The bus on the left has to be a 23. Question then is, is it an AR? I think it might be, but I will leave it to Dr. Marie Oneonetwo Cassidy to give a definitive view. ARs were the norm on the 23 from about 1948 to 1960. The photo is probably early 1950s, but maybe a bit earlier. Are they tram tracks still on O'Connell St.? I wonder how long they were there?