398 EXPLANATION OF THE PLATES. 



PLATE LXVII. B . 



THE CYLINDER AND PISTON AT LARGE; STANHOPE AND TYNE RAILWAY 



LOCOMOTIVE ENGINE. 



This plate represents the form, construction, and dimensions of the cylinder and 

 piston of this engine, and fig. 1, Plate LXVII. A., the cylinder cover, to the same scale. 



The steam from the boiler is admitted into the steam-chest A, fig. 1, from the pipe 

 B, and from thence into the cylinders through the steam ports C, by the alternating 

 action of the slide D ; the exhausting pipe is shewn at E. F is the rod to which the 

 brass slide D is attached ; this rod receives the requisite alternating action by means 

 of an eccentric and driver of the usual construction, placed upon the cranked axle of 

 the engine. 



The piston of this engine is represented in vertical section at fig. 2, and in hori- 

 zontal section at fig. 3. The vertical section shews the piston to consist of two me- 

 tallic rings A A, (brass,) the upper one being grooved to receive the tongue of the lower 

 one. These rings are kept forcibly pressed against the cylinder by the split ring 

 (steel) B B, figs. 2 and 3, in addition to which, are four other steel springs C C C C> 

 fig. 3, which may be adjusted to any further degree of tension by the nut-screws 

 D D D D. The piston cover and bottom are brought up by the screws C C, fig. 2, 

 passing through the holes E E E E, fig. 3, tapped for that purpose. The piston-rod 

 is keyed through, as shewn by the space for the keys at D, fig. 2. 



The following scale of dimensions with respect to the diameters of wheels and 

 piston rods may be found useful. 



WHEEL TYERS FOR LOCOMOTIVES, BY ADMEASUREMENT. 



Diameter of Wheels. Circumference. 



Feet. In. Feet. In. In. In. 



50 . . 16 6 by 5 by If 



46 . . 14 9 do. do. 



40 . . 13 2 do. do. 



36 . . 11 8 do. do. 



30 . . 10 2 do. do. 



28 . . 92 do. do. 



26,. 8 7 do. do. 



DIAMETER OF PISTON-RODS IN LOCOMOTIVE ENGINES, AS USED BY 

 MESSRS. ROBERT STEPHENSON AND CO. 



Diameter of Cylinder, in inches. Diameter of Piston-rod, in inches. 



5 '74 



6 '9 



