diff --git a/src/elrail_func.h b/src/elrail_func.h
--- a/src/elrail_func.h
+++ b/src/elrail_func.h
@@ -36,6 +36,6 @@ void DrawRailCatenary(const TileInfo *ti
 void DrawRailCatenaryOnTunnel(const TileInfo *ti);
 void DrawRailCatenaryOnBridge(const TileInfo *ti);
 
-bool SettingsDisableElrail(int32 p1); ///< _settings_game.disable_elrail callback
+void SettingsDisableElrail(int32 new_value); ///< _settings_game.disable_elrail callback
 
 #endif /* ELRAIL_FUNC_H */