Our engine-wright had, however, many obstacles to encounter before he could get fairly to work upon the erection of his locomotive. His chief difficulty was in finding workmen sufficiently skilled in mechanics and in the use of tools to follow his instructions, and embody his designs in a practical shape. The tools then in use about the colliery were rude and clumsy, and there were no such facilities, as now exist, for turning out machinery of any entirely new character. Stephenson was under the necessity of working with such men and tools as were at his command, and he had in a great measure to train and instruct the workmen himself. The new engine was built in the workshops at the West Morr, the leading mechanic being John Thirlwall, the colliery blacksmith,--an excellent mechanic in his way, though quite new to the work now intrusted to him. In this first locomotive, constructed at Killingworth, Stephenson to some extent followed the plan of Blenkinsop's engine. The wrought-iron boiler was cylindrical, eight feet in length and thirty-four inches in diameter, with an internal flue-tube twenty inches wide passing through it. The engine had two vertical cylinders, of eight inches diameter and two feet stroke, let into the boiler, which worked the propelling gear with cross-heads and connecting-rods. The power of the two cylinders was combined by means of spur-wheels, which communicated the motive power to the wheels supporting the engine on the rail. The engine thus worked upon what is termed the second motion. The chimney was of wrought-iron, round which was a chamber extending back to the feed-pumps, for the purpose of heating the water previous to its injection into the boiler. The engine had no springs, and was mounted on a wooden frame supported on four wheels. In order to neutralize as much as possible the jolts and shocks which such an engine would necessarily encounter, from the obstacles and inequalities of the then very imperfect plate-way, the water-barrel, which served for a tender, was fixed to the end of a lever and weighted; the other end of the lever being connected with the frame of the locomotive carriage. By this means the weight of the two was more equally distributed, though the contrivance did not by any means compensate for the total absence of springs. The wheels of the locomotive were all smooth, Stephenson having satisfied himself by experiment that the adhesion between the wheels of a loaded engine and the rail would be sufficient for the purposes of traction.[17]