* for TTO games, 12th (num == 11) goods entry is created in the Station constructor */
+	if (_savegame_type == SGT_TTO && num == 11) return true;
+
 	Station *st = GetStation(_current_station_id);
 	GoodsEntry *ge = &st->goods[num];
-	bool ret = LoadChunk(ls, ge, goods_chunk);
-	if (!ret) return false;
+
+	if (!LoadChunk(ls, ge, goods_chunk)) return false;
 
 	SB(ge->acceptance_pickup, GoodsEntry::ACCEPTANCE, 1, HasBit(_waiting_acceptance, 15));
 	SB(ge->acceptance_pickup, GoodsEntry::PICKUP, 1, _cargo_source != 0xFF);
@@ -406,7 +714,8 @@ static bool LoadOldGood(LoadgameState *ls, int num)
 		cp->days_in_transit = _cargo_days;
 		ge->cargo.Append(cp);
 	}
-	return ret;
+
+	return true;
 }
 
 static const OldChunks station_chunk[] = {
@@ -435,30 +744,44 @@ static const OldChunks station_chunk[] = {
 	OCL_SVAR(  OC_UINT8, Station, delete_ctr ),
 	OCL_SVAR(  OC_UINT8, Station, owner ),
 	OCL_SVAR(  OC_UINT8, Station, facilities ),
-	OCL_SVAR(  OC_UINT8, Station, airport_type ),
-	/* Bus/truck status, no longer in use
-	 * Blocked months
-	 * Unknown
-	 */
-	OCL_NULL( 4 ),
-	OCL_SVAR( OC_FILE_U16 | OC_VAR_U32, Station, airport_flags ),
-	OCL_NULL( 2 ),         ///< last_vehicle. now last_vehicle_type
-
-	OCL_NULL( 4 ),         ///< Junk at end of chunk
+	OCL_SVAR( OC_TTD | OC_UINT8, Station, airport_type ),
+	OCL_SVAR( OC_TTO | OC_FILE_U16 | OC_VAR_U32, Station, airport_flags ),
+	OCL_NULL( 3 ),          ///< bus/truck status, blocked months, no longer in use
+	OCL_CNULL( OC_TTD, 1 ), ///< unknown
+	OCL_SVAR( OC_TTD | OC_FILE_U16 | OC_VAR_U32, Station, airport_flags ),
+	OCL_CNULL( OC_TTD, 2 ), ///< last_vehicle. now last_vehicle_type
+	OCL_CNULL( OC_TTD, 4 ), ///< junk at end of chunk
 
 	OCL_END()
 };
+
 static bool LoadOldStation(LoadgameState *ls, int num)
 {
 	Station *st = new (num) Station();
 	_current_station_id = num;
 
-	if (!LoadChunk(ls, st, station_chunk))
-		return false;
+	if (!LoadChunk(ls, st, station_chunk)) return false;
 
 	if (st->xy != 0) {
-		st->town    = GetTown(REMAP_TOWN_IDX(_old_town_index));
-		st->string_id = RemapOldStringID(_old_string_id);
+		st->town = GetTown(RemapTownIndex(_old_town_index));
+
+		if (_savegame_type == SGT_TTO) {
+			if (IsInsideBS(_old_string_id, 0x180F, 32)) {
+				st->string_id = STR_SV_STNAME + (_old_string_id - 0x180F); // automatic name
+			} else {
+				st->string_id = _old_string_id + 0x2800; // custom name
+			}
+
+			if (HasBit(st->airport_flags, 8)) {
+				st->airport_type = 1; // large airport
+			} else if (HasBit(st->airport_flags, 6)) {
+				st->airport_type = 3; // oil rig
+			} else {
+				st->airport_type = 0; // small airport
+			}
+		} else {
+			st->string_id = RemapOldStringID(_old_string_id);
+		}
 	} else {
 		st->xy = INVALID_TILE;
 	}
@@ -473,8 +796,10 @@ static const OldChunks industry_chunk[] = {
 	OCL_SVAR(  OC_UINT8, Industry, height ),
 	OCL_NULL( 2 ),  ///< used to be industry's produced_cargo
 
-	OCL_SVAR( OC_UINT16, Industry, produced_cargo_waiting[0] ),
-	OCL_SVAR( OC_UINT16, Industry, produced_cargo_waiting[1] ),
+	OCL_SVAR( OC_TTD | OC_UINT16, Industry, produced_cargo_waiting[0] ),
+	OCL_SVAR( OC_TTD | OC_UINT16, Industry, produced_cargo_waiting[1] ),
+	OCL_SVAR( OC_TTO | OC_FILE_U8 | OC_VAR_U16, Industry, produced_cargo_waiting[0] ),
+	OCL_SVAR( OC_TTO | OC_FILE_U8 | OC_VAR_U16, Industry, produced_cargo_waiting[1] ),
 
 	OCL_SVAR(  OC_UINT8, Industry, production_rate[0] ),
 	OCL_SVAR(  OC_UINT8, Industry, production_rate[1] ),
@@ -497,13 +822,14 @@ static const OldChunks industry_chunk[] = {
 	OCL_SVAR( OC_UINT16, Industry, last_month_transported[1] ),
 
 	OCL_SVAR(  OC_UINT8, Industry, type ),
+	OCL_SVAR( OC_TTO | OC_FILE_U8 | OC_VAR_U16, Industry, counter ),
 	OCL_SVAR(  OC_UINT8, Industry, owner ),
 	OCL_SVAR(  OC_UINT8, Industry, random_color ),
-	OCL_SVAR( OC_FILE_U8 | OC_VAR_I32, Industry, last_prod_year ),
-	OCL_SVAR( OC_UINT16, Industry, counter ),
-	OCL_SVAR(  OC_UINT8, Industry, was_cargo_delivered ),
+	OCL_SVAR( OC_TTD | OC_FILE_U8 | OC_VAR_I32, Industry, last_prod_year ),
+	OCL_SVAR( OC_TTD | OC_UINT16, Industry, counter ),
+	OCL_SVAR( OC_TTD | OC_UINT8, Industry, was_cargo_delivered ),
 
-	OCL_NULL( 9 ), ///< Random junk at the end of this chunk
+	OCL_CNULL( OC_TTD, 9 ), ///< Random junk at the end of this chunk
 
 	OCL_END()
 };
@@ -514,7 +840,19 @@ static bool LoadOldIndustry(LoadgameState *ls, int num)
 	if (!LoadChunk(ls, i, industry_chunk)) return false;
 
 	if (i->xy != 0) {
-		i->town = GetTown(REMAP_TOWN_IDX(_old_town_index));
+		i->town = GetTown(RemapTownIndex(_old_town_index));
+
+		if (_savegame_type == SGT_TTO) {
+			if (i->type > 0x06) i->type++; // Printing Works were added
+			if (i->type == 0x0A) i->type = 0x12; // Iron Ore Mine has different ID
+
+			YearMonthDay ymd;
+			ConvertDateToYMD(_date, &ymd);
+			i->last_prod_year = ymd.year;
+
+			i->random_color = RemapTTOColour(i->random_color);
+		}
+
 		IncIndustryTypeCount(i->type);
 	} else {
 		i->xy = INVALID_TILE;
@@ -523,7 +861,7 @@ static bool LoadOldIndustry(LoadgameState *ls, int num)
 	return true;
 }
 
-static CompanyID _current_company_id;
+CompanyID _current_company_id;
 static int32 _old_yearly;
 
 static const OldChunks _company_yearly_chunk[] = {
@@ -531,13 +869,16 @@ static const OldChunks _company_yearly_chunk[] = {
 	OCL_END()
 };
 
-static bool OldCompanyYearly(LoadgameState *ls, int num)
+static bool LoadOldCompanyYearly(LoadgameState *ls, int num)
 {
-	int i;
 	Company *c = GetCompany(_current_company_id);
 
-	for (i = 0; i < 13; i++) {
-		if (!LoadChunk(ls, NULL, _company_yearly_chunk)) return false;
+	for (uint i = 0; i < 13; i++) {
+		if (_savegame_type == SGT_TTO && i == 6) {
+			_old_yearly = 0; // property maintenance
+		} else {
+			if (!LoadChunk(ls, NULL, _company_yearly_chunk)) return false;
+		}
 
 		c->yearly_expenses[num][i] = _old_yearly;
 	}
@@ -550,14 +891,13 @@ static const OldChunks _company_economy_chunk[] = {
 	OCL_SVAR( OC_FILE_I32 | OC_VAR_I64, CompanyEconomyEntry, expenses ),
 	OCL_SVAR( OC_INT32,                 CompanyEconomyEntry, delivered_cargo ),
 	OCL_SVAR( OC_INT32,                 CompanyEconomyEntry, performance_history ),
-	OCL_SVAR( OC_FILE_I32 | OC_VAR_I64, CompanyEconomyEntry, company_value ),
+	OCL_SVAR( OC_TTD | OC_FILE_I32 | OC_VAR_I64, CompanyEconomyEntry, company_value ),
 
 	OCL_END()
 };
 
-static bool OldCompanyEconomy(LoadgameState *ls, int num)
+static bool LoadOldCompanyEconomy(LoadgameState *ls, int num)
 {
-	int i;
 	Company *c = GetCompany(_current_company_id);
 
 	if (!LoadChunk(ls, &c->cur_economy, _company_economy_chunk)) return false;
@@ -566,7 +906,7 @@ static bool OldCompanyEconomy(LoadgameState *ls, int num)
 	c->cur_economy.income   = -c->cur_economy.income;
 	c->cur_economy.expenses = -c->cur_economy.expenses;
 
-	for (i = 0; i < 24; i++) {
+	for (uint i = 0; i < 24; i++) {
 		if (!LoadChunk(ls, &c->old_economy[i], _company_economy_chunk)) return false;
 
 		c->old_economy[i].income   = -c->old_economy[i].income;
@@ -593,10 +933,11 @@ static const OldChunks _company_chunk[] = {
 	OCL_SVAR( OC_FILE_U32 | OC_VAR_I64, Company, bankrupt_value ),
 	OCL_SVAR( OC_UINT16, Company, bankrupt_timeout ),
 
-	OCL_SVAR( OC_UINT32, Company, cargo_types ),
+	OCL_SVAR( OC_TTD | OC_UINT32, Company, cargo_types ),
+	OCL_SVAR( OC_TTO | OC_FILE_U16 | OC_VAR_U32, Company, cargo_types ),
 
-	OCL_CHUNK( 3, OldCompanyYearly ),
-	OCL_CHUNK( 1, OldCompanyEconomy ),
+	OCL_CHUNK( 3, LoadOldCompanyYearly ),
+	OCL_CHUNK( 1, LoadOldCompanyEconomy ),
 
 	OCL_SVAR( OC_FILE_U16 | OC_VAR_I32, Company, inaugurated_year),
 	OCL_SVAR(                  OC_TILE, Company, last_build_coordinate ),
@@ -605,15 +946,15 @@ static const OldChunks _company_chunk[] = {
 	OCL_NULL( 230 ),         // Old AI
 
 	OCL_SVAR(  OC_UINT8, Company, block_preview ),
-	OCL_NULL( 1 ),           // Old AI
-	OCL_SVAR(  OC_UINT8, Company, avail_railtypes ),
+	OCL_CNULL( OC_TTD, 1 ),           // Old AI
+	OCL_SVAR( OC_TTD | OC_UINT8, Company, avail_railtypes ),
 	OCL_SVAR(   OC_TILE, Company, location_of_HQ ),
-	OCL_SVAR(  OC_UINT8, Company, share_owners[0] ),
-	OCL_SVAR(  OC_UINT8, Company, share_owners[1] ),
-	OCL_SVAR(  OC_UINT8, Company, share_owners[2] ),
-	OCL_SVAR(  OC_UINT8, Company, share_owners[3] ),
+	OCL_SVAR( OC_TTD | OC_UINT8, Company, share_owners[0] ),
+	OCL_SVAR( OC_TTD | OC_UINT8, Company, share_owners[1] ),
+	OCL_SVAR( OC_TTD | OC_UINT8, Company, share_owners[2] ),
+	OCL_SVAR( OC_TTD | OC_UINT8, Company, share_owners[3] ),
 
-	OCL_NULL( 8 ), ///< junk at end of chunk
+	OCL_CNULL( OC_TTD, 8 ), ///< junk at end of chunk
 
 	OCL_END()
 };
@@ -631,25 +972,55 @@ static bool LoadOldCompany(LoadgameState *ls, int num)
 		return true;
 	}
 
-	c->name_1 = RemapOldStringID(_old_string_id);
-	c->president_name_1 = RemapOldStringID(_old_string_id_2);
+	if (_savegame_type == SGT_TTO) {
+		/* adjust manager's face */
+		if (HasBit(c->face, 27) && GB(c->face, 26, 1) == GB(c->face, 19, 1)) {
+			/* if face would be black in TTD, adjust tie color and thereby face color */
+			ClrBit(c->face, 27);
+		}
 
-	if (num == 0) {
-		/* If the first company has no name, make sure we call it UNNAMED */
-		if (c->name_1 == 0)
-			c->name_1 = STR_SV_UNNAMED;
+		/* Company name */
+		if (_old_string_id == 0 || _old_string_id == 0x4C00) {
+			_old_string_id = STR_SV_UNNAMED; // "Unnamed"
+		} else if (GB(_old_string_id, 8, 8) == 0x52) {
+			_old_string_id += 0x2A00; // Custom name
+		} else {
+			_old_string_id = RemapOldStringID(_old_string_id += 0x240D); // Automatic name
+		}
+		c->name_1 = _old_string_id;
+
+		/* Manager name */
+		switch (_old_string_id_2) {
+			case 0x4CDA: _old_string_id_2 = SPECSTR_PRESIDENT_NAME;    break; // automatic name
+			case 0x0006: _old_string_id_2 = STR_SV_EMPTY;              break; // empty name
+			default:     _old_string_id_2 = _old_string_id_2 + 0x2A00; break; // custom name
+		}
+		c->president_name_1 = _old_string_id_2;
+
+		c->colour = RemapTTOColour(c->colour);
+
+		if (num != 0) c->is_ai = true;
 	} else {
-		/* Beside some multiplayer maps (1 on 1), which we don't official support,
-		 * all other companys are an AI.. mark them as such */
-		c->is_ai = true;
-	}
+		c->name_1 = RemapOldStringID(_old_string_id);
+		c->president_name_1 = RemapOldStringID(_old_string_id_2);
+
+		if (num == 0) {
+			/* If the first company has no name, make sure we call it UNNAMED */
+			if (c->name_1 == 0)
+				c->name_1 = STR_SV_UNNAMED;
+		} else {
+			/* Beside some multiplayer maps (1 on 1), which we don't official support,
+			* all other companys are an AI.. mark them as such */
+			c->is_ai = true;
+		}
 
-	/* Sometimes it is better to not ask.. in old scenarios, the money
-	 * was always 893288 pounds. In the newer versions this is correct,
-	 * but correct for those oldies
-	 * Ps: this also means that if you had exact 893288 pounds, you will go back
-	 * to 100000.. this is a very VERY small chance ;) */
-	if (c->money == 893288) c->money = c->current_loan = 100000;
+		/* Sometimes it is better to not ask.. in old scenarios, the money
+		* was always 893288 pounds. In the newer versions this is correct,
+		* but correct for those oldies
+		* Ps: this also means that if you had exact 893288 pounds, you will go back
+		* to 100000.. this is a very VERY small chance ;) */
+		if (c->money == 893288) c->money = c->current_loan = 100000;
+	}
 
 	_company_colours[num] = c->colour;
 	c->inaugurated_year -= ORIGINAL_BASE_YEAR;
@@ -659,7 +1030,7 @@ static bool LoadOldCompany(LoadgameState *ls, int num)
 
 static uint32 _old_order_ptr;
 static uint16 _old_next_ptr;
-static uint32 _current_vehicle_id;
+VehicleID _current_vehicle_id;
 
 static const OldChunks vehicle_train_chunk[] = {
 	OCL_SVAR(  OC_UINT8, VehicleRail, track ),
@@ -773,8 +1144,9 @@ static const OldChunks vehicle_chunk[] = {
 	OCL_SVAR( OC_FILE_U16 | OC_VAR_U32, Vehicle, date_of_last_service ),
 	OCL_SVAR( OC_UINT16, Vehicle, service_interval ),
 	OCL_SVAR( OC_FILE_U8 | OC_VAR_U16, Vehicle, last_station_visited ),
-	OCL_SVAR(  OC_UINT8, Vehicle, tick_counter ),
-	OCL_SVAR( OC_UINT16, Vehicle, max_speed ),
+	OCL_SVAR( OC_TTD | OC_UINT8, Vehicle, tick_counter ),
+	OCL_SVAR( OC_TTD | OC_UINT16, Vehicle, max_speed ),
+	OCL_SVAR( OC_TTO | OC_FILE_U8 | OC_VAR_U16, Vehicle, max_speed ),
 
 	OCL_SVAR( OC_FILE_U16 | OC_VAR_I32, Vehicle, x_pos ),
 	OCL_SVAR( OC_FILE_U16 | OC_VAR_I32, Vehicle, y_pos ),
@@ -791,23 +1163,29 @@ static const OldChunks vehicle_chunk[] = {
 	OCL_NULL( 8 ),        ///< Vehicle sprite box, calculated automatically
 
 	OCL_SVAR( OC_FILE_U16 | OC_VAR_U8, Vehicle, vehstatus ),
-	OCL_SVAR( OC_UINT16, Vehicle, cur_speed ),
+	OCL_SVAR( OC_TTD | OC_UINT16, Vehicle, cur_speed ),
+	OCL_SVAR( OC_TTO | OC_FILE_U8 | OC_VAR_U16, Vehicle, cur_speed ),
 	OCL_SVAR(  OC_UINT8, Vehicle, subspeed ),
 	OCL_SVAR(  OC_UINT8, Vehicle, acceleration ),
 	OCL_SVAR(  OC_UINT8, Vehicle, progress ),
 
 	OCL_SVAR(  OC_UINT8, Vehicle, cargo_type ),
-	OCL_SVAR( OC_UINT16, Vehicle, cargo_cap ),
-	OCL_VAR ( OC_UINT16, 1,       &_cargo_count ),
+	OCL_SVAR( OC_TTD | OC_UINT16, Vehicle, cargo_cap ),
+	OCL_SVAR( OC_TTO | OC_FILE_U8 | OC_VAR_U16, Vehicle, cargo_cap ),
+	OCL_VAR ( OC_TTD | OC_UINT16, 1, &_cargo_count ),
+	OCL_VAR ( OC_TTO | OC_FILE_U8 | OC_VAR_U16, 1, &_cargo_count ),
 	OCL_VAR (  OC_UINT8, 1,       &_cargo_source ),
 	OCL_VAR (  OC_UINT8, 1,       &_cargo_days ),
 
+	OCL_SVAR( OC_TTO | OC_UINT8, Vehicle, tick_counter ),
+
 	OCL_SVAR( OC_FILE_U16 | OC_VAR_U32, Vehicle, age ),
 	OCL_SVAR( OC_FILE_U16 | OC_VAR_U32, Vehicle, max_age ),
 	OCL_SVAR( OC_FILE_U8 | OC_VAR_I32, Vehicle, build_year ),
 	OCL_SVAR( OC_FILE_U8 | OC_VAR_U16, Vehicle, unitnumber ),
 
-	OCL_SVAR( OC_UINT16, Vehicle, engine_type ),
+	OCL_SVAR( OC_TTD | OC_UINT16, Vehicle, engine_type ),
+	OCL_SVAR( OC_TTO | OC_FILE_U8 | OC_VAR_U16, Vehicle, engine_type ),
 
 	OCL_SVAR(  OC_UINT8, Vehicle, spritenum ),
 	OCL_SVAR(  OC_UINT8, Vehicle, day_counter ),
@@ -817,6 +1195,8 @@ static const OldChunks vehicle_chunk[] = {
 	OCL_SVAR(  OC_UINT8, Vehicle, breakdown_delay ),
 	OCL_SVAR(  OC_UINT8, Vehicle, breakdown_chance ),
 
+	OCL_CNULL( OC_TTO, 1 ),
+
 	OCL_SVAR( OC_UINT16, Vehicle, reliability ),
 	OCL_SVAR( OC_UINT16, Vehicle, reliability_spd_dec ),
 
@@ -831,7 +1211,8 @@ static const OldChunks vehicle_chunk[] = {
 
 	OCL_CHUNK( 1, LoadOldVehicleUnion ),
 
-	OCL_NULL( 20 ), ///< Junk at end of struct (TTDPatch has some data in it)
+	OCL_CNULL( OC_TTO, 24 ), ///< junk
+	OCL_CNULL( OC_TTD, 20 ), ///< junk at end of struct (TTDPatch has some data in it)
 
 	OCL_END()
 };
@@ -844,40 +1225,116 @@ bool LoadOldVehicle(LoadgameState *ls, int num)
 	for (uint i = 0; i < _old_vehicle_multiplier; i++) {
 		_current_vehicle_id = num * _old_vehicle_multiplier + i;
 
-		/* Read the vehicle type and allocate the right vehicle */
 		Vehicle *v;
-		switch (ReadByte(ls)) {
-			default: NOT_REACHED();
-			case 0x00 /*VEH_INVALID */: v = new (_current_vehicle_id) InvalidVehicle();  break;
-			case 0x10 /*VEH_TRAIN   */: v = new (_current_vehicle_id) Train();           break;
-			case 0x11 /*VEH_ROAD    */: v = new (_current_vehicle_id) RoadVehicle();     break;
-			case 0x12 /*VEH_SHIP    */: v = new (_current_vehicle_id) Ship();            break;
-			case 0x13 /*VEH_AIRCRAFT*/: v = new (_current_vehicle_id) Aircraft();        break;
-			case 0x14 /*VEH_EFFECT  */: v = new (_current_vehicle_id) EffectVehicle();   break;
-			case 0x15 /*VEH_DISASTER*/: v = new (_current_vehicle_id) DisasterVehicle(); break;
-		}
-		if (!LoadChunk(ls, v, vehicle_chunk)) return false;
 
-		/* This should be consistent, else we have a big problem... */
-		if (v->index != _current_vehicle_id) {
-			DEBUG(oldloader, 0, "Loading failed - vehicle-array is invalid");
-			return false;
+		if (_savegame_type == SGT_TTO) {
+			uint type = ReadByte(ls);
+			switch (type) {
+				default: return false;
+				case 0x00 /*VEH_INVALID */: v = new (_current_vehicle_id) InvalidVehicle();  break;
+				case 0x25 /* MONORAIL   */:
+				case 0x20 /*VEH_TRAIN   */: v = new (_current_vehicle_id) Train();           break;
+				case 0x21 /*VEH_ROAD    */: v = new (_current_vehicle_id) RoadVehicle();     break;
+				case 0x22 /*VEH_SHIP    */: v = new (_current_vehicle_id) Ship();            break;
+				case 0x23 /*VEH_AIRCRAFT*/: v = new (_current_vehicle_id) Aircraft();        break;
+				case 0x24 /*VEH_EFFECT  */: v = new (_current_vehicle_id) EffectVehicle();   break;
+				case 0x26 /*VEH_DISASTER*/: v = new (_current_vehicle_id) DisasterVehicle(); break;
+			}
+
+			if (!LoadChunk(ls, v, vehicle_chunk)) return false;
+
+			SpriteID sprite = v->cur_image;
+			/* no need to override other sprites */
+			if (IsInsideMM(sprite, 1460, 1465)) {
+				sprite += 580; // aircraft smoke puff
+			} else if (IsInsideMM(sprite, 2096, 2115)) {
+				sprite += 977; // special effects part 1
+			} else if (IsInsideMM(sprite, 2396, 2436)) {
+				sprite += 1305; // special effects part 2
+			} else if (IsInsideMM(sprite, 2516, 2539)) {
+				sprite += 1385; // rotor or disaster-related vehicles
+			}
+			v->cur_image = sprite;
+
+			switch (v->type) {
+				case VEH_TRAIN: {
+					static const byte spriteset_rail[] = {
+						0,   2,   4,   4,   8,  10,  12,  14,  16,  18,  20,  22,  40,  42,  44,  46,
+						48,  52,  54,  66,  68,  70,  72,  74,  76,  78,  80,  82,  84,  86, 120, 122,
+						124, 126, 128, 130, 132, 134, 136, 138, 140
+					};
+					if (v->spritenum / 2 >= lengthof(spriteset_rail)) return false;
+					v->spritenum = spriteset_rail[v->spritenum / 2]; // adjust railway sprite set offset
+					v->u.rail.railtype = type == 0x25 ? 1 : 0; // monorail / rail
+					break;
+				}
+
+				case VEH_ROAD:
+					if (v->spritenum >= 22) v->spritenum += 12;
+					break;
+
+				case VEH_SHIP:
+					v->spritenum += 2;
+
+					switch (v->spritenum) {
+						case 2: // oil tanker && cargo type != oil
+							if (v->cargo_type != CT_OIL) v->spritenum = 0; // make it a coal/goods ship
+							break;
+						case 4: // passenger ship && cargo type == mail
+							if (v->cargo_type == CT_MAIL) v->spritenum = 0; // make it a mail ship
+							break;
+						default:
+							break;
+					}
+					break;
+
+				default:
+					break;
+			}
+
+			switch (_old_string_id) {
+				case 0x0000: break; // empty (invalid vehicles)
+				case 0x0006: _old_string_id  = STR_SV_EMPTY;         break; // empty (special vehicles)
+				case 0x8495: _old_string_id  = STR_SV_TRAIN_NAME;    break; // "Train X"
+				case 0x8842: _old_string_id  = STR_SV_ROADVEH_NAME;  break; // "Road Vehicle X"
+				case 0x8C3B: _old_string_id  = STR_SV_SHIP_NAME;     break; // "Ship X"
+				case 0x9047: _old_string_id  = STR_SV_AIRCRAFT_NAME; break; // "Aircraft X"
+				default:     _old_string_id += 0x2A00;               break; // custom name
+			}
+
+			_old_vehicle_names[_current_vehicle_id] = _old_string_id;
+		} else {
+			/* Read the vehicle type and allocate the right vehicle */
+			switch (ReadByte(ls)) {
+				default: NOT_REACHED();
+				case 0x00 /*VEH_INVALID */: v = new (_current_vehicle_id) InvalidVehicle();  break;
+				case 0x10 /*VEH_TRAIN   */: v = new (_current_vehicle_id) Train();           break;
+				case 0x11 /*VEH_ROAD    */: v = new (_current_vehicle_id) RoadVehicle();     break;
+				case 0x12 /*VEH_SHIP    */: v = new (_current_vehicle_id) Ship();            break;
+				case 0x13 /*VEH_AIRCRAFT*/: v = new (_current_vehicle_id) Aircraft();        break;
+				case 0x14 /*VEH_EFFECT  */: v = new (_current_vehicle_id) EffectVehicle();   break;
+				case 0x15 /*VEH_DISASTER*/: v = new (_current_vehicle_id) DisasterVehicle(); break;
+			}
+			if (!LoadChunk(ls, v, vehicle_chunk)) return false;
+
+			_old_vehicle_names[_current_vehicle_id] = RemapOldStringID(_old_string_id);
+
+			/* This should be consistent, else we have a big problem... */
+			if (v->index != _current_vehicle_id) {
+				DEBUG(oldloader, 0, "Loading failed - vehicle-array is invalid");
+				return false;
+			}
 		}
 
 		if (_old_order_ptr != 0 && _old_order_ptr != 0xFFFFFFFF) {
-			uint old_id = REMAP_ORDER_IDX(_old_order_ptr);
-			/* There is a maximum of 5000 orders in old savegames, so *if*
-			 * we go over that limit something is very wrong. In that case
-			 * we just assume there are no orders for the vehicle.
-			 */
-			if (old_id < 5000) v->orders.old = GetOrder(old_id);
+			uint max = _savegame_type == SGT_TTO ? 3000 : 5000;
+			uint old_id = RemapOrderIndex(_old_order_ptr);
+			if (old_id < max) v->orders.old = GetOrder(old_id); // don't accept orders > max number of orders
 		}
 		v->current_order.AssignOrder(UnpackOldOrder(_old_order));
 
 		if (_old_next_ptr != 0xFFFF) v->next = GetVehiclePoolSize() <= _old_next_ptr ? new (_old_next_ptr) InvalidVehicle() : GetVehicle(_old_next_ptr);
 
-		_old_vehicle_names[_current_vehicle_id] = RemapOldStringID(_old_string_id);
-
 		if (_cargo_count != 0) {
 			CargoPacket *cp = new CargoPacket((_cargo_source == 0xFF) ? INVALID_STATION : _cargo_source, _cargo_count);
 			cp->days_in_transit = _cargo_days;
@@ -905,8 +1362,11 @@ static bool LoadOldSign(LoadgameState *ls, int num)
 	if (!LoadChunk(ls, si, sign_chunk)) return false;
 
 	if (_old_string_id != 0) {
-		_old_string_id = RemapOldStringID(_old_string_id);
-		si->name = CopyFromOldName(_old_string_id);
+		if (_savegame_type == SGT_TTO) {
+			if (_old_string_id != 0x140A) si->name = CopyFromOldName(_old_string_id + 0x2A00);
+		} else {
+			si->name = CopyFromOldName(RemapOldStringID(_old_string_id));
+		}
 		si->owner = OWNER_NONE;
 	}
 
@@ -931,14 +1391,14 @@ static const OldChunks engine_chunk[] = {
 	OCL_SVAR(  OC_UINT8, Engine, preview_company_rank ),
 	OCL_SVAR(  OC_UINT8, Engine, preview_wait ),
 
-	OCL_NULL( 2 ), ///< railtype + junk
+	OCL_CNULL( OC_TTD, 2 ), ///< railtype + junk
 
 	OCL_END()
 };
 
 static bool LoadOldEngine(LoadgameState *ls, int num)
 {
-	Engine *e = GetTempDataEngine(num);
+	Engine *e = _savegame_type == SGT_TTO ? &_old_engines[num] : GetTempDataEngine(num);
 	return LoadChunk(ls, e, engine_chunk);
 }
 
@@ -958,7 +1418,7 @@ static const OldChunks subsidy_chunk[] = {
 	OCL_END()
 };
 
-static inline bool LoadOldSubsidy(LoadgameState *ls, int num)
+static bool LoadOldSubsidy(LoadgameState *ls, int num)
 {
 	return LoadChunk(ls, &_subsidies[num], subsidy_chunk);
 }
@@ -984,7 +1444,7 @@ static const OldChunks game_difficulty_chunk[] = {
 	OCL_END()
 };
 
-static inline bool LoadOldGameDifficulty(LoadgameState *ls, int num)
+static bool LoadOldGameDifficulty(LoadgameState *ls, int num)
 {
 	bool ret = LoadChunk(ls, &_settings_game.difficulty, game_difficulty_chunk);
 	_settings_game.difficulty.max_loan *= 1000;
@@ -994,24 +1454,30 @@ static inline bool LoadOldGameDifficulty(LoadgameState *ls, int num)
 
 static bool LoadOldMapPart1(LoadgameState *ls, int num)
 {
-	uint i;
+	if (_savegame_type == SGT_TTO) {
+		MemSetT(_m, 0, OLD_MAP_SIZE);
+		MemSetT(_me, 0, OLD_MAP_SIZE);
+	}
 
-	for (i = 0; i < OLD_MAP_SIZE; i++) {
+	for (uint i = 0; i < OLD_MAP_SIZE; i++) {
 		_m[i].m1 = ReadByte(ls);
 	}
-	for (i = 0; i < OLD_MAP_SIZE; i++) {
+	for (uint i = 0; i < OLD_MAP_SIZE; i++) {
 		_m[i].m2 = ReadByte(ls);
 	}
-	for (i = 0; i < OLD_MAP_SIZE; i++) {
-		_old_map3[i * 2] = ReadByte(ls);
-		_old_map3[i * 2 + 1] = ReadByte(ls);
-	}
-	for (i = 0; i < OLD_MAP_SIZE / 4; i++) {
-		byte b = ReadByte(ls);
-		_m[i * 4 + 0].m6 = GB(b, 0, 2);
-		_m[i * 4 + 1].m6 = GB(b, 2, 2);
-		_m[i * 4 + 2].m6 = GB(b, 4, 2);
-		_m[i * 4 + 3].m6 = GB(b, 6, 2);
+
+	if (_savegame_type != SGT_TTO) {
+		for (uint i = 0; i < OLD_MAP_SIZE; i++) {
+			_old_map3[i * 2] = ReadByte(ls);
+			_old_map3[i * 2 + 1] = ReadByte(ls);
+		}
+		for (uint i = 0; i < OLD_MAP_SIZE / 4; i++) {
+			byte b = ReadByte(ls);
+			_m[i * 4 + 0].m6 = GB(b, 0, 2);
+			_m[i * 4 + 1].m6 = GB(b, 2, 2);
+			_m[i * 4 + 2].m6 = GB(b, 4, 2);
+			_m[i * 4 + 3].m6 = GB(b, 6, 2);
+		}
 	}
 
 	return !ls->failed;
@@ -1090,23 +1556,38 @@ static bool LoadTTDPatchExtraChunks(LoadgameState *ls, int num)
 extern TileIndex _cur_tileloop_tile;
 static uint32 _old_cur_town_ctr;
 static const OldChunks main_chunk[] = {
-	OCL_ASSERT( 0 ),
+	OCL_ASSERT( OC_TTD, 0 ),
+	OCL_ASSERT( OC_TTO, 0 ),
 	OCL_VAR ( OC_FILE_U16 | OC_VAR_U32, 1, &_date ),
 	OCL_VAR ( OC_UINT16,   1, &_date_fract ),
 	OCL_NULL( 600 ),            ///< TextEffects
 	OCL_VAR ( OC_UINT32,   2, &_random.state ),
 
-	OCL_ASSERT( 0x264 ),
-	OCL_CHUNK(  70, LoadOldTown ),
-	OCL_ASSERT( 0x1C18 ),
-	OCL_CHUNK(5000, LoadOldOrder ),
-	OCL_ASSERT( 0x4328 ),
+	OCL_ASSERT( OC_TTD, 0x264 ),
+	OCL_ASSERT( OC_TTO, 0x264 ),
+
+	OCL_CCHUNK( OC_TTD, 70, LoadOldTown ),
+	OCL_CCHUNK( OC_TTO, 80, LoadOldTown ),
+
+	OCL_ASSERT( OC_TTD, 0x1C18 ),
+	OCL_ASSERT( OC_TTO, 0x1AC4 ),
+
+	OCL_CCHUNK( OC_TTD, 5000, LoadOldOrder ),
+	OCL_CCHUNK( OC_TTO, 3000, LoadOldOrder ),
+
+	OCL_ASSERT( OC_TTD, 0x4328 ),
+	OCL_ASSERT( OC_TTO, 0x3234 ),
 
 	OCL_CHUNK( 1, LoadOldAnimTileList ),
 	OCL_NULL( 4 ),              ///< old end-of-order-list-pointer, no longer in use
 
-	OCL_CHUNK( 255, LoadOldDepot ),
-	OCL_ASSERT( 0x4B26 ),
+	OCL_ASSERT( OC_TTO, 0x3438 ),
+
+	OCL_CCHUNK( OC_TTD, 255, LoadOldDepot ),
+	OCL_CCHUNK( OC_TTO, 252, LoadOldDepot ),
+
+	OCL_ASSERT( OC_TTD, 0x4B26 ),
+	OCL_ASSERT( OC_TTO, 0x3A20 ),
 
 	OCL_VAR ( OC_UINT32,   1, &_old_cur_town_ctr ),
 	OCL_NULL( 2 ),              ///< timer_counter, no longer in use
@@ -1116,37 +1597,69 @@ static const OldChunks main_chunk[] = {
 	OCL_VAR ( OC_UINT16,   1, &_tick_counter ),
 	OCL_VAR (   OC_TILE,   1, &_cur_tileloop_tile ),
 
+	OCL_ASSERT( OC_TTO, 0x3A2E ),
+
 	OCL_CHUNK( 49, LoadOldPrice ),
+
+	OCL_ASSERT( OC_TTO, 0x3B4E ),
+
 	OCL_CHUNK( 12, LoadOldCargoPaymentRate ),
 
-	OCL_ASSERT( 0x4CBA ),
+	OCL_ASSERT( OC_TTD, 0x4CBA ),
+	OCL_ASSERT( OC_TTO, 0x3BA6 ),
 
 	OCL_CHUNK( 1, LoadOldMapPart1 ),
 
-	OCL_ASSERT( 0x48CBA ),
+	OCL_ASSERT( OC_TTD, 0x48CBA ),
+	OCL_ASSERT( OC_TTO, 0x23BA6 ),
+
+	OCL_CCHUNK( OC_TTD, 250, LoadOldStation ),
+	OCL_CCHUNK( OC_TTO, 200, LoadOldStation ),
+
+	OCL_ASSERT( OC_TTO, 0x29E16 ),
+
+	OCL_CCHUNK( OC_TTD, 90, LoadOldIndustry ),
+	OCL_CCHUNK( OC_TTO, 100, LoadOldIndustry ),
+
+	OCL_ASSERT( OC_TTO, 0x2ADB6 ),
 
-	OCL_CHUNK(250, LoadOldStation ),
-	OCL_CHUNK( 90, LoadOldIndustry ),
 	OCL_CHUNK(  8, LoadOldCompany ),
 
-	OCL_ASSERT( 0x547F2 ),
+	OCL_ASSERT( OC_TTD, 0x547F2 ),
+	OCL_ASSERT( OC_TTO, 0x2C746 ),
+
+	OCL_CCHUNK( OC_TTD, 850, LoadOldVehicle ),
+	OCL_CCHUNK( OC_TTO, 800, LoadOldVehicle ),
 
-	OCL_CHUNK( 850, LoadOldVehicle ),
+	OCL_ASSERT( OC_TTD, 0x6F0F2 ),
+	OCL_ASSERT( OC_TTO, 0x45746 ),
 
-	OCL_ASSERT( 0x6F0F2 ),
+	OCL_VAR ( OC_TTD | OC_UINT8 | OC_DEREFERENCE_POINTER, 32 * 500, &_old_name_array ),
+	OCL_VAR ( OC_TTO | OC_UINT8 | OC_DEREFERENCE_POINTER, 24 * 200, &_old_name_array ),
 
-	OCL_VAR (  OC_UINT8 | OC_DEREFERENCE_POINTER, 32 * 500, &_old_name_array ),
+	OCL_ASSERT( OC_TTO, 0x46A06 ),
 
 	OCL_NULL( 0x2000 ),            ///< Old hash-table, no longer in use
 
 	OCL_CHUNK( 40, LoadOldSign ),
-	OCL_CHUNK(256, LoadOldEngine ),
+
+	OCL_ASSERT( OC_TTO, 0x48C36 ),
+
+	OCL_CCHUNK( OC_TTD, 256, LoadOldEngine ),
+	OCL_CCHUNK( OC_TTO, 103, LoadOldEngine ),
+
+	OCL_ASSERT( OC_TTO, 0x496AC ),
 
 	OCL_VAR ( OC_UINT16,    1, &_vehicle_id_ctr_day ),
 
 	OCL_CHUNK(  8, LoadOldSubsidy ),
 
+	OCL_ASSERT( OC_TTO, 0x496CE ),
+
 	OCL_VAR ( OC_FILE_U16 | OC_VAR_U32,   1, &_next_competitor_start ),
+
+	OCL_CNULL( OC_TTO, 2 ),  ///< available monorail bitmask
+
 	OCL_VAR ( OC_FILE_I16 | OC_VAR_I32,   1, &_saved_scrollpos_x ),
 	OCL_VAR ( OC_FILE_I16 | OC_VAR_I32,   1, &_saved_scrollpos_y ),
 	OCL_VAR ( OC_FILE_U16 | OC_VAR_U8,    1, &_saved_scrollpos_zoom ),
@@ -1157,11 +1670,13 @@ static const OldChunks main_chunk[] = {
 
 	OCL_VAR ( OC_UINT16,    1, &_disaster_delay ),
 
-	OCL_NULL( 144 ),             ///< cargo-stuff, calculated in InitializeLandscapeVariables
+	OCL_ASSERT( OC_TTO, 0x496E4 ),
+
+	OCL_CNULL( OC_TTD, 144 ),             ///< cargo-stuff, calculated in InitializeLandscapeVariables
 
-	OCL_CHUNK(256, LoadOldEngineName ),
+	OCL_CCHUNK( OC_TTD, 256, LoadOldEngineName ),
 
-	OCL_NULL( 144 ),             ///< AI cargo-stuff, calculated in InitializeLandscapeVariables
+	OCL_CNULL( OC_TTD, 144 ),             ///< AI cargo-stuff, calculated in InitializeLandscapeVariables
 	OCL_NULL( 2 ),               ///< Company indexes of companies, no longer in use
 
 	OCL_VAR ( OC_FILE_U8 | OC_VAR_U16,    1, &_station_tick_ctr ),
@@ -1182,23 +1697,26 @@ static const OldChunks main_chunk[] = {
 
 	OCL_CHUNK( 1, LoadOldGameDifficulty ),
 
-	OCL_ASSERT( 0x77130 ),
+	OCL_ASSERT( OC_TTD, 0x77130 ),
 
 	OCL_VAR (  OC_UINT8,    1, &_settings_game.difficulty.diff_level ),
-	OCL_VAR (  OC_UINT8,    1, &_settings_game.game_creation.landscape ),
-	OCL_VAR (  OC_UINT8,    1, &_trees_tick_ctr ),
 
-	OCL_NULL( 1 ),               ///< Custom vehicle types yes/no, no longer used
-	OCL_VAR (  OC_UINT8,    1, &_settings_game.game_creation.snow_line ),
+	OCL_VAR ( OC_TTD | OC_UINT8,    1, &_settings_game.game_creation.landscape ),
+	OCL_VAR ( OC_TTD | OC_UINT8,    1, &_trees_tick_ctr ),
 
-	OCL_NULL( 32 ),              ///< new_industry_randtable, no longer used (because of new design)
-	OCL_NULL( 36 ),              ///< cargo-stuff, calculated in InitializeLandscapeVariables
+	OCL_CNULL( OC_TTD, 1 ),               ///< Custom vehicle types yes/no, no longer used
+	OCL_VAR ( OC_TTD | OC_UINT8,    1, &_settings_game.game_creation.snow_line ),
 
-	OCL_ASSERT( 0x77179 ),
+	OCL_CNULL( OC_TTD, 32 ),              ///< new_industry_randtable, no longer used (because of new design)
+	OCL_CNULL( OC_TTD, 36 ),              ///< cargo-stuff, calculated in InitializeLandscapeVariables
+
+	OCL_ASSERT( OC_TTD, 0x77179 ),
+	OCL_ASSERT( OC_TTO, 0x4971D ),
 
 	OCL_CHUNK( 1, LoadOldMapPart2 ),
 
-	OCL_ASSERT( 0x97179 ),
+	OCL_ASSERT( OC_TTD, 0x97179 ),
+	OCL_ASSERT( OC_TTO, 0x6971D ),
 
 	/* Below any (if available) extra chunks from TTDPatch can follow */
 	OCL_CHUNK(1, LoadTTDPatchExtraChunks),
@@ -1206,11 +1724,10 @@ static const OldChunks main_chunk[] = {
 	OCL_END()
 };
 
-bool LoadOldMain(LoadgameState *ls)
+bool LoadTTDMain(LoadgameState *ls)
 {
-	_savegame_type = SGT_TTD;
-	_ttdp_version = 0;
 	_read_ttdpatch_flags = false;
+	_ttdp_version = 0;
 
 	DEBUG(oldloader, 3, "Reading main chunk...");
 	/* Load the biggest chunk */
@@ -1224,13 +1741,13 @@ bool LoadOldMain(LoadgameState *ls)
 	}
 	DEBUG(oldloader, 3, "Done, converting game data...");
 
-	FixOldMapArray();
+	FixTTDMapArray();
 
 	/* Fix some general stuff */
 	_settings_game.game_creation.landscape = _settings_game.game_creation.landscape & 0xF;
 
 	/* Remap some pointers */
-	_cur_town_ctr      = REMAP_TOWN_IDX(_old_cur_town_ctr);
+	_cur_town_ctr      = RemapTownIndex(_old_cur_town_ctr);
 
 	/* Fix the game to be compatible with OpenTTD */
 	FixOldTowns();
@@ -1246,3 +1763,44 @@ bool LoadOldMain(LoadgameState *ls)
 
 	return true;
 }
+
+bool LoadTTOMain(LoadgameState *ls)
+{
+	DEBUG(oldloader, 3, "Reading main chunk...");
+
+	SmallStackSafeStackAlloc<byte, 103 * sizeof(Engine)> engines; // we don't want to call Engine constructor here
+	_old_engines = (Engine *)engines.data;
+	SmallStackSafeStackAlloc<StringID, 800> vehnames;
+	_old_vehicle_names = vehnames.data;
+
+	/* Load the biggest chunk */
+	if (!LoadChunk(ls, NULL, main_chunk)) {
+		DEBUG(oldloader, 0, "Loading failed");
+		return false;
+	}
+	DEBUG(oldloader, 3, "Done, converting game data...");
+
+	if (_settings_game.game_creation.town_name != 0) _settings_game.game_creation.town_name++;
+
+	_settings_game.game_creation.landscape = 0;
+	_trees_tick_ctr = 0xFF;
+
+	_cur_town_ctr = RemapTownIndex(_old_cur_town_ctr);
+
+	if (!FixTTOMapArray() || !FixTTOEngines()) {
+		DEBUG(oldloader, 0, "Conversion failed");
+		return false;
+	}
+
+	FixOldTowns();
+	FixOldVehicles();
+	FixTTOCompanies();
+
+	/* We have a new difficulty setting */
+	_settings_game.difficulty.town_council_tolerance = Clamp(_settings_game.difficulty.diff_level, 0, 2);
+
+	DEBUG(oldloader, 3, "Finished converting game data");
+	DEBUG(oldloader, 1, "TTO savegame successfully converted");
+
+	return true;
+}
diff --git a/src/saveload/saveload.h b/src/saveload/saveload.h
index f71b0dec4..ad79eb907 100644
--- a/src/saveload/saveload.h
+++ b/src/saveload/saveload.h
@@ -32,7 +32,9 @@ enum SavegameType {
 	SGT_TTD,    ///< TTD  savegame (can be detected incorrectly)
 	SGT_TTDP1,  ///< TTDP savegame ( -//- ) (data at NW border)
 	SGT_TTDP2,  ///< TTDP savegame in new format (data at SE border)
-	SGT_OTTD    ///< OTTD savegame
+	SGT_OTTD,   ///< OTTD savegame
+	SGT_TTO,    ///< TTO savegame
+	SGT_INVALID = 0xFF ///< broken savegame (used internally)
 };
 
 void GenerateDefaultSaveName(char *buf, const char *last);
diff --git a/src/saveload/saveload_internal.h b/src/saveload/saveload_internal.h
index 246f9e697..d364bebab 100644
--- a/src/saveload/saveload_internal.h
+++ b/src/saveload/saveload_internal.h
@@ -9,6 +9,7 @@
 #include "../company_manager_face.h"
 #include "../order_base.h"
 #include "../engine_type.h"
+#include "saveload.h"
 
 void InitializeOldNames();
 StringID RemapOldStringID(StringID s);
@@ -37,6 +38,9 @@ void CopyTempEngineData();
 extern int32 _saved_scrollpos_x;
 extern int32 _saved_scrollpos_y;
 
+extern SavegameType _savegame_type;
+extern uint32 _ttdp_version;
+
 CompanyManagerFace ConvertFromOldCompanyManagerFace(uint32 face);
 
 Order UnpackOldOrder(uint16 packed);
diff --git a/src/saveload/strings_sl.cpp b/src/saveload/strings_sl.cpp
index f436bdedf..e220d687a 100644
--- a/src/saveload/strings_sl.cpp
+++ b/src/saveload/strings_sl.cpp
@@ -8,6 +8,7 @@
 #include "../core/bitmath_func.hpp"
 #include "../core/alloc_func.hpp"
 #include "../string_func.h"
+#include "saveload_internal.h"
 
 #include "table/strings.h"
 
@@ -44,8 +45,8 @@ char *_old_name_array = NULL;
 
 /**
  * Copy and convert old custom names to UTF-8.
- * They were all stored in a 512 by 32 long string array and are
- * now stored with stations, waypoints and other places with names.
+ * They were all stored in a 512 by 32 (200 by 24 for TTO) long string array
+ * and are now stored with stations, waypoints and other places with names.
  * @param id the StringID of the custom name to clone.
  * @return the clones custom name.
  */
@@ -55,10 +56,11 @@ char *CopyFromOldName(StringID id)
 	if (GB(id, 11, 5) != 15) return NULL;
 
 	if (CheckSavegameVersion(37)) {
-		/* Old names were 32 characters long, so 128 characters should be
+		/* Old names were 24/32 characters long, so 128 characters should be
 		 * plenty to allow for expansion when converted to UTF-8. */
 		char tmp[128];
-		const char *strfrom = &_old_name_array[32 * GB(id, 0, 9)];
+		uint offs = _savegame_type == SGT_TTO ? 24 * GB(id, 0, 8) : 32 * GB(id, 0, 9);
+		const char *strfrom = &_old_name_array[offs];
 		char *strto = tmp;
 
 		for (; *strfrom != '\0'; strfrom++) {
@@ -109,7 +111,7 @@ void ResetOldNames()
 void InitializeOldNames()
 {
 	free(_old_name_array);
-	_old_name_array = CallocT<char>(512 * 32);
+	_old_name_array = CallocT<char>(512 * 32); // 200 * 24 would be enough for TTO savegames
 }
 
 static void Load_NAME()
diff --git a/src/vehicle_base.h b/src/vehicle_base.h
index c72ead86c..3113658f3 100644
--- a/src/vehicle_base.h
+++ b/src/vehicle_base.h
@@ -207,7 +207,7 @@ private:
 	Vehicle *previous_shared; ///< NOSAVE: pointer to the previous vehicle in the shared order chain
 public:
 	friend const SaveLoad *GetVehicleDescription(VehicleType vt); ///< So we can use private/protected variables in the saveload code
-	friend void AfterLoadVehicles(bool part_of_load);              ///< So we can set the previous and first pointers while loading
+	friend void AfterLoadVehicles(bool part_of_load);             ///< So we can set the previous and first pointers while loading
 	friend bool LoadOldVehicle(LoadgameState *ls, int num);       ///< So we can set the proper next pointer while loading
 
 	char *name;              ///< Name of vehicle