diff --git a/newgrf_engine.h b/newgrf_engine.h
--- a/newgrf_engine.h
+++ b/newgrf_engine.h
@@ -6,37 +6,6 @@
 /** @file newgrf_engine.h
  */
 
-// This enum lists the implemented callbacks
-// Use as argument for the GetCallBackResult function (see comments there)
-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,
-
-	// Vehicle length, returns the amount of 1/8's the vehicle is shorter
-	// only for train vehicles
-	CBID_VEH_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_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,
-};
-
-enum {
-	CALLBACK_FAILED = 0xFFFF
-};
-
 VARDEF const uint32 _default_refitmasks[NUM_VEHICLE_TYPES];
 VARDEF const CargoID _global_cargo_id[NUM_LANDSCAPE][NUM_CARGO];
 VARDEF const uint32 _landscape_global_cargo_mask[NUM_LANDSCAPE];