No.15 here is a Great Northern Railway J21 class 0-6-0. This class was separated into 'saturated' and 'superheated'-boilered varieties, and this particular model is of one of the 'saturated' engines. After the Grouping in 1923, the newly-formed LNER reclassified them as J1 for the 'saturated' locos, and J2 for the 'superheated' ones (see page 11). Built from Ace Kits components.