diff --git a/newgrf_callbacks.h b/newgrf_callbacks.h
--- a/newgrf_callbacks.h
+++ b/newgrf_callbacks.h
@@ -6,33 +6,44 @@
 /** @file newgrf_callbacks.h
  */
 
-// This enum lists the implemented callbacks
-// Use as argument for the GetCallBackResult function (see comments there)
+/**
+ * List of implemented NewGRF callbacks.
+ * Names are formatted as CBID_<CLASS>_<CALLBACK>
+ */
 enum CallbackID {
 	// Powered wagons, if the result is lower as 0x40 then the wagon is powered
 	// TODO: interpret the rest of the result, aka "visual effects"
-	CBID_WAGON_POWER = 0x10,
+	CBID_TRAIN_WAGON_POWER          = 0x10,
 
 	// Vehicle length, returns the amount of 1/8's the vehicle is shorter
 	// only for train vehicles
-	CBID_VEH_LENGTH = 0x11,
+	CBID_TRAIN_VEHICLE_LENGTH       = 0x11,
 
 	// Refit capacity, the passed vehicle needs to have its ->cargo_type set to
 	// the cargo we are refitting to, returns the new cargo capacity
-	CBID_REFIT_CAP = 0x15,
+	CBID_VEHICLE_REFIT_CAPACITY     = 0x15,
 
-	CBID_ARTIC_ENGINE = 0x16,
+	CBID_TRAIN_ARTIC_ENGINE         = 0x16,
 };
 
-// bit positions for rvi->callbackmask, indicates which callbacks are used by an engine
-// (some callbacks are always used, and dont appear here)
-enum CallbackMask {
-	CBM_WAGON_POWER = 0,
-	CBM_VEH_LENGTH = 1,
-	CBM_REFIT_CAP = 3,
-	CBM_ARTIC_ENGINE = 4,
+/**
+ * Callback masks for vehicles, indicates which callbacks are used by a vehicle.
+ * Some callbacks are always used and don't have a mask.
+ */
+enum VehicleCallbackMask {
+	CBM_WAGON_POWER    = 0, ///< Powered wagons (trains only)
+	CBM_VEHICLE_LENGTH = 1, ///< Vehicle length (trains only)
+	CBM_LOAD_AMOUNT    = 2, ///< Load amount
+	CBM_REFIT_CAPACITY = 3, ///< Cargo capacity after refit
+	CBM_ARTIC_ENGINE   = 4, ///< Add articulated engines (trains only)
+	CBM_CARGO_SUFFIX   = 5, ///< Show suffix after cargo name
+	CBM_COLOUR_REMAP   = 6, ///< Change colour mapping of vehicle
+	CBM_SOUND_EFFECT   = 7, ///< Vehicle uses custom sound effects
 };
 
+/**
+ * Result of a failed callback.
+ */
 enum {
 	CALLBACK_FAILED = 0xFFFF
 };