Rhymney Railway P class

Rhymney Railway
P, P1 and AP classes

'P' 0-6-2T No. 75 at Neath General 14 September 1946.

Type and origin Power type Steam Designer C. T. Hurry Riches Builder Robert Stephenson & Co. (3), Hudswell Clarke (5) Build date 1909–1921 Total produced 8

Specifications Configuration 0-6-2T UIC class C1 Gauge 4 ft 8 1⁄2 in (1,435 mm) standard gauge Driver dia. 5 ft 0 in (1.524 m) Loco weight P class, 58.95 long tons (66.02 short tons; 59.90 t) AP class, 63 long tons (71 short tons; 64 t) Fuel type Coal Boiler pressure 175 psi (1.21 MPa) Cylinders Two, inside Cylinder size P: 18 in × 26 in (457 mm × 660 mm) AP: 18.5 in × 26 in (470 mm × 660 mm)

Performance figures Tractive effort P: 20,885 lbf (92.90 kN) AP: 22,060 lbf (98.1 kN)

Career Operators RR • GWR • BR Power class GWR/BR: 3P Withdrawn P: 1954–1955 P1: 1950–1953 AP: 1954–1955

The Rhymney Railway P class was a class of 0-6-2T steam locomotive introduced into traffic in 1909 designed by the Rhymney Railway's engineer C. T. Hurry Riches. These were substantial sized tank locomotives, weighed 60 long tons (67.2 short tons; 61.0 t) (59 long tons or 66.1 short tons or 59.9 t after rebuilding) and were 35 feet 0 inches (10.67 m) in length.

There were initially three locos in the class augmented by another in 1917. The first batch were built by Robert Stephenson and Company but the last by Hudswell Clarke. The last differed in having a Belpaire firebox and was classed as P1. Four more were built by Hudswell Clarke in 1921 just before the company was absorbed by the GWR. These had superheaters and larger cylinders and were classified AP. The Rhymney subsequently rebuilt one of the P class, No. 5, to P1 class.

The P/P1 classes and preceding 1904 introduced M and 1910 A and R classes were closely related designs ideally suited to hauling trains a relatively short distance. The P's were specifically designed for passenger work having larger driving wheels of 5 ft 0 in (1,524 mm) diameter.

All four were reboilered by the GWR with the number 10 boiler from 1926 onwards and in this form was visually similar to the GWR 5600 Class apart from the larger wheels.

Thus the P's (as opposed to the related "Stephenson" M class, R and A classes) were designed for passenger work on the Rhymney Railway, replacing smaller locomotives. When the smaller railway companies were forcibly merged into the GWR these modern 0-6-2's were in generally good order (some were a few months old) and had proved successful. Collectively they became the blueprint for the 200 strong 5600 class.

The design of the 5600 class followed the Rhymney designs quite closely but adopted GWR practice as far as possible, by utilising many standardized parts. Included in Collett’s innovations was a standard number 2 boiler which was suitable for the 5600 (and the M and R class Rhymney locomotives), complete with the traditional copper GWR safety valve casing and copper-capped chimney. A and P classes were rebuilt but used the slightly shorter standard number 10 boiler, also to good effect.