diff --git a/src/engine.h b/src/engine.h
--- a/src/engine.h
+++ b/src/engine.h
@@ -9,9 +9,15 @@
 #include "rail.h"
 #include "sound.h"
 
+enum RailVehicleTypes {
+	RAILVEH_SINGLEHEAD,
+	RAILVEH_MULTIHEAD,
+	RAILVEH_WAGON,
+};
+
 typedef struct RailVehicleInfo {
 	byte image_index;
-	byte flags; /* 1=multihead engine, 2=wagon */
+	RailVehicleTypes railveh_type;
 	byte base_cost;
 	RailTypeByte railtype;
 	uint16 max_speed;
@@ -118,11 +124,6 @@ enum {
 };
 
 enum {
-	RVI_MULTIHEAD = 1,
-	RVI_WAGON = 2,
-};
-
-enum {
 	NUM_VEHICLE_TYPES = 6
 };