FIG. 19.-No. 6 Distributing Valve with Quick-Action Cylinder Copyright, 1909, by The Norman W. Henley Publishing Co. been for the purpose of affording brake-cylinder pressure connection with the quick-action cylinder cap in the possible case of its use; passage m opens into the lower chamber under the rubber-seated, emergency check-valve 53, the check-valve being held to its seat in the absence of brake-cylinder pressure by the spring, 54. The intermediate chamber, x, is closed against either brake-pipe pressure or brake-cylinder air, now, and is therefore given no reference color. At graduated service applications, equalizing piston 26 moves only to contact with graduating stem 59, without compressing the graduating spring or moving the emergency slide-valve, and the brake-cylinder pressure can only fill the check-valve chamber of the cylinder cap; so that no unusual results are obtained, except from emergency applications. Emergency Position. Fig. 19 represents the distributing valve with quickaction cylinder cap in emergency position. When a sudden, heavy reduction of brake-pipe pressure is made, the effect on the equalizing and application portions of the distributing valve is precisely the same as was described with reference to Fig. 12 B, emergency position; but the full stroke of the equalizing piston, compressing the graduating spring in the quick-action cylinder cap, carries emergency slide-valve 48 with it and uncovers The E-T Air-Brake Pocket-Book port j in the slide-valve seat; brake-pipe air from chamber p rushing down through port j fills chamber x where its pressure unseats the emergency checkvalve, 53, and flows to the passage, m, thence to passage c and the locomotive brake-cylinders through the pipe connecting at CYLS. This described action takes place at the instant piston 26 strikes the quick-action cylinder-cap gasket, and, as main-reservoir air can not flow to the brake cylinders until as the result of piston 26's stroke-pressurechamber air has filled application cylinder g and forced piston 10 to the right to unseat application valve 5— it is obvious that brake-pipe pressure is the first to reach the brake cylinders; with the opening of the application valve the supplying pressures commingle in passage c as brake-cylinder air, which, when it becomes equal to the lowering pressure of the brake pipe, will permit check valve 53 to seat and prevent the brakecylinder air from flowing back to the brake pipe through the open port, j; and, as soon as the brake-cylinder pressure becomes as great as the pressure in the application cylinder, piston 10 will close application valve 5, this upper portion assuming the lap position in the same manner that has been described repeatedly before. Results from the quick-action cylinder cap produce no effect in the rest of the locomotive-brake equipment to differ from the action where the plain cylinder cap is used; merely, in the former case there is a more rapid reduction of brake-pipe pressure, and a consequent economy in the use of main-reservoir pressure. A piping diagram to accompany Fig. 19 would be exactly the same in outline and reference colors as Fig. 12 A. In the case of quick-action triple valves, the vent of brake-pipe air at emergency applications will give a higher brake-cylinder pressure than can be obtained by a full, service application, and it may be imagined that because the No. 6 distributing valve gives a higher brake-cylinder pressure at an emergency than at a full, service application, that this, also, is due to the air received from the brake pipe; such is not the case, however, as the same difference in pressures is obtained with the use of the plain cylinder cap; and the reason for the increased pressure at emergency was explained in connection with Figs. 12 A and 12 B-before the quick-action attachment to the distributing valve was taken up. Regardless of from how many sources the brake-cylinder pressure is obtained, it can not become greater than the pressure in the application cylinder, and when it approaches an excess over that, the exhaust valve (16) will reduce it to an equalization with the application-cylinder pressure. Service brake-pipe reductions of 25 pounds or more will cause the equalizing portion of the distributing |