diff --git a/nml/global_constants.py b/nml/global_constants.py
index 964455b..9107665 100644
--- a/nml/global_constants.py
+++ b/nml/global_constants.py
@@ -1216,6 +1216,8 @@ const_list = [
     (named_parameters, param_from_name),
     cargo_numbers,
     railtype_table,
+    roadtype_table,
+    tramtype_table,
     (item_names, item_to_id),
     (settings, setting_from_info),
     (config_flags, config_flag),