b15

On 13 January 1897, Walkers Limited completed their first steam locomotive, with a very successful trial run to Howard and return. This engine became known as a B15 class 4-6-0 tender design, and allocated QR No. 299, Walkers Limited works No. 1. The 'B' signifies three driving axles and the '15' is the cylinder diameter in inches. The Walkers Limited design was similar to that of locomotives imported from England, but they were fitted with much-improved cabs and were the first engines built for the Queensland Railways to come ready fitted with the Westinghouse automatic brake system. Builders plates were fitted to each side of the tender as well as each cab side, and in addition, a large circular maker's plate (complete with 5 point star and the words 'Walkers Limited Engineers') was carried on the smokebox door similar to early American engines. Source: maryboroughwhistlestop.org.au/299.html

The Queensland Railways B15 class locomotive is an old class of 4-6-0 engines operated by the Queensland Railways. In 1889 the first B15 class locomotives built by Nasmyth, Wilson & Co entered service. Further orders from Evans, Anderson, Phelan & Co, Yorkshire Engine Company, and Walkers Limited saw the class total of 92 engines by 1899. Per Queensland Railway's classification system they were designated the B15 class engine, B representing they had three driving axles, and 15-inch (381 mm) diameter cylinders. A further six engines were acquired In 1919 when the Queensland Railways took over the Chillagoe Railway & Mining Co.[1][2][3] Problems with broken rails saw three sets of 45-inch (1,143 mm) driving wheels acquired from the South Australian Railways and fitted to 336 at North Ipswich Railway Workshops in November 1900. Judged a success, most others were fitted over the next 30 years. They spent most of their life operating out of Cairns. Source: en.wikipedia.org/wiki/Queensland_B15_class_locomotive

Boeing's bomber development was about fifteen years ahead of their fighters in those days!