B15 Class

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".

Cost of Engines when Constructed

* Average price for first 30 constructed