Although they were related chronologically and by design, with my limited knowledge of the GNR I had forgotten that. They outwardly are so dissimilar to the U which lost its tanks, was shortened then lengthened by the addition of a tender. The T1/T2s never received the beautiful sky blue livery of the express passengers locos, being confined to shorter suburban workings for the most part. In terms of era they contemporaries of the U class, whereas the UGs did not appear for 2 decades after the U class.
Lovely model, Patrick!