1 files changed, 1 insertions, 0 deletions
diff --git a/engine.h b/engine.h
index 0e3ee1a1c..64ce15934 100644
--- a/engine.h
+++ b/engine.h
@@ -30,6 +30,7 @@ typedef struct RailVehicleInfo {
 	                    //       kind of visual effect to generate for a vehicle (default, steam, diesel, electric).
 	                    //       Same goes for the callback result, which atm is only used to check if a wagon is powered.
 	byte shorten_factor;	// length on main map for this type is 8 - shorten_factor
+	byte user_def_data; ///! Property 0x25: "User-defined bit mask" Used only for (very few) NewGRF vehicles
 } RailVehicleInfo;
 
 typedef struct ShipVehicleInfo {