diff --git a/src/cmd_helper.h b/src/cmd_helper.h
index 1530beedb2..0b56fb7670 100644
--- a/src/cmd_helper.h
+++ b/src/cmd_helper.h
@@ -20,7 +20,8 @@ template<typename T, uint S, uint N, typename U> static inline T Extract(U v)
 	assert_tcompile(N == EnumPropsT<T>::num_bits);
 	assert_tcompile(S + N <= sizeof(U) * 8);
 	assert_tcompile(EnumPropsT<T>::end <= (1 << N));
-	return (T)GB(v, S, N);
+	U masked = GB(v, S, N);
+	return IsInsideMM(masked, EnumPropsT<T>::begin, EnumPropsT<T>::end) ? (T)masked : EnumPropsT<T>::invalid;
 }
 
 #endif
diff --git a/src/company_cmd.cpp b/src/company_cmd.cpp
index f738f07e08..93178dd804 100644
--- a/src/company_cmd.cpp
+++ b/src/company_cmd.cpp
@@ -15,6 +15,7 @@
 #include "company_gui.h"
 #include "town.h"
 #include "news_func.h"
+#include "cmd_helper.h"
 #include "command_func.h"
 #include "network/network.h"
 #include "network/network_func.h"
@@ -898,14 +899,11 @@ CommandCost CmdSetCompanyManagerFace(TileIndex tile, DoCommandFlag flags, uint32
  */
 CommandCost CmdSetCompanyColour(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
-	if (p2 >= 16) return CMD_ERROR; // max 16 colours
-
-	Colours colour = (Colours)p2;
-
-	LiveryScheme scheme = (LiveryScheme)GB(p1, 0, 8);
+	Colours colour = Extract<Colours, 0, 4>(p2);
+	LiveryScheme scheme = Extract<LiveryScheme, 0, 8>(p1);
 	byte state = GB(p1, 8, 2);
 
-	if (scheme >= LS_END || state >= 3) return CMD_ERROR;
+	if (scheme >= LS_END || state >= 3 || colour == INVALID_COLOUR) return CMD_ERROR;
 
 	Company *c = Company::Get(_current_company);
 
diff --git a/src/gfx_type.h b/src/gfx_type.h
index 8bb9c3ff47..167488766e 100644
--- a/src/gfx_type.h
+++ b/src/gfx_type.h
@@ -196,6 +196,7 @@ enum Colours {
 	COLOUR_END,
 	INVALID_COLOUR = 0xFF,
 };
+template <> struct EnumPropsT<Colours> : MakeEnumPropsT<Colours, byte, COLOUR_DARK_BLUE, COLOUR_END, INVALID_COLOUR, 4> {};
 
 /** Colour of the strings, see _string_colourmap in table/palettes.h or docs/ottd-colourtext-palette.png */
 enum TextColour {
diff --git a/src/group_cmd.cpp b/src/group_cmd.cpp
index a8475a18ff..6585d5084a 100644
--- a/src/group_cmd.cpp
+++ b/src/group_cmd.cpp
@@ -10,6 +10,7 @@
 /** @file group_cmd.cpp Handling of the engine groups */
 
 #include "stdafx.h"
+#include "cmd_helper.h"
 #include "command_func.h"
 #include "group.h"
 #include "train.h"
@@ -82,7 +83,7 @@ void InitializeGroup()
  */
 CommandCost CmdCreateGroup(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
-	VehicleType vt = (VehicleType)p1;
+	VehicleType vt = Extract<VehicleType, 0, 3>(p1);
 	if (!IsCompanyBuildableVehicleType(vt)) return CMD_ERROR;
 
 	if (!Group::CanAllocateItem()) return CMD_ERROR;
@@ -258,13 +259,12 @@ CommandCost CmdAddVehicleGroup(TileIndex tile, DoCommandFlag flags, uint32 p1, u
  */
 CommandCost CmdAddSharedVehicleGroup(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
-	VehicleType type = (VehicleType)p2;
-	if (!Group::IsValidID(p1) || !IsCompanyBuildableVehicleType(type)) return CMD_ERROR;
+	VehicleType type = Extract<VehicleType, 0, 3>(p2);
+	GroupID id_g = p1;
+	if (!Group::IsValidID(id_g) || !IsCompanyBuildableVehicleType(type)) return CMD_ERROR;
 
 	if (flags & DC_EXEC) {
 		Vehicle *v;
-		VehicleType type = (VehicleType)p2;
-		GroupID id_g = p1;
 
 		/* Find the first front engine which belong to the group id_g
 		 * then add all shared vehicles of this front engine to the group id_g */
@@ -298,13 +298,13 @@ CommandCost CmdAddSharedVehicleGroup(TileIndex tile, DoCommandFlag flags, uint32
  */
 CommandCost CmdRemoveAllVehiclesGroup(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
-	Group *g = Group::GetIfValid(p1);
-	VehicleType type = (VehicleType)p2;
+	GroupID old_g = p1;
+	Group *g = Group::GetIfValid(old_g);
+	VehicleType type = Extract<VehicleType, 0, 3>(p2);
 
 	if (g == NULL || g->owner != _current_company || !IsCompanyBuildableVehicleType(type)) return CMD_ERROR;
 
 	if (flags & DC_EXEC) {
-		GroupID old_g = p1;
 		Vehicle *v;
 
 		/* Find each Vehicle that belongs to the group old_g and add it to the default group */
diff --git a/src/livery.h b/src/livery.h
index 79309d517a..d34e4c47e3 100644
--- a/src/livery.h
+++ b/src/livery.h
@@ -55,6 +55,7 @@ enum LiveryScheme {
 };
 
 DECLARE_POSTFIX_INCREMENT(LiveryScheme)
+template <> struct EnumPropsT<LiveryScheme> : MakeEnumPropsT<LiveryScheme, byte, LS_BEGIN, LS_END, LS_END, 8> {};
 
 /* List of different livery classes, used only by the livery GUI. */
 enum LiveryClass {
diff --git a/src/newgrf_station.h b/src/newgrf_station.h
index 0ccf0924f7..9d803b7dff 100644
--- a/src/newgrf_station.h
+++ b/src/newgrf_station.h
@@ -27,6 +27,7 @@ enum StationClassID {
 	STAT_CLASS_MAX = 32,     ///< Maximum number of classes.
 };
 typedef SimpleTinyEnumT<StationClassID, byte> StationClassIDByte;
+template <> struct EnumPropsT<StationClassID> : MakeEnumPropsT<StationClassID, byte, STAT_CLASS_BEGIN, STAT_CLASS_MAX, STAT_CLASS_MAX, 8> {};
 
 /** Allow incrementing of StationClassID variables */
 DECLARE_POSTFIX_INCREMENT(StationClassID)
diff --git a/src/order_cmd.cpp b/src/order_cmd.cpp
index 7bbcbb86b0..5f0fe41490 100644
--- a/src/order_cmd.cpp
+++ b/src/order_cmd.cpp
@@ -11,6 +11,7 @@
 
 #include "stdafx.h"
 #include "debug.h"
+#include "cmd_helper.h"
 #include "command_func.h"
 #include "company_func.h"
 #include "news_func.h"
@@ -933,8 +934,8 @@ CommandCost CmdModifyOrder(TileIndex tile, DoCommandFlag flags, uint32 p1, uint3
 {
 	VehicleOrderID sel_ord = GB(p1, 16, 16); // XXX - automatically truncated to 8 bits.
 	VehicleID veh          = GB(p1,  0, 16);
-	ModifyOrderFlags mof   = (ModifyOrderFlags)GB(p2,  0,  4);
-	uint16 data             = GB(p2, 4, 11);
+	ModifyOrderFlags mof   = Extract<ModifyOrderFlags, 0, 4>(p2);
+	uint16 data            = GB(p2, 4, 11);
 
 	if (mof >= MOF_END) return CMD_ERROR;
 
diff --git a/src/order_type.h b/src/order_type.h
index 8c66d22961..757603fcb8 100644
--- a/src/order_type.h
+++ b/src/order_type.h
@@ -149,6 +149,7 @@ enum ModifyOrderFlags {
 	MOF_COND_DESTINATION,///< Change the destination of a conditional order.
 	MOF_END
 };
+template <> struct EnumPropsT<ModifyOrderFlags> : MakeEnumPropsT<ModifyOrderFlags, byte, MOF_NON_STOP, MOF_END, MOF_END, 4> {};
 
 /**
  * Depot action to switch to when doing a MOF_DEPOT_ACTION.
diff --git a/src/rail.cpp b/src/rail.cpp
index 663753e9f3..21ae806614 100644
--- a/src/rail.cpp
+++ b/src/rail.cpp
@@ -181,7 +181,7 @@ bool HasRailtypeAvail(const CompanyID company, const RailType railtype)
 
 bool ValParamRailtype(const RailType rail)
 {
-	return HasRailtypeAvail(_current_company, rail);
+	return rail < RAILTYPE_END && HasRailtypeAvail(_current_company, rail);
 }
 
 RailType GetBestRailtype(const CompanyID company)
diff --git a/src/rail_cmd.cpp b/src/rail_cmd.cpp
index f90be41257..de9b2543d6 100644
--- a/src/rail_cmd.cpp
+++ b/src/rail_cmd.cpp
@@ -358,8 +358,8 @@ static inline bool ValParamTrackOrientation(Track track)
  */
 CommandCost CmdBuildSingleRail(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
-	RailType railtype = (RailType)p1;
-	Track track = (Track)p2;
+	RailType railtype = Extract<RailType, 0, 4>(p1);
+	Track track = Extract<Track, 0, 3>(p2);
 	CommandCost cost(EXPENSES_CONSTRUCTION);
 
 	if (!ValParamRailtype(railtype) || !ValParamTrackOrientation(track)) return CMD_ERROR;
@@ -499,11 +499,11 @@ CommandCost CmdBuildSingleRail(TileIndex tile, DoCommandFlag flags, uint32 p1, u
  */
 CommandCost CmdRemoveSingleRail(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
-	Track track = (Track)p2;
+	Track track = Extract<Track, 0, 3>(p2);
 	CommandCost cost(EXPENSES_CONSTRUCTION);
 	bool crossing = false;
 
-	if (!ValParamTrackOrientation((Track)p2)) return CMD_ERROR;
+	if (!ValParamTrackOrientation(track)) return CMD_ERROR;
 	TrackBits trackbit = TrackToTrackBits(track);
 
 	/* Need to read tile owner now because it may change when the rail is removed
@@ -741,9 +741,9 @@ static CommandCost ValidateAutoDrag(Trackdir *trackdir, TileIndex start, TileInd
 static CommandCost CmdRailTrackHelper(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
 	CommandCost total_cost(EXPENSES_CONSTRUCTION);
-	Track track = (Track)GB(p2, 4, 3);
+	Track track = Extract<Track, 4, 3>(p2);
 	bool remove = HasBit(p2, 7);
-	RailType railtype = (RailType)GB(p2, 0, 4);
+	RailType railtype = Extract<RailType, 0, 4>(p2);
 
 	if (!ValParamRailtype(railtype) || !ValParamTrackOrientation(track)) return CMD_ERROR;
 	if (p1 >= MapSize()) return CMD_ERROR;
@@ -833,7 +833,8 @@ CommandCost CmdRemoveRailroadTrack(TileIndex tile, DoCommandFlag flags, uint32 p
 CommandCost CmdBuildTrainDepot(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
 	/* check railtype and valid direction for depot (0 through 3), 4 in total */
-	if (!ValParamRailtype((RailType)p1)) return CMD_ERROR;
+	RailType railtype = Extract<RailType, 0, 4>(p1);
+	if (!ValParamRailtype(railtype)) return CMD_ERROR;
 
 	Slope tileh = GetTileSlope(tile, NULL);
 
@@ -865,7 +866,7 @@ CommandCost CmdBuildTrainDepot(TileIndex tile, DoCommandFlag flags, uint32 p1, u
 		Depot *d = new Depot(tile);
 		d->town_index = ClosestTownFromTile(tile, UINT_MAX)->index;
 
-		MakeRailDepot(tile, _current_company, d->index, dir, (RailType)p1);
+		MakeRailDepot(tile, _current_company, d->index, dir, railtype);
 		MarkTileDirtyByTile(tile);
 
 		AddSideToSignalBuffer(tile, INVALID_DIAGDIR, _current_company);
@@ -898,16 +899,17 @@ CommandCost CmdBuildTrainDepot(TileIndex tile, DoCommandFlag flags, uint32 p1, u
  */
 CommandCost CmdBuildSingleSignal(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
-	Track track = (Track)GB(p1, 0, 3);
+	Track track = Extract<Track, 0, 3>(p1);
 	bool ctrl_pressed = HasBit(p1, 3); // was the CTRL button pressed
 	SignalVariant sigvar = (ctrl_pressed ^ HasBit(p1, 4)) ? SIG_SEMAPHORE : SIG_ELECTRIC; // the signal variant of the new signal
-	SignalType sigtype = (SignalType)GB(p1, 5, 3); // the signal type of the new signal
+	SignalType sigtype = Extract<SignalType, 5, 3>(p1); // the signal type of the new signal
 	bool convert_signal = HasBit(p1, 8); // convert button pressed
-	SignalType cycle_start = (SignalType)GB(p1, 9, 3);
-	SignalType cycle_stop = (SignalType)GB(p1, 12, 3);
+	SignalType cycle_start = Extract<SignalType, 9, 3>(p1);
+	SignalType cycle_stop = Extract<SignalType, 12, 3>(p1);
 	uint num_dir_cycle = GB(p1, 15, 2);
 
 	if (sigtype > SIGTYPE_LAST) return CMD_ERROR;
+	if (cycle_start > cycle_stop || cycle_stop > SIGTYPE_LAST) return CMD_ERROR;
 
 	/* You can only build signals on plain rail tiles, and the selected track must exist */
 	if (!ValParamTrackOrientation(track) || !IsPlainRailTile(tile) ||
@@ -1127,15 +1129,14 @@ static CommandCost CmdSignalTrackHelper(TileIndex tile, DoCommandFlag flags, uin
 	CommandCost total_cost(EXPENSES_CONSTRUCTION);
 	TileIndex start_tile = tile;
 
-	Track track = (Track)GB(p2, 0, 3);
+	Track track = Extract<Track, 0, 3>(p2);
 	bool mode = HasBit(p2, 3);
 	bool semaphores = HasBit(p2, 4);
 	bool remove = HasBit(p2, 5);
 	bool autofill = HasBit(p2, 6);
-	Trackdir trackdir = TrackToTrackdir(track);
 	byte signal_density = GB(p2, 24, 8);
 
-	if (p1 >= MapSize()) return CMD_ERROR;
+	if (p1 >= MapSize() || !ValParamTrackOrientation(track)) return CMD_ERROR;
 	TileIndex end_tile = p1;
 	if (signal_density == 0 || signal_density > 20) return CMD_ERROR;
 
@@ -1145,6 +1146,7 @@ static CommandCost CmdSignalTrackHelper(TileIndex tile, DoCommandFlag flags, uin
 	 * since the original amount will be too dense (shorter tracks) */
 	signal_density *= 2;
 
+	Trackdir trackdir = TrackToTrackdir(track);
 	CommandCost ret = ValidateAutoDrag(&trackdir, tile, end_tile);
 	if (ret.Failed()) return ret;
 
@@ -1271,7 +1273,7 @@ CommandCost CmdBuildSignalTrack(TileIndex tile, DoCommandFlag flags, uint32 p1,
  */
 CommandCost CmdRemoveSingleSignal(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
-	Track track = (Track)GB(p1, 0, 3);
+	Track track = Extract<Track, 0, 3>(p1);
 
 	if (!ValParamTrackOrientation(track) ||
 			!IsPlainRailTile(tile) ||
@@ -1374,7 +1376,7 @@ static Vehicle *UpdateTrainPowerProc(Vehicle *v, void *data)
  */
 CommandCost CmdConvertRail(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
-	RailType totype = (RailType)p2;
+	RailType totype = Extract<RailType, 0, 4>(p2);
 
 	if (!ValParamRailtype(totype)) return CMD_ERROR;
 	if (p1 >= MapSize()) return CMD_ERROR;
diff --git a/src/rail_type.h b/src/rail_type.h
index 9b0b34e4b0..e93fd9f0fd 100644
--- a/src/rail_type.h
+++ b/src/rail_type.h
@@ -43,7 +43,7 @@ enum RailType {
 /** Allow incrementing of Track variables */
 DECLARE_POSTFIX_INCREMENT(RailType)
 /** Define basic enum properties */
-template <> struct EnumPropsT<RailType> : MakeEnumPropsT<RailType, byte, RAILTYPE_BEGIN, RAILTYPE_END, INVALID_RAILTYPE> {};
+template <> struct EnumPropsT<RailType> : MakeEnumPropsT<RailType, byte, RAILTYPE_BEGIN, RAILTYPE_END, INVALID_RAILTYPE, 4> {};
 typedef TinyEnumT<RailType> RailTypeByte;
 
 /**
diff --git a/src/road_cmd.cpp b/src/road_cmd.cpp
index 8f3832dc6e..10b9027142 100644
--- a/src/road_cmd.cpp
+++ b/src/road_cmd.cpp
@@ -469,10 +469,10 @@ CommandCost CmdBuildRoad(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32
 	/* do not allow building 'zero' road bits, code wouldn't handle it */
 	if (pieces == ROAD_NONE) return CMD_ERROR;
 
-	RoadType rt = (RoadType)GB(p1, 4, 2);
+	RoadType rt = Extract<RoadType, 4, 2>(p1);
 	if (!IsValidRoadType(rt) || !ValParamRoadType(rt)) return CMD_ERROR;
 
-	DisallowedRoadDirections toggle_drd = (DisallowedRoadDirections)GB(p1, 6, 2);
+	DisallowedRoadDirections toggle_drd = Extract<DisallowedRoadDirections, 6, 2>(p1);
 
 	Slope tileh = GetTileSlope(tile, NULL);
 
@@ -726,7 +726,7 @@ CommandCost CmdBuildLongRoad(TileIndex start_tile, DoCommandFlag flags, uint32 p
 	if (p1 >= MapSize()) return CMD_ERROR;
 
 	TileIndex end_tile = p1;
-	RoadType rt = (RoadType)GB(p2, 3, 2);
+	RoadType rt = Extract<RoadType, 3, 2>(p2);
 	if (!IsValidRoadType(rt) || !ValParamRoadType(rt)) return CMD_ERROR;
 
 	Axis axis = Extract<Axis, 2, 1>(p2);
@@ -818,7 +818,7 @@ CommandCost CmdRemoveLongRoad(TileIndex start_tile, DoCommandFlag flags, uint32
 	if (p1 >= MapSize()) return CMD_ERROR;
 
 	TileIndex end_tile = p1;
-	RoadType rt = (RoadType)GB(p2, 3, 2);
+	RoadType rt = Extract<RoadType, 3, 2>(p2);
 	if (!IsValidRoadType(rt)) return CMD_ERROR;
 
 	Axis axis = Extract<Axis, 2, 1>(p2);
@@ -887,7 +887,7 @@ CommandCost CmdRemoveLongRoad(TileIndex start_tile, DoCommandFlag flags, uint32
 CommandCost CmdBuildRoadDepot(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
 	DiagDirection dir = Extract<DiagDirection, 0, 2>(p1);
-	RoadType rt = (RoadType)GB(p1, 2, 2);
+	RoadType rt = Extract<RoadType, 2, 2>(p1);
 
 	if (!IsValidRoadType(rt) || !ValParamRoadType(rt)) return CMD_ERROR;
 
diff --git a/src/road_map.h b/src/road_map.h
index e5e738cb4b..ad5a1de4a9 100644
--- a/src/road_map.h
+++ b/src/road_map.h
@@ -168,6 +168,7 @@ enum DisallowedRoadDirections {
 	DRD_END
 };
 DECLARE_ENUM_AS_BIT_SET(DisallowedRoadDirections)
+template <> struct EnumPropsT<DisallowedRoadDirections> : MakeEnumPropsT<DisallowedRoadDirections, byte, DRD_NONE, DRD_END, DRD_END, 2> {};
 
 /**
  * Gets the disallowed directions
diff --git a/src/road_type.h b/src/road_type.h
index be16c23152..7a3a2f9ae5 100644
--- a/src/road_type.h
+++ b/src/road_type.h
@@ -27,7 +27,7 @@ enum RoadType {
 	INVALID_ROADTYPE = 0xFF ///< flag for invalid roadtype
 };
 DECLARE_POSTFIX_INCREMENT(RoadType)
-template <> struct EnumPropsT<RoadType> : MakeEnumPropsT<RoadType, byte, ROADTYPE_BEGIN, ROADTYPE_END, INVALID_ROADTYPE> {};
+template <> struct EnumPropsT<RoadType> : MakeEnumPropsT<RoadType, byte, ROADTYPE_BEGIN, ROADTYPE_END, INVALID_ROADTYPE, 2> {};
 
 /**
  * The different roadtypes we support, but then a bitmask of them
@@ -42,6 +42,7 @@ enum RoadTypes {
 	INVALID_ROADTYPES  = 0xFF                              ///< Invalid roadtypes
 };
 DECLARE_ENUM_AS_BIT_SET(RoadTypes)
+template <> struct EnumPropsT<RoadTypes> : MakeEnumPropsT<RoadTypes, byte, ROADTYPES_NONE, ROADTYPES_END, INVALID_ROADTYPES, 2> {};
 typedef SimpleTinyEnumT<RoadTypes, byte> RoadTypesByte;
 
 
diff --git a/src/signal_type.h b/src/signal_type.h
index 8c9c4bcfc2..5a8d564d2a 100644
--- a/src/signal_type.h
+++ b/src/signal_type.h
@@ -27,9 +27,12 @@ enum SignalType {
 	SIGTYPE_COMBO      = 3, ///< presignal inter-block
 	SIGTYPE_PBS        = 4, ///< normal pbs signal
 	SIGTYPE_PBS_ONEWAY = 5, ///< no-entry signal
+
+	SIGTYPE_END,
 	SIGTYPE_LAST       = SIGTYPE_PBS_ONEWAY,
 	SIGTYPE_LAST_NOPBS = SIGTYPE_COMBO
 };
+template <> struct EnumPropsT<SignalType> : MakeEnumPropsT<SignalType, byte, SIGTYPE_NORMAL, SIGTYPE_END, SIGTYPE_END, 3> {};
 
 
 #endif /* SIGNAL_TYPE_H */
diff --git a/src/station_cmd.cpp b/src/station_cmd.cpp
index 060b66bf61..13d16f962e 100644
--- a/src/station_cmd.cpp
+++ b/src/station_cmd.cpp
@@ -1095,13 +1095,13 @@ CommandCost FindJoiningWaypoint(StationID existing_waypoint, StationID waypoint_
 CommandCost CmdBuildRailStation(TileIndex tile_org, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
 	/* Unpack parameters */
-	RailType rt    = (RailType)GB(p1, 0, 4);
+	RailType rt    = Extract<RailType, 0, 4>(p1);
 	Axis axis      = Extract<Axis, 4, 1>(p1);
 	byte numtracks = GB(p1,  8, 8);
 	byte plat_len  = GB(p1, 16, 8);
 	bool adjacent  = HasBit(p1, 24);
 
-	StationClassID spec_class = (StationClassID)GB(p2, 0, 8);
+	StationClassID spec_class = Extract<StationClassID, 0, 8>(p2);
 	byte spec_index           = GB(p2, 8, 8);
 	StationID station_to_join = GB(p2, 16, 16);
 
@@ -1112,7 +1112,7 @@ CommandCost CmdBuildRailStation(TileIndex tile_org, DoCommandFlag flags, uint32
 	if (!ValParamRailtype(rt)) return CMD_ERROR;
 
 	/* Check if the given station class is valid */
-	if ((uint)spec_class >= GetNumStationClasses()) return CMD_ERROR;
+	if ((uint)spec_class >= GetNumStationClasses() || spec_class == STAT_CLASS_WAYP) return CMD_ERROR;
 	if (spec_index >= GetNumCustomStations(spec_class)) return CMD_ERROR;
 	if (plat_len == 0 || numtracks == 0) return CMD_ERROR;
 
@@ -1675,7 +1675,7 @@ CommandCost CmdBuildRoadStop(TileIndex tile, DoCommandFlag flags, uint32 p1, uin
 {
 	bool type = HasBit(p2, 0);
 	bool is_drive_through = HasBit(p2, 1);
-	RoadTypes rts = (RoadTypes)GB(p2, 2, 2);
+	RoadTypes rts = Extract<RoadTypes, 2, 2>(p2);
 	StationID station_to_join = GB(p2, 16, 16);
 	bool reuse = (station_to_join != NEW_STATION);
 	if (!reuse) station_to_join = INVALID_STATION;
@@ -1702,7 +1702,7 @@ CommandCost CmdBuildRoadStop(TileIndex tile, DoCommandFlag flags, uint32 p1, uin
 	/* Trams only have drive through stops */
 	if (!is_drive_through && HasBit(rts, ROADTYPE_TRAM)) return CMD_ERROR;
 
-	DiagDirection ddir = (DiagDirection)GB(p2, 6, 2);
+	DiagDirection ddir = Extract<DiagDirection, 6, 2>(p2);
 
 	/* Safeguard the parameters. */
 	if (!IsValidDiagDirection(ddir)) return CMD_ERROR;
diff --git a/src/town_cmd.cpp b/src/town_cmd.cpp
index c4f10b072b..a772030140 100644
--- a/src/town_cmd.cpp
+++ b/src/town_cmd.cpp
@@ -14,6 +14,7 @@
 #include "road_cmd.h"
 #include "landscape.h"
 #include "viewport_func.h"
+#include "cmd_helper.h"
 #include "command_func.h"
 #include "industry.h"
 #include "station_base.h"
@@ -1518,9 +1519,9 @@ static bool IsUniqueTownName(const char *name)
  */
 CommandCost CmdFoundTown(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
-	TownSize size = (TownSize)GB(p1, 0, 2);
+	TownSize size = Extract<TownSize, 0, 2>(p1);
 	bool city = HasBit(p1, 2);
-	TownLayout layout = (TownLayout)GB(p1, 3, 3);
+	TownLayout layout = Extract<TownLayout, 3, 3>(p1);
 	TownNameParams par(_settings_game.game_creation.town_name);
 	bool random = HasBit(p1, 6);
 	uint32 townnameparts = p2;
diff --git a/src/town_type.h b/src/town_type.h
index 320653011c..93dcc1a3af 100644
--- a/src/town_type.h
+++ b/src/town_type.h
@@ -26,6 +26,7 @@ enum TownSize {
 
 	TSZ_END,    ///< Number of available town sizes.
 };
+template <> struct EnumPropsT<TownSize> : MakeEnumPropsT<TownSize, byte, TSZ_SMALL, TSZ_END, TSZ_END, 2> {};
 
 enum {
 	/* These refer to the maximums, so Appalling is -1000 to -400
@@ -89,6 +90,7 @@ enum TownLayout {
 
 	NUM_TLS,             ///< Number of town layouts
 };
+template <> struct EnumPropsT<TownLayout> : MakeEnumPropsT<TownLayout, byte, TL_BEGIN, NUM_TLS, NUM_TLS, 3> {};
 /** It needs to be 8bits, because we save and load it as such */
 typedef SimpleTinyEnumT<TownLayout, byte> TownLayoutByte; // typedefing-enumification of TownLayout
 
diff --git a/src/transport_type.h b/src/transport_type.h
index 71b452b5f5..65af9c75b3 100644
--- a/src/transport_type.h
+++ b/src/transport_type.h
@@ -30,5 +30,6 @@ enum TransportType {
 	TRANSPORT_END,
 	INVALID_TRANSPORT = 0xff,
 };
+template <> struct EnumPropsT<TransportType> : MakeEnumPropsT<TransportType, byte, TRANSPORT_BEGIN, TRANSPORT_END, INVALID_TRANSPORT, 2> {};
 
 #endif /* TRANSPORT_TYPE_H */
diff --git a/src/tunnelbridge_cmd.cpp b/src/tunnelbridge_cmd.cpp
index aaa8b7e7f3..4e1d763fd8 100644
--- a/src/tunnelbridge_cmd.cpp
+++ b/src/tunnelbridge_cmd.cpp
@@ -17,6 +17,7 @@
 #include "landscape.h"
 #include "unmovable_map.h"
 #include "viewport_func.h"
+#include "cmd_helper.h"
 #include "command_func.h"
 #include "town.h"
 #include "variables.h"
@@ -194,7 +195,7 @@ CommandCost CheckBridgeAvailability(BridgeType bridge_type, uint bridge_len, DoC
  * @param p1 packed start tile coords (~ dx)
  * @param p2 various bitstuffed elements
  * - p2 = (bit  0- 7) - bridge type (hi bh)
- * - p2 = (bit  8-14) - rail type or road types.
+ * - p2 = (bit  8-11) - rail type or road types.
  * - p2 = (bit 15-16) - transport type.
  * @param text unused
  * @return the cost of this operation or an error
@@ -209,17 +210,17 @@ CommandCost CmdBuildBridge(TileIndex end_tile, DoCommandFlag flags, uint32 p1, u
 
 	if (p1 >= MapSize()) return CMD_ERROR;
 
-	TransportType transport_type = (TransportType)GB(p2, 15, 2);
+	TransportType transport_type = Extract<TransportType, 15, 2>(p2);
 
 	/* type of bridge */
 	switch (transport_type) {
 		case TRANSPORT_ROAD:
-			roadtypes = (RoadTypes)GB(p2, 8, 2);
+			roadtypes = Extract<RoadTypes, 8, 2>(p2);
 			if (!HasExactlyOneBit(roadtypes) || !HasRoadTypesAvail(_current_company, roadtypes)) return CMD_ERROR;
 			break;
 
 		case TRANSPORT_RAIL:
-			railtype = (RailType)GB(p2, 8, 7);
+			railtype = Extract<RailType, 8, 4>(p2);
 			if (!ValParamRailtype(railtype)) return CMD_ERROR;
 			break;
 
@@ -490,19 +491,19 @@ CommandCost CmdBuildBridge(TileIndex end_tile, DoCommandFlag flags, uint32 p1, u
  */
 CommandCost CmdBuildTunnel(TileIndex start_tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
-	TransportType transport_type = (TransportType)GB(p1, 8, 2);
+	TransportType transport_type = Extract<TransportType, 8, 2>(p1);
 
 	RailType railtype = INVALID_RAILTYPE;
 	RoadTypes rts = ROADTYPES_NONE;
 	_build_tunnel_endtile = 0;
 	switch (transport_type) {
 		case TRANSPORT_RAIL:
-			railtype = (RailType)GB(p1, 0, 4);
+			railtype = Extract<RailType, 0, 4>(p1);
 			if (!ValParamRailtype(railtype)) return CMD_ERROR;
 			break;
 
 		case TRANSPORT_ROAD:
-			rts = (RoadTypes)GB(p1, 0, 2);
+			rts = Extract<RoadTypes, 0, 2>(p1);
 			if (!HasExactlyOneBit(rts) || !HasRoadTypesAvail(_current_company, rts)) return CMD_ERROR;
 			break;
 
diff --git a/src/vehicle_cmd.cpp b/src/vehicle_cmd.cpp
index 892d05c524..1d3963162a 100644
--- a/src/vehicle_cmd.cpp
+++ b/src/vehicle_cmd.cpp
@@ -13,6 +13,7 @@
 #include "roadveh.h"
 #include "news_func.h"
 #include "airport.h"
+#include "cmd_helper.h"
 #include "command_func.h"
 #include "company_func.h"
 #include "vehicle_gui.h"
@@ -126,17 +127,19 @@ CommandCost CmdStartStopVehicle(TileIndex tile, DoCommandFlag flags, uint32 p1,
  *   - bit 0-4 Vehicle type
  *   - bit 5 false = start vehicles, true = stop vehicles
  *   - bit 6 if set, then it's a vehicle list window, not a depot and Tile is ignored in this case
- *   - bit 8-11 Vehicle List Window type (ignored unless bit 1 is set)
+ *   - bit 8-11 Vehicle List Window type (ignored unless bit 6 is set)
  * @param text unused
  * @return the cost of this operation or an error
  */
 CommandCost CmdMassStartStopVehicle(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
 	VehicleList list;
-	VehicleType vehicle_type = (VehicleType)GB(p2, 0, 5);
+	VehicleType vehicle_type = Extract<VehicleType, 0, 3>(p2);
 	bool start_stop = HasBit(p2, 5);
 	bool vehicle_list_window = HasBit(p2, 6);
 
+	if (!IsCompanyBuildableVehicleType(vehicle_type)) return CMD_ERROR;
+
 	if (vehicle_list_window) {
 		uint32 id = p1;
 		uint16 window_type = p2 & VLW_MASK;
@@ -180,9 +183,11 @@ CommandCost CmdDepotSellAllVehicles(TileIndex tile, DoCommandFlag flags, uint32
 	VehicleList list;
 
 	CommandCost cost(EXPENSES_NEW_VEHICLES);
-	VehicleType vehicle_type = (VehicleType)GB(p1, 0, 8);
+	VehicleType vehicle_type = Extract<VehicleType, 0, 3>(p1);
 	uint sell_command = GetCmdSellVeh(vehicle_type);
 
+	if (!IsCompanyBuildableVehicleType(vehicle_type)) return CMD_ERROR;
+
 	/* Get the list of vehicles in the depot */
 	BuildDepotVehicleList(vehicle_type, tile, &list, &list);
 
@@ -214,8 +219,9 @@ CommandCost CmdDepotMassAutoReplace(TileIndex tile, DoCommandFlag flags, uint32
 {
 	VehicleList list;
 	CommandCost cost = CommandCost(EXPENSES_NEW_VEHICLES);
-	VehicleType vehicle_type = (VehicleType)GB(p1, 0, 8);
+	VehicleType vehicle_type = Extract<VehicleType, 0, 3>(p1);
 
+	if (!IsCompanyBuildableVehicleType(vehicle_type)) return CMD_ERROR;
 	if (!IsDepotTile(tile) || !IsTileOwner(tile, _current_company)) return CMD_ERROR;
 
 	/* Get the list of vehicles in the depot */
diff --git a/src/vehicle_type.h b/src/vehicle_type.h
index 900d54f99a..9ebe5ed697 100644
--- a/src/vehicle_type.h
+++ b/src/vehicle_type.h
@@ -28,6 +28,7 @@ enum VehicleType {
 	VEH_INVALID = 0xFF, ///< Non-existing type of vehicle.
 };
 DECLARE_POSTFIX_INCREMENT(VehicleType)
+template <> struct EnumPropsT<VehicleType> : MakeEnumPropsT<VehicleType, byte, VEH_TRAIN, VEH_END, VEH_INVALID, 3> {};
 /** It needs to be 8bits, because we save and load it as such */
 typedef SimpleTinyEnumT<VehicleType, byte> VehicleTypeByte;
 
diff --git a/src/water_cmd.cpp b/src/water_cmd.cpp
index 4b80d0cd4e..805f46d29c 100644
--- a/src/water_cmd.cpp
+++ b/src/water_cmd.cpp
@@ -291,7 +291,7 @@ CommandCost CmdBuildLock(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32
  */
 CommandCost CmdBuildCanal(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
-	if (p1 >= MapSize()) return CMD_ERROR;
+	if (p1 >= MapSize() || p2 > 2) return CMD_ERROR;
 
 	/* Outside of the editor you can only build canals, not oceans */
 	if (p2 != 0 && _game_mode != GM_EDITOR) return CMD_ERROR;
diff --git a/src/waypoint_cmd.cpp b/src/waypoint_cmd.cpp
index 8771f27aaa..5e8ce29bde 100644
--- a/src/waypoint_cmd.cpp
+++ b/src/waypoint_cmd.cpp
@@ -11,6 +11,7 @@
 
 #include "stdafx.h"
 
+#include "cmd_helper.h"
 #include "command_func.h"
 #include "landscape.h"
 #include "bridge_map.h"
@@ -215,12 +216,12 @@ extern CommandCost CanExpandRailStation(const BaseStation *st, TileArea &new_ta,
 CommandCost CmdBuildRailWaypoint(TileIndex start_tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
 {
 	/* Unpack parameters */
-	Axis axis      = (Axis)GB(p1,  4, 1);
+	Axis axis      = Extract<Axis, 4, 1>(p1);
 	byte width     = GB(p1,  8, 8);
 	byte height    = GB(p1, 16, 8);
 	bool adjacent  = HasBit(p1, 24);
 
-	StationClassID spec_class = (StationClassID)GB(p2, 0, 8);
+	StationClassID spec_class = Extract<StationClassID, 0, 8>(p2);
 	byte spec_index           = GB(p2, 8, 8);
 	StationID station_to_join = GB(p2, 16, 16);