be centred and secured in the prescribed way, and you can then proceed—on one side. Q. 8. In these cases of failure of certain parts of the gear such as the eccentric rod or union link, etc., what are the advantages in being able to still secure the short movement of the valve and a limited port opening when the piston is at the beginning of its stroke? A.—On the big up-to-date engines it is impractical to try to remove the main rod in cases of breakdowns, and when it is left up and the valve is blocked at the centre of its travel, the piston will meet with high resistance toward the finish of either stroke, on account of the air compression ahead of the piston and a partial vacuum behind it; this added to the braking power at applications of the air brake may cause the drivers to slide and flatten. The port opening provided as referred to, gives relief from this effect; further, it permits oil from the lubricator to reach the cylinder and prevent the walls from becoming dry and being cut by the piston-a condition that must be particularly guarded against when the main rod is left up, in cases of breakdowns. INDEX A ACCESSIBILITY of Walschaert gear, 131, 132 Adaptability of Walschaert valve gear, 142, 143 Adjustment of Walschaert valve gear, 102 Advantages derived from the use of Walschaert gear, 129–148 B BAKER-PILLIOD improved valve gear, 228 Advantages in securing the short travel of the valve on Combination lever, if broken short, how arrange, 235 Engine disabled on one side, how to block the valve, 233 Baker-Pilliod valve gear, 222 to 236 inclusive Original style with outside admission, 224 With inside admission, 228 Baldwin engine with Walschaert gear, 65 to 67 inclusive Belgian engine with Walschaert valve motion, 80 to 87 inclusive "Blocking the valve”—what is meant, and how it is done, 171 Breakage of lower section of combination lever, or its link to the Break-downs on the road. Difference in methods of disconnec- tion of Walschaert and Stephenson gears, 170, 171 Broken radius-rod hanger, 178, 179 Broken valve-stem, 179, 180 Building up the Walschaert gear: The start, 28 Built-up Walschaert gear complete, 42 C CASE of broken or detached piston-what to do, 182 Combination lever (lap and lead lever) for inside admission valves, Combination lever (lap and lead lever)-to determine proper Comparative weights of Walschaert and Stephenson valve gears, Confusing in the meaning of lead, 158 Connections of the eccentric rod, 43 Constant lead with reverse lever in any notch, 38 Continuing the layout of the gear, and formulas, 105 to 109 Correcting the built-up motion, 40, 41 Correction of one error introducing others, and their relief, 167 “Cut-off,” meaning of, 160 D DE GLEHN compound engine with Walschaert gear, 67 to 69 Derivation of lead through the Walschaert combination lever, Designing and erecting the Walschaert valve gear, 95–126 104, 105 Details of the Walschaert link, 44 to 49 inclusive Difference between Walschaert and Stephenson motions, 151, 152 Different methods of erection, 49 to 51 inclusive Directness of Walschaert motion, 138, 139 Direct valve motion, 20 Disconnection of radius rod. Method of doing it, 176, 177 Does the radius rod give motion to the valve, with reverse lever Does the rise and fall of the engine on springs affect the valve's E ECCENTRIC rod broken. How to proceed, 179 Eccentric-rod connections, 43 Eccentric rod, testing for length of, 192 to 194 inclusive Effect of valve advance to secure lead, 25 Engine standing as last mentioned, if valve is not exactly cen- Enumerating the chief advantages of Walschaert gear, 129 to Equalized cut-off, Walschaert vs. Stephenson gear, 161, 162 Erecting and designing the Walschaert valve gear, 95-126 Erection, different methods of, 49-51 Evolution of valve motion, II F FORMULAS for lay-out of the gear, 105-109 GEAR, reversing, 37-39 G General effects of lead, 143-148 General notes for adjusting Walschaert valve gear, 111 to 113 H HACKWORTH Valve gear, 198 to 204 inclusive Heating of driving-boxes prevented by adoption of Walschaert Heaviest engine, and fastest engine, have Walschaert gear, 67 Heaviest switching engine (decapod) with Walschaert gear, 75 Broken combination lever, how to provide for getting along Chart showing valve events, 215 Compression-valve rod, breakage of, 217 Cylinders and valves, 204 to 212 Eccentric rod or eccentric crank failure, how to overcome If radius bar fails, what to do, 222 Main valve-rod, breakage of, 217 Questions and answers on break-downs, 217 to 222 Reach rod, reach-rod arm, or reverse shaft, if broken what Reverse link or reverse arm, what to do if broken, 218 |