1, 2, 3, Rings arranged telescopically, forming barrel of boiler. 4, Solid angle-iron ring. 5, Tube plate. 6, Smoke box. 7, Shell, or covering plate. 8, Foundation ring. 9, Throat plate. 10, Back plate. 11, Fire door. 12, Covering plate of inside fire-box. 13, Tube plate. 14, Back plate. 15, Stays. 16, Mouth-piece. 17, Stays from inside fire-box to shell plate. 18, Palm stays. 19, Tubes. 20, Smoke-box door. 21, Pinching screw. 22, Chimney. 23, Chimney cap. 24, Blast pipe. 25, Top of blast pipe. 26, Balance weight. 27, Wheel spokes. 28, Front buffer. 29, Mud plug. 30, Safety valve. 31, Safety lever. 32, Spring balance. 33, Whistle. 34, Dome. 35, Regulator. 36, Steam pipes. 37, Elbow pipe. 38, Brick arch. 39, Fire bars. 40, Ash pan. 41, Front damper. 42, Back damper. 43, Frame plate. 44, Iron buffer beam (front). 45, Iron buffer beam (back). 46, (See half width plan) cylinder. 47, Cylinder posts, valve. 48, Valve chest. 49, Steel motion plate. 50, Horn blocks. 51, Axle boxes. 52, Slide bars. 53, Connecting rod. 54, Crank shaft. 55, Crank shaft, big end of. 56, Crank shaft, arm of. 57, Expansion link. 58, Weigh-bar shaft. 59, Valve spindle. 60, Valve rod guide. (See half width plan). 61, Pump. 62, Delivery pipe. 63, Field pipe. 64, Exhaust pipe. 65, Volute spring. 66, Draw-bar hook. 67, Lamp iron. 68, Oil cup. 69, Oil pipes. 70, Cab. 71, Regulator handle. 72, Reversing lever. 73, Draw-bar. 74, Draw-pin. 75, Steam-brake cylinder. 76, Hand-brake. 77, Sand-rod. 78, Front damper. 79, Back damper. 80, Trailing wheel. 81, Driving wheel. 82, Leading wheel. 83, Spring. 84, Hand rail. 85, Brake blocks. 86, Waste water-cocks. 87, Life guard. 88, Railing axle. 89, Leading axle. Z, Lead plug. 43, Frame plate from end to end of engine. 44, Iron buffer-beam. 46, Cylinders. 50, Horn block, to carry axle-box and brass. 51, Axle-box and brass. 52, Slide bars. 53, Connecting-rod. 54, Driving axle. 55, Big end of driving axle. 56, Arm of driving axle. 59, Valve-spindle. 60, Valve-rod guide. 61, Pump. 76, Hand brake. 85, Brake blocks. 88, Trailing axle. 89, Leading axle. 90, Piston rod. 91, Piston head, held on the rod by a brass nut. 92, Backway eccentric rod. 93, Frontway eccentric rod. 94, Eccentric Straps. 95, Eccentric sheaves. 96, Tire. 97, Lip on tire. 98, Brake irons. 99, Foot plating. 100, Transverse stay. A, Water space between inside and outside fire boxes. B, Slide-block with end of pump-ram screwed into the end. C, Link motion (see 57, inside view). D, Slide valve rod, working guide. H, Inside journal, showing how the axle is supported inside of frame plates. I, Cross-head, solid, with piston rod. [Illustration: UNDERNEATH THE LOCOMOTIVE--HALF WIDTH PLAN.] 15, stays in walls of fire-boxes. 18, stays from crown plate to covering plate. 19, tubes. 23, smoke-stack. 40, ash-pan. 54, crank shaft. 55, big end of crank-shaft. 56, arm of big end. 34, dome. [Illustration: IN FRONT OF THE LOCOMOTIVE CROSS-SECTION.]