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A.-The locomotive brake will release, after any manner of application whatever. In this position of the independent brake-valve of the No. 6 equipment, a warning port is caused to blow, as a measure of safety in case of a broken return-spring, as, if the independent brake-valve should remain in Release Position, it would be impossible to apply the locomotive brake in any manner.
Q. 16.-What is the effect of the Running Position of the independent Brake-Valve Handle ?
A.-It is the regular carrying position for the brakevalve handle, and must not be moved therefrom except to apply the independent locomotive brake, or to release it when the automatic brake-valve handle is in some other than its Running Position. When the automatic brake-valve handle is in Running Position, and a locomotive-brake application has been made by the independent brake-valve, in order to release it it is only necessary to place the independent brake-valve in Running Position. The locomotive brake can not be released by the automatic brake-valve unless the independent brake-valve is in Running Position.
Q. 17.-What is effected in the Lap Position of this brake-valve ?
A.--As in any other brake-valve, all ports in the rotary valve and rotary-valve seat that are separable, are closed; it is the negative position to which the handle
Regulation of Pressures
is returned after making a graduated, independent application.
Q. 18.-Explain the Slow-Application Position.
A.—In this position the locomotive brake will be applied slowly, as the term indicates, giving the engineer the opportunity to graduate the application as finely as he desires. After a graduated application, the handle should be returned to the Lap Position, but when it is required that the locomotive shall be held for some time under the control of the independent brake, leave the handle in this position of Slow Application.
Q. 19.--Explain the Quick-Application Position.
A.—The action of all parts affected during an independent-brake application is no different as between the Slow-Application and Quick-Application Positions, except that in the latter position braking pressure is supplied to the engine- and tender-brake cylinders through a larger port in the rotary valve, giving, as the name implies, a quick action of the locomotive brake.
Q. 20.-What regulates the Brake-Pipe Pressure in the E-T equipment?
A.—The Feed Valve.
Q. 21.-What regulates the Main-Reservoir Pressure ?
A.—The Duplex Pump-Governor.
Q. 22.-What pressure is supplied to the Independent Brake-Valve ? What regulates it at that figure ?
Also, what other air-pressure-using device is supplied from the same source ?
A.—45 pounds pressure is supplied to the independent brake-valve, by the Reducing Valve, which also furnishes the pressure used in the Train Air-Signal System.
Q. 23.-Where does the pressure for the locomotive brake cylinders come directly from, at an automatic application ? At an independent application ?
A.-In both cases, from the main reservoir.
Q. 24.-In each case, what reduces the pressure, and regulates the amount?
A.-At an automatic application, the distributing valve, influenced by the amount of brake-pipe-pressure reduction; at an independent application, by the independent brake-valve, or the reducing valve.
Q. 25.-If we wish to carry 70 pounds brake-pipe pressure, and 90 pounds main-reservoir pressure, with brake-valves in Running Position, but after pumping up to the limit we have pressures of 60 pounds and 90 pounds, respectiveiy; is the pump governor all right? What changes should be made to secure the desired pressures ?
A.-Although 90 pounds is the pressure desired in the main reservoir, the governor is not adjusted correctly. The responsible governor top is not expected to regulate the main-reservoir pressure at 90 pounds,
Changing to High-Speed Pressures
but to regulate that pressure at a figure 20 pounds higher than that in the brake pipe. As the case stands, the regulating spring of the excess-pressure governor top should be slackened until the gauge shows 80 pounds on the Red Hand, as against the 60 pounds on the Black Hand; then, slowly turn the hand-wheel on the feed valve clockwise, tightening the regulating spring, and both gauge hands will rise equidistantly until they stand as desired at 70 pounds brake-pipe, and 90 pounds main-reservoir, pressures.
Q. 26.—With these pressures secured, suppose that you should have to operate a High-Speed-Braked passenger train, what changes would you be required to make in the air-brake equipment?
A.-To change the E-T equipment from the common “70-pound brake” to the High-Speed Brake, is a very simple matter, indeed. When such change may be anticipated, the high-pressure governor top should be permanently adjusted at a figure some higher than 130 pounds—say 140 pounds; also, the high-pressure stop on the feed valve should be already adjusted and tightly clamped in the proper position. To make the change it is only necessary to revolve the wheel handle of the feed valve clockwise until the pin on the wheel strikes the stop situated diametrically opposite the 70-pound stop; brake-pipe and main-reservoir pressures will be equally and automatically advanced by this simple act, to 110
pounds and 130 pounds, respectively, and so maintained while the automatic brake-valve is in Running Position; but when the handle is moved to Lap, or either of the Application Positions, main-reservoir pressure will be increased to 140 pounds, as a measure toward prompt train-brake release.
Q. 27.-If the brake-cylinder Piston Travel becomes excessively long, on the locomotive or tender, will the force on the piston be reduced thereby, as it is in the ordinary automatic brake ?
A.-No; the air pressure per square inch on the pistons will not be affected by variations of the piston travel, and the holding power will be the same for any given degree of application, so long as the piston does not strike the non-pressure (back) head of the brake cylinder; and the pressures per square inch will be equal in the cylinders of the driver, tender, and truck brake. With too long piston-travel, the brake will be tardy in completely releasing, however.
Q. 28.—What will be the effect of Leakage of Locomotive Brake-Cylinder Pressure ?
A.-An amount of brake-cylinder-pressure leakage that could render the ordinary automatic brake absolutely ineffective will not at all weaken the holding power of the E-T brake, for in the latter this pressure is maintained -insured against leakage, or the loss of pressure from leakage.