Hackworth's "Royal George", 1827.
Hackworth’s 0-6-0 “Royal George”, Stockton & Darlington, 1827
This engine was altered from a Locomotive of the "Puffing Billy" type by Timothy Hackworth and commenced working in October 1827. The boiler was a plain cylinder 13 ft. long and 4 ft. 4 in. in diameter. The return flue of the Wylam engines was adopted and a liberal amount of heating surface thus obtained. There were six coupled wheels 4 feet in diameter, and the cylinders, which were placed vertically at the end opposite to the fire place, were 11" diameter, the stroke of the piston being 20 inches. The piston rods worked downward and were connected to the first pair of wheels. These were without springs, so that the pistons should not jump the wheels up and down, but the middle and back pairs of wheels carried their load through stout springs.
Wescott’s description of the 0-6-0 is as follows: Museum drawing based mainly on contemporary drawings and descriptions. Two inverted vertical cylinders, 11 in. by 20 in., one on each side of and outside the return-flue boiler, drove the same axle directly. The other two axles were mounted on springs and connected to the driving axle by outside coupling rods. Single blast pipe. Weight c. 8.4 tons. Heating surface 141 sq. ft. Wheel base 8 ft. 6 in. Inside horizontal plate frame. Loose eccentric valve gear. Direct loaded spring safety-valve.
The following description is from http://www.railcentre.co.uk/hackworth/royal_george.htm:
The Royal George had a direct drive from the cylinders to the wheels, and it was the first locomotive with three axles coupled by outside coupling rods. It was the first conventionally six-wheel coupled locomotive and as such it was the ancestor of the now famous 0-6-0 British goods engines. With its weight increase of 50% over Stephenson designed locomotives, it had greater adhesion, moreover the even distribution of weight limited the damage to the rails.
The Royal George cost £425, and in 1828 it carried 22,422 tons of coal over 20 miles at a cost of £466 including repairs, maintenance and interest on capital. The same work performed by horses would have cost £998.
Notable engineers of the day were critical of Royal George as being no more than 'a good serviceable engine' and contrary to general belief, it was not the first locomotive to exceed the efficiency of horse haulage. The suggestion was that Hackworth’s locomotives, with their vertical or inclined cylinders were doomed to obsolescence, if only because of their slow operating speed. The criticism by those engineers appears tainted by 'sour grapes' as they completely misunderstood the needs of the Stockton & Darlington Railway, for which Royal George had been designed.
Royal George served the Company well for almost two decades, reliable in service and with its six coupled wheels it gave stability pulling heavy loads in all types of weather. On a line dominated by the haulage of heavy minerals, and the fact that only a single line existed, speed was neither essential or desirable. Indeed, up to 1830, the locomotives supplied by Robert Stephenson & Co. were either unreliable in service or poorly constructed, which is not surprising, considering that their design was based upon experience gained on colliery lines which were short, and subjecting them to long hauls under arduous conditions revealed several defects.
It is recorded that the Committee of the Stockton & Darlington Railway, expressed their satisfaction with the results of the working of Royal George by voting a bonus of £20 to be paid to their engineer. The locomotive continued in service until 26th December 1840, when it was sold to the Wingate Colliery Company for £125 more than its original cost of £425. After several years working it was again re-sold to the Earl of Durham.
The following is from Welford’s Men of Mark Twixt Tyne And Tweed
In this engine, departing from the usual plan of having two upright cylinders working on different shafts, Hackworth inverted his cylinders and, placing them on opposite sides of the boilers applied their connecting rods to actuate the same axle-tree. At the some time, in lieu of the straight flue employed in Blenkinsop's and, Stephenson’s engines, he adopted the return fire-tube which was used by Trevethick and Hedley; and by throwing the escaping steam into the chimney throug a narrow orifice, he greatly augmented the force of the stem blast, and consequently the rapidity of combustion in the furnace. Finally, he placed the engine upon six whees all coupled which yielded an increase of adhesion upon the rails in every state of the weather. The Royal George was "the first of a new type of engine and the nearest approach to the modem locomotive of any that had yet been built.