Hello Dai. I have never tried wheel pulling, maybe I should give it a go. I have always thought that, with the great majority of locos having inside frames and with the ends of the axles being flush with the outer edge of the wheel boss, pulling the wheels outwards would lead to the wheels not being sufficiently secure on the axles. Therefore, I have assumed that keeping the existing RTR wheels would involve replacing the OO gauge axles with longer ones to suit EM gauge. Am I missing something here?