Queensland PB15 class locomotive

The Queensland Railways PB15 class locomotive was a class of 4-6-0 steam locomotives operated by the Queensland Railways.

History
The design resulted from a need for more powerful engines for passenger trains. The PB15 Class was designed by Locomotive Engineer, Henry Horniblow and LW Piggott. Per Queensland Railway's classification system they were designated the PB15 class, P representing they were a passenger locomotive, the B that they had three driving axles and the 15 the cylinder diameter in inches. The PB15s were in essence identical to the B15 class.

The first PB15 engines were delivered by Walkers Limited, Maryborough in December 1899. By 1912, a total of 202 had been built by Walkers (122), Evans, Anderson, Phelan & Co (70), Kitson & Co (20) and Toowoomba Foundry (20). They were fitted with Stephenson valve gear. In May 1918, no. 411 was converted at North Ipswich Railway Workshops into a tank engine, the one off member of the 6D15 class. In March 1922 however, due to poor performance it was converted back to its original tender form.

In 1924 one example was built by North Ipswich Railway Workshops for the Aramac Shire Tramway. It was acquired by Queensland Railways in 1958.

In 1925/26, Walkers manufactured a further 30 improved PB15 Class locomotives. These were fitted with larger tenders and Walschaerts valve gear. This earned this variant of the PB15 the nickname Walschaerts.

In 1932, a number of PB15 class locomotives attached to Ipswich depot were fitted with a second sandbox for rear sanding to assist with shunting work on the colliery branches. These were nos. 351, 508, 567, 574, 587, 591, and 750, the last mentioned being a Walschaerts or 1924 type PB15. Later, the rear sanding equipment attached to No.591 was removed and PB15 No. 525 was fitted in lieu.

Preservation
Five examples have been preserved:
 * 444 is on display at the Workshops Rail Museum, Ipswich
 * 448 is operational on the Queensland Pioneer Steam Railway, Swanbank and has been named in preservation RV Armstrong after the society's late founding member . It could be 446, but this is wrong.
 * 454 is undergoing a major overhaul at the Bellarine Railway, Queenscliff, Victoria
 * 732 is in storage at the Workshops Rail Museum, one of the 1924 Walschaerts
 * 738 is on display at the Rosewood Railway Museum, Rosewood, one of the 1924 Walschaerts