diff --git a/src/vehicle_base.h b/src/vehicle_base.h
--- a/src/vehicle_base.h
+++ b/src/vehicle_base.h
@@ -46,6 +46,14 @@ enum VehicleFlags {
 	VF_STOP_LOADING,            ///< Don't load anymore during the next load cycle.
 };
 
+/** Bit numbers used to indicate which of the #NewGRFCache values are valid. */
+enum NewGRFCacheValidValues {
+	NCVV_POSITION_CONSIST_LENGTH   = 0, ///< This bit will be set if the NewGRF var 40 currently stored is valid.
+	NCVV_POSITION_SAME_ID_LENGTH   = 1, ///< This bit will be set if the NewGRF var 41 currently stored is valid.
+	NCVV_CONSIST_CARGO_INFORMATION = 2, ///< This bit will be set if the NewGRF var 42 currently stored is valid.
+	NCVV_COMPANY_INFORMATION       = 3, ///< This bit will be set if the NewGRF var 43 currently stored is valid.
+};
+
 /** Cached often queried (NewGRF) values */
 struct NewGRFCache {
 	/* Values calculated when they are requested for the first time after invalidating the NewGRF cache. */