diff --git a/src/cargotype.h b/src/cargotype.h
index 10aae014d2..c53404d3be 100644
--- a/src/cargotype.h
+++ b/src/cargotype.h
@@ -45,7 +45,7 @@ enum TownProductionEffect : uint8_t {
 };
 
 /** Cargo classes. */
-enum CargoClass {
+enum CargoClass : uint16_t {
 	CC_NOAVAILABLE  = 0,       ///< No cargo class has been specified
 	CC_PASSENGERS   = 1 <<  0, ///< Passengers
 	CC_MAIL         = 1 <<  1, ///< Mail
@@ -60,6 +60,9 @@ enum CargoClass {
 	CC_SPECIAL      = 1 << 15, ///< Special bit used for livery refit tricks instead of normal cargoes.
 };
 
+/** Bitmask of cargo classes. */
+using CargoClasses = uint16_t;
+
 static const uint8_t INVALID_CARGO_BITNUM = 0xFF; ///< Constant representing invalid cargo
 
 static const uint TOWN_PRODUCTION_DIVISOR = 256;
@@ -72,7 +75,7 @@ struct CargoSpec {
 	uint8_t rating_colour;
 	uint8_t weight;                    ///< Weight of a single unit of this cargo type in 1/16 ton (62.5 kg).
 	uint16_t multiplier = 0x100; ///< Capacity multiplier for vehicles. (8 fractional bits)
-	uint16_t classes;                  ///< Classes of this cargo type. @see CargoClass
+	CargoClasses classes; ///< Classes of this cargo type. @see CargoClass
 	int32_t initial_payment;           ///< Initial payment rate before inflation is applied.
 	uint8_t transit_periods[2];
 
diff --git a/src/newgrf.cpp b/src/newgrf.cpp
index 3458535b18..5d4934218e 100644
--- a/src/newgrf.cpp
+++ b/src/newgrf.cpp
@@ -318,8 +318,8 @@ struct GRFTempEngineData {
 		NONEMPTY,       ///< GRF defined the vehicle as refittable. If the refitmask is empty after translation (cargotypes not available), disable the vehicle.
 	};
 
-	uint16_t cargo_allowed;
-	uint16_t cargo_disallowed;
+	CargoClasses cargo_allowed;
+	CargoClasses cargo_disallowed;
 	RailTypeLabel railtypelabel;
 	uint8_t roadtramtype;
 	const GRFFile *defaultcargo_grf; ///< GRF defining the cargo translation table to use if the default cargo is the 'first refittable'.
@@ -9001,8 +9001,8 @@ static void CalculateRefitMasks()
 				static const struct DefaultRefitMasks {
 					uint8_t climate;
 					CargoLabel cargo_label;
-					CargoTypes cargo_allowed;
-					CargoTypes cargo_disallowed;
+					CargoClasses cargo_allowed;
+					CargoClasses cargo_disallowed;
 				} _default_refit_masks[] = {
 					{T | A | S | Y, CT_PASSENGERS, CC_PASSENGERS,               0},
 					{T | A | S    , CT_MAIL,       CC_MAIL,                     0},