Notes

These were the largest non superheated six coupled engines to operate in the state. The class was introduced when it was proposed to increase the size of the Sydney Mail (via Wallangarra). They were originally used for this train and mail trains between Brisbane and Rockhampton. By 1930s, with the availability of superheated engines they were relegated to lesser duties. Four engines were attached to the Central Division during World War 2 and they worked as far north as Bowen. Upsurge of traffic during those hostilities caused them to again be pressed into heavy main line passenger work. In their final years they were restricted to slow goods and shunting trains. Like many saturated engines, they were heavy on coal and water. They were generally unpopular with crews particularly with poorer coals and heavy loads. Superheating was trialled on two engines, N°678 and N°610, in 1917 but proved unsuccessful, apparently due to problems lubricating the slide valves. Superheaters were removed when the engines were reboilered between 1929 and 1931. The class contained a number of unusual features. The safety valves were contained in a small dome mounted behind the large regulator dome. There was a large gap between the second and third sets of coupled wheels. One standard Sellers injector was fitted on the fireman’s side whilst the other was a Davies and Metcalfe combined injector and clack valve mounted on the boiler back plate. They were the first engines to be fitted with what became the standard QR whistle for the next 35 years. Scrapping of the class commenced in 1950 and the last two engines in service, N°689 and N°690, were written off in November 1960.

Notes

* Six engines were obtained from Chillagoe Railway and Mining Coy after its collapse. These engines were designed to provide an engine more powerful than the B13 class. A number of different features were introduced to various batches of this class. The first fifteen engines built by Nasmyth-Wilson had British style “pull over” regulators, separate regulator and safety valve domes on the boiler and spartan cabs but no air brakes. The second batch of engines, constructed by Evans Anderson Phelan, were fitted with an enclosed cab with glass windows on the spectacle plate, American style “pull out” regulator and Westinghouse Brakes. These engines also had steel boilers in place Yorkshire iron used on the earlier batch. This allowed the boiler pressure to be raised to 140 psi. Further improvements were made to the cab on the engines built by Yorkshire Engine Company in 1895. This design of cab became standard on all subsequent engines until the “sedan” cab was introduced in 1935. American Balance slide valves were fitted to all B15 engines built from 1898. The “balanced” valves proved successful and were fitted to all subsequent slide valve engines.

The modifications introduced with various batches were later incorporated into the older engines as they underwent overhaul. The large awing in front of the spectacle plate of earlier cabs disappeared when the new style cabs were fitted. Sand boxes were originally on the running boards but later replaced with the more common sandbox mounted on top of the boiler. As boilers were renewed the safety valves were incorporated into the regulator dome. In 1900, N° 336 was fitted with 45″ coupled wheels to increase the engines speed and so make it suitable for use on passenger trains. The experiment was successful and a further 92 engines were similarly rebuilt. They became known as the “B15 Converted” class to distinguish them from the original designed engines. The five engines that did not undergo conversion were all condemned in 1934. This class was sometimes referred to as “B15 Goods”.

* Average price for first 30 constructed

Abbreviations

NW – Nasmyth, Wilson & Co, Manchester, UK
EAP – Evans, Anderson, Phelan & Co, Brisbane, Qld
York – The Yorkshire Engine Co, UK
Walkers – Walkers Ltd, Engineers, Maryborough, Qld
WO – Written off Register