The numbering of Trident models can be confusing. This casting carries a number T147 but it is a Trident Alpha model and these models were made by a different modeller to the original Trident models. Models by the new maker were re-numbered by adding 10000 to the T number to avoid confusion with old Trident models which had been made by the original Trident model maker and later on they were re-issued with their original Trident numbers. T147 was the US submarine, Halibut and so Alpino became Ta10147 in the catalogue.