THE QUARRY HUNSLET DYNASTY
PART 1
Today, Quarry Hunslet 0-4-0STs can be found at narrow gauge venues in Wales and England, and while the type has become a byword for the slate industry which in its heyday saw Snowdonia ‘roof the world’, their differences – both subtle and apparent – tell a fascinating story of British locomotive evolution. The recent publication by Statfold Barn of the book Hunslet Slate Quarry Locomotives: Drawings and Photographs From the Hunslet Archive is an important landmark in narrow gauge research. However, the significant milestones of the dynasty are further considered here.
The early years of narrow gauge steam locomotive evolution were marked by a variety of designs for 2ft 6in gauge and under, including 0-4-0 and 0-4-2 types from Vulcan Foundry in 1845-6, the design characteristics of which are unknown; 0-4-0STs for Crewe Works (full-length inside frames; cylindrical firebox); an 0-4-0ST, later 0-4-2ST and an 0-4-0WT for the Talyllyn Railway (fulllength inside frames; restricted width firebox) and 0-4-0T and 0-4-0ST types for the Festiniog Railway and Festiniog & Blaenau Railway 0-4-2STs with leading inside frames terminating at the throatplate, thereby imparting the tractive stresses to the firebox. One solution was to use full-length one-piece outside mainframes. Two early narrow gauge designs produced by Isaac Watt Boulton during the early 1860s adopted this approach but both were geared. In 1863, Neilson produced a 2ft 6in gauge 0-4-0ST full-length outside-framed design (Nos. 979-81) for the Gaekwar’s Baroda State Railway in India, but its firebox width was constrained by the wheelset ‘back-to-back’ limits.
The breakthrough came when a 1ft 10¾in gauge direct-drive outside-cylinder 0-4-0ST locomotive, No. 51 of 1870 Dinorwic with onepiece outside mainframes and firebox totally behind the trailing wheelset, was constructed for use on the ‘Bottom (Mills) Tramroad’ of the Dinorwic Slate Quarries by Hunslet Engine Co of Leeds.
Certain features of Dinorwic’s design owed much to Manning Wardle practice, notably the domeless boiler barrel with steam collection being accomplished by means of a sharplyraised inverted U-shape firebox wrapper.
Other Manning Wardle features included the tank profile, found on some of
