diff --git a/src/depot_type.h b/src/depot_type.h
index d511b1b9e5..8c41857138 100644
--- a/src/depot_type.h
+++ b/src/depot_type.h
@@ -12,10 +12,10 @@
 
 #include "station_type.h"
 
-typedef StationID DepotID; ///< Type for the unique identifier of depots.
+typedef uint16 DepotID; ///< Type for the unique identifier of depots.
 struct Depot;
 
-static const DepotID INVALID_DEPOT = INVALID_STATION;
+static const DepotID INVALID_DEPOT = (DepotID)INVALID_STATION;
 
 static const uint MAX_LENGTH_DEPOT_NAME_CHARS = 32; ///< The maximum length of a depot name in characters including '\0'