If as you wrote the most practical solution and the one upon which there is more consensus is to include a system in the list when 1 Both LRTA and UITP list it as a metro 2 There is no other conflicting source listing it as a light metro then we should add Catania metro in the list It would be discriminating not to do so The User AndreaTartaglia posted a link providing proof that UITP includes it in their list Moreover as the User 93 57 250 62 pointed out I reckon that there is a slight semantic misunderstanding about the the criterion of high passenger capacity The word capacity denotes how much a system can carry not how much it actually carries at the moment i e it relates to the capacity of the infrastructure which Catania s metro indeed has