Your citation for   Mameda illustrates the problem You merely provided a link to the Japanese Wikipedia page that describes Mameda town  today You did not establish that this reading was used  locally  at the time when the tramway operated and  by the tramway operator It was not uncommon to find localities  and businesses  which used local pronunciations readings of place names This practice has faded but has by no means disappeared in virtual defiance of Tokyobased authorities Kyoto clings to Kyotoben pronunciations of certain wellknown place names Thus  might well have been Mameda It might also have been Mameta This being a Kyushu place name it might also have been Mameden Zuden and Tden are as is said unlikely but not impossible