the 'Sydney Mail' train at Spring Bluff near Toowoomba, circa 1910

From the look of it, a PB15 4-6-0 in front. In those days the break of gauge meant this consist only made it to the Qld/NSW border at Wallangara where it was 'all change' to the other platform to continue into NSW.  Spring Bluff station still exists and in fact is one of the most beautified in Australia, see here