diff --git a/nml/actions/action0properties.py b/nml/actions/action0properties.py
--- a/nml/actions/action0properties.py
+++ b/nml/actions/action0properties.py
@@ -816,7 +816,8 @@ properties[0x0A] = {
'min_cargo_distr' : {'size': 1, 'num': 0x14},
'random_sound_effects' : {'custom_function': random_sounds}, # = prop 15
'conflicting_ind_types' : {'custom_function': industry_conflicting_types}, # = prop 16
- 'prob_random' : {'size': 1, 'num': 0x17},
+ 'prob_random' : {'size': 1, 'num': 0x17}, # Obsolete, ambiguous name, use 'prob_map_gen' instead
+ 'prob_map_gen' : {'size': 1, 'num': 0x17},
'prob_in_game' : {'size': 1, 'num': 0x18},
'map_colour' : {'size': 1, 'num': 0x19},
'spec_flags' : {'size': 4, 'num': 0x1A},