diff --git a/aircraft_cmd.c b/aircraft_cmd.c
--- a/aircraft_cmd.c
+++ b/aircraft_cmd.c
@@ -156,7 +156,7 @@ int32 CmdBuildAircraft(int x, int y, uin
 {
 	int32 value;
 	Vehicle *vl[3], *v, *u, *w;
-	byte unit_num;
+	UnitID unit_num;
 	uint tile = TILE_FROM_XY(x,y);
 	const AircraftVehicleInfo *avi = AircraftVehInfo(p1);
 	Engine *e;
diff --git a/roadveh_cmd.c b/roadveh_cmd.c
--- a/roadveh_cmd.c
+++ b/roadveh_cmd.c
@@ -113,7 +113,7 @@ int32 CmdBuildRoadVeh(int x, int y, uint
 {
 	int32 cost;
 	Vehicle *v;
-	byte unit_num;
+	UnitID unit_num;
 	uint tile = TILE_FROM_XY(x,y);
 	Engine *e;
 
diff --git a/saveload.c b/saveload.c
--- a/saveload.c
+++ b/saveload.c
@@ -7,7 +7,7 @@
 #include "saveload.h"
 
 enum {
-	SAVEGAME_MAJOR_VERSION = 7,
+	SAVEGAME_MAJOR_VERSION = 8,
 	SAVEGAME_MINOR_VERSION = 0,
 
 	SAVEGAME_LOADABLE_VERSION = (SAVEGAME_MAJOR_VERSION << 8) + SAVEGAME_MINOR_VERSION
diff --git a/settings.c b/settings.c
--- a/settings.c
+++ b/settings.c
@@ -867,10 +867,10 @@ const SettingDesc patch_settings[] = {
 	{"forbid_90_deg",				SDT_BOOL, 	(void*)false, &_patches.forbid_90_deg,					NULL},
 	{"improved_load",				SDT_BOOL,		(void*)false,	&_patches.improved_load,				NULL},
 
-	{"max_trains",					SDT_UINT8,	(void*)80,		&_patches.max_trains,						NULL},
-	{"max_roadveh",					SDT_UINT8,	(void*)80,		&_patches.max_roadveh,					NULL},
-	{"max_aircraft",				SDT_UINT8,	(void*)40,		&_patches.max_aircraft,					NULL},
-	{"max_ships",						SDT_UINT8,	(void*)50,		&_patches.max_ships,						NULL},
+	{"max_trains",					SDT_UINT16,	(void*)500,		&_patches.max_trains,						NULL},
+	{"max_roadveh",					SDT_UINT16,	(void*)500,		&_patches.max_roadveh,					NULL},
+	{"max_aircraft",				SDT_UINT16,	(void*)200,		&_patches.max_aircraft,					NULL},
+	{"max_ships",						SDT_UINT16,	(void*)300,		&_patches.max_ships,						NULL},
 
 	{"servint_ispercent",		SDT_BOOL,		(void*)false,	&_patches.servint_ispercent,		NULL},
 	{"servint_trains",			SDT_UINT16, (void*)150,		&_patches.servint_trains,				NULL},
diff --git a/settings_gui.c b/settings_gui.c
--- a/settings_gui.c
+++ b/settings_gui.c
@@ -661,10 +661,10 @@ static const PatchEntry _patches_vehicle
 	{PE_INT16,	PF_PLAYERBASED, STR_CONFIG_PATCHES_AUTORENEW_MONTHS, "autorenew_months", &_patches.autorenew_months,				-12, 12,  1, NULL},
 	{PE_CURRENCY, PF_PLAYERBASED, STR_CONFIG_PATCHES_AUTORENEW_MONEY,"autorenew_money", &_patches.autorenew_money,					0, 2000000, 100000, NULL},
 
-	{PE_UINT8,	0, STR_CONFIG_PATCHES_MAX_TRAINS,				"max_trains", &_patches.max_trains,								0,240, 10, NULL},
-	{PE_UINT8,	0, STR_CONFIG_PATCHES_MAX_ROADVEH,			"max_roadveh", &_patches.max_roadveh,							0,240, 10, NULL},
-	{PE_UINT8,	0, STR_CONFIG_PATCHES_MAX_AIRCRAFT,			"max_aircraft", &_patches.max_aircraft,							0,240, 10, NULL},
-	{PE_UINT8,	0, STR_CONFIG_PATCHES_MAX_SHIPS,				"max_ships", &_patches.max_ships,								0,240, 10, NULL},
+	{PE_UINT16,	0, STR_CONFIG_PATCHES_MAX_TRAINS,				"max_trains", &_patches.max_trains,								0,5000, 50, NULL},
+	{PE_UINT16,	0, STR_CONFIG_PATCHES_MAX_ROADVEH,			"max_roadveh", &_patches.max_roadveh,							0,5000, 50, NULL},
+	{PE_UINT16,	0, STR_CONFIG_PATCHES_MAX_AIRCRAFT,			"max_aircraft", &_patches.max_aircraft,						0,5000, 50, NULL},
+	{PE_UINT16,	0, STR_CONFIG_PATCHES_MAX_SHIPS,				"max_ships", &_patches.max_ships,									0,5000, 50, NULL},
 
 	{PE_BOOL,		0, STR_CONFIG_PATCHES_SERVINT_ISPERCENT,"servint_isperfect",&_patches.servint_ispercent,				0,  0,  0, &CheckInterval},
 	{PE_UINT16, PF_0ISDIS, STR_CONFIG_PATCHES_SERVINT_TRAINS,		"servint_trains",   &_patches.servint_trains,		5,800,  5, &InValidateDetailsWindow},
diff --git a/ship_cmd.c b/ship_cmd.c
--- a/ship_cmd.c
+++ b/ship_cmd.c
@@ -873,7 +873,7 @@ int32 CmdBuildShip(int x, int y, uint32 
 {
 	int32 value;
 	Vehicle *v;
-	uint unit_num;
+	UnitID unit_num;
 	uint tile = TILE_FROM_XY(x,y);
 	Engine *e;
 
diff --git a/train_cmd.c b/train_cmd.c
--- a/train_cmd.c
+++ b/train_cmd.c
@@ -535,7 +535,7 @@ int32 CmdBuildRailVehicle(int x, int y, 
 	const RailVehicleInfo *rvi;
 	int value,dir;
 	Vehicle *v, *u;
-	byte unit_num;
+	UnitID unit_num;
 	Engine *e;
 	uint tile = TILE_FROM_XY(x,y);
 
@@ -774,7 +774,7 @@ int32 CmdMoveRailVehicle(int x, int y, u
 
 	// moving a loco to a new line?, then we need to assign a unitnumber.
 	if (dst == NULL && src->subtype != TS_Front_Engine && is_loco) {
-		uint unit_num = GetFreeUnitNumber(VEH_Train);
+		UnitID unit_num = GetFreeUnitNumber(VEH_Train);
 		if (unit_num > _patches.max_trains)
 			return_cmd_error(STR_00E1_TOO_MANY_VEHICLES_IN_GAME);
 
diff --git a/variables.h b/variables.h
--- a/variables.h
+++ b/variables.h
@@ -11,6 +11,8 @@
 # define MAX_PATH 260
 #endif
 
+typedef uint16 UnitID;   //! All unitnumber stuff is of this type (or anyway, should be)
+
 // Prices and also the fractional part.
 VARDEF Prices _price;
 VARDEF uint16 _price_frac[NUM_PRICES];
@@ -135,10 +137,10 @@ typedef struct Patches {
 	uint8 toolbar_pos;			// position of toolbars, 0=left, 1=center, 2=right
 	uint8 window_snap_radius; // Windows snap at each other if closer than this
 
-	byte max_trains;				//max trains in game per player (these are 8bit because the unitnumber field can't hold more)
-	byte max_roadveh;				//max trucks in game per player
-	byte max_aircraft;			//max planes in game per player
-	byte max_ships;					//max ships in game per player
+	UnitID max_trains;				//max trains in game per player (these are 16bit because the unitnumber field can't hold more)
+	UnitID max_roadveh;				//max trucks in game per player
+	UnitID max_aircraft;			//max planes in game per player
+	UnitID max_ships;					//max ships in game per player
 
 	bool servint_ispercent;	// service intervals are in percents
 	uint16 servint_trains;	// service interval for trains
diff --git a/vehicle.c b/vehicle.c
--- a/vehicle.c
+++ b/vehicle.c
@@ -1762,9 +1762,9 @@ uint32 VehicleEnterTile(Vehicle *v, uint
 	return result;
 }
 
-uint GetFreeUnitNumber(byte type)
+UnitID GetFreeUnitNumber(byte type)
 {
-	uint unit_num = 0;
+	UnitID unit_num = 0;
 	Vehicle *u;
 
 restart:
@@ -1784,7 +1784,8 @@ const byte _common_veh_desc[] = {
 
 	SLE_REF(Vehicle,next,							REF_VEHICLE_OLD),
 	SLE_VAR(Vehicle,string_id,				SLE_STRINGID),
-	SLE_VAR(Vehicle,unitnumber,				SLE_UINT8),
+	SLE_CONDVAR(Vehicle,unitnumber,				SLE_FILE_U8 | SLE_VAR_U16, 0, 7),
+	SLE_CONDVAR(Vehicle,unitnumber,				SLE_UINT16, 8, 255),
 	SLE_VAR(Vehicle,owner,						SLE_UINT8),
 	SLE_CONDVAR(Vehicle,tile,					SLE_FILE_U16 | SLE_VAR_U32, 0, 5),
 	SLE_CONDVAR(Vehicle,tile,					SLE_UINT32, 6, 255),
diff --git a/vehicle.h b/vehicle.h
--- a/vehicle.h
+++ b/vehicle.h
@@ -100,7 +100,7 @@ struct Vehicle {
 
 	StringID string_id; // Displayed string
 
-	byte unitnumber;	// unit number, for display purposes only
+	UnitID unitnumber;	// unit number, for display purposes only
 	byte owner;				// which player owns the vehicle?
 
 	TileIndex tile;		// Current tile index
@@ -331,7 +331,7 @@ bool IsAircraftHangarTile(TileIndex tile
 void ShowAircraftViewWindow(Vehicle *v);
 
 bool IsShipDepotTile(TileIndex tile);
-uint GetFreeUnitNumber(byte type);
+UnitID GetFreeUnitNumber(byte type);
 
 int LoadUnloadVehicle(Vehicle *v);
 int GetDepotByTile(uint tile);