The Westinghouse Air Brake.

Answers by F. B. Farmer.

149. Fitting Pump Packing Rings.-"In answer to question 144 in the March number, you say that in fitting pump packing rings the piston grooves should be trued up to the rings. Do you mean to file them until the rings will fit?"-P. R.

Answer.-No; the piston grooves should not be filed for the reason that the good fit of rings in grooves, which is necessary to obtain satisfactory results, can not thus be obtained.

The best method in making such repairs is to have the piston grooves trued up to the rings in a lathe. If this is not possible, then file the rings to the grooves, but leave one machined side on each ring. In applying the rings to the piston place the machined side of each away from the piston face the ring is nearest to. This will insure one ring having a true groove bearing for either up or down stroke of the pump.

This method, fitting the rings instead of truing up the grooves, generally, if not always, has another undesirable feature. As rings wear thin they bear on less of the groove faces, leaving a shoulder on the surfaces covered by the new rings when they are entered flush with the piston. As it is necessary that they may be able to enter the grooves to this point without binding, the rings will have to be filed a little thinner at the inner edge than over the remainder of the groove bearing. As will be seen, this necessitates a little filing on the side otherwise to be left as it came from the machine, presuming the faces left by the parting tool were given a finishing cut, as should be done.

The longest and best service is obtained by truing the grooves to the rings, using a lathe.

150. Pump Governor Leakage.-" Referring

to the answer to 147 on page 417 of April, you say that the vent port in the pump governor should be the standard size so as the pump will not have to do more work than it should. Please say whether a leaky ring in the governor piston will not waste air and make the pump work faster. Also, tell how to test for leakage past the ring so as to tell it from steam leakage. Both come out at the same opening."-X.

Answer. Yes, leakage past the gov ernor piston ring will have the same effect as an enlarged vent port. Test for such leakage as follows:

Pump up the pressure until the governor acts, take off the governor check nut, open the pump drain cocks, close the throttle as tight as possible, quickly unscrew the governor regulating nut one turn, or a little more, and then note whether there is any discharge at the governor waste opening. Unless the pump throttle is leaking badly, and the stem of the governor steam valve is a very loose fit, all discharge at the waste opening will be that of air which has leaked past the governor piston packing ring.

All modern governors have the vent port, and with such it is desirable to have the least possible leakage past the ring.

Be sure to proceed in the order given, when making this test, and after it is completed readjust the governor. The purpose in slacking up on the regulating nut is to insure a strong flow of air to the governor piston for a sufficient time to determine the leakage past it.

151. Air Gauge Test.-"How often should the air gauge be tested, and how should it be done?"-R. A. K.

Answer. There are two air gauge tests which should be made regularly. The easier of the two is the one which the engineer should make every trip. It consists of placing the brake valve handle in full release position, when no car brakes are connected, and noting whether the two gauge hands indicate the same pressure, as they will if correct. If they do not, then one or both are wrong. The main reservoir hand is the one most liable to be right. If they stand over three pounds apart the gauge should be reported.

While, as a general rule, the gauge will he found correct when the hands indicate the same pressure with the brake valve handle in full release, yet this is not always so. This fact and the other re

grettable one that all engineers do not

regularly make the foregoinig test and report errors that it indicates, renders it very desirable that all gauges be tested every thirty days by connecting to the train pipe a gauge known to be correct and comparing it with the engine air gauge, first with the brake valve handle in running position and then in full release.

The common method of connecting this test gauge is by means of the hose coup

ling at the rear of the tender, a similar one or a special fitting being attached to the test gauge. The special fitting referred to is one having two adjustments so the test gauge can be coupled to the signal hose for the purpose of determining the regulation of the signal reducing valve and, by means of a little vent which can be opened when desired, the operation of both reducing and signal valves; also, the action of the whistle.

It is best to test the air gauge in place as it sometimes happens that a gauge correct when off the engine is not so when in use. It is important that the test gauge be vertical-that is, as it would stand on a locomotive or when it is be

ing tested when the comparison is being made. Otherwise it may not indicate correctly.

The New York Air Brake.

Answers by J. P. Kelly.

136. Brake Valve Blowing in Release Position. -"What is the matter with a New York engineer's brake valve when it blows in full release position, at the exhaust port, but stops blowing when the handle is moved to running position?"-J. A. S.

Answer. When the handle is in release position no air should escape at the exhaust port C if the vent valve 180, on the end of piston 104-A, and the main slide valve 114-A are tight.

As port O is open to the atmosphere, through cavity P and exhaust port C, when the handle is in running position, the fact that the blow ceases proves that vent valve 180 is tight, and that main slide valve 114-A is leaking.

A leak of this kind is due to the fact that the face of slide valve 114-A has a groove worn in it by the small cut-off valve 110, which, in running position, allows air to blow over the bridge in the seat, from the train pipe, into exhaust passage C, and thence to the atmosphere.

137. Rebound of Piston in Duplex Air Pump. "When my duplex pump is working rather fast I notice a rebound, for a short distance, of the low pressure piston. Can you throw any light on the cause?"H. A. H.

Answer. When the pistons rebound at the end of their strokes, it will usually be found that there is considerable gum in the ports and air passages, which permits a high terminal pressure to be accumu. lated in the end of the air cylinder that can not be readily discharged through the gummed ports, and that, in consequence of this inability to escape, reacts on the

air piston, causing it to "rebound," or move back quickly a short distance. A leaky intermediate discharge valve will also cause the piston to rebound, and this is most likely to be the cause of rebound of piston.

138. Brake Setting When Sand Blowers and Air Bell Ringers are Used.-"Why is it that the brakes will creep on once in a while when the sand blower is used?"”—J. J. O'B.

Answer. Possibly because the sand blower and bell ringers use air faster than the pump can furnish it; but probably it is because the governor is sluggish in its action, and does not permit the pump to start to work so promptly as it should, after shutting off steam from the pump,

and thus the sand blower is able to reduce train pipe pressure, along with main reservoir pressure, sufficiently to set the brakes. A leaky train pipe in addition to the above would aggravate the trouble considerably; and so would a sticky excess pressure valve, provided the handle of the brake valve was in running position at the time the sand blower was used.

139. Spring in Packing Rings.-"What is meant by 'spring' in a packing ring?"— C. S. H.

Answer. The spring in a packing ring is the amount of resistance which the free ends offer to being compressed, while being put into their respective cylinders, and may be judged somewhat by the distance the ends of the ring stand apart when out of the cylinder.

Packing rings are used to make movable air tight and steam tight joints; and in cases where it is desirable that the friction of the moving piston be reduced to a minimum while at the same time it be entirely free from leakage, as is the case with triple pistons, the amount of spring which the packing ring has is an important consideration.

It is the "spring" which keeps the ring out against the wall of its cylinder as the latter, and the ring itself, wears away.

140. Proper Time to Move Handle of Brake Valve to Running Position.-"In order to get excess pressure in the main reservoir, the handle of the brake valve must be carried in running position, and sometimes when the handle is moved to this position from release the brakes apply on the engine and tender.

"Isn't there a way for manipulating the brake valve so as to carry the handle in running position without setting the brakes?"-H. E. T.

Answer.-Excess pressure is necessary to release brakes promptly, and to re

the stem as the lever is being moved. If set with the same lead for both motions you can see that it would be impossible to cover the ports. Try it.

Train Rules and Train Practice.

Answers by H. A. Dalby.

87. Form F.-"There seems to be an inconsistency in the form of train orders under Form F, which reads 'No. 1 will display signals London to Dover for engine 85.' Rule 218 reads 'When a train is named in a train order, all its sections are included unless particular sections are specified, and each section must have copies addressed and delivered to it.' Under the example cited, according to the reading of Rule 218 all sections of No. 1 will display signals for engine 85.

"As it is intended to bring the Standard Code to a state of perfection would it not be a good idea to change the form to read '1st No. 1 will display signals London to Dover for engine 85? This will conform to Rule 218 and remove the seeming inconsistency."—C. H. G.

Answer. Rule 206 of the Standard Code provides for the manner in which trains shall be designated in train orders, each section being specified when there is more than one. Rule 218 was formed to make provision for cases where sections are not specified, yet, for some reason, more than one section is run. This sometimes happens when additional sections

of a certain train are run after orders are issued to other trains. This rule therefore, being formed to cover unexpected developments, would hardly be called into use in the case of issuing signal orders, for when such orders are issued there is no uncertainty as to the number of sections to be immediately provided for.

When the second example of Form F is used, "No. 1 will display signals London to Dover for engine 85," the latter train understands that it is to be the second section. There could be no other understanding. If there were three sections preceding engine 85 this form of order would not apply. It only applies where a train which is originally the only section is directed to display signals for a following section.

We doubt if the modifications suggested by our correspondent would be either plainer or more consistent than the pres

ent form.

88. Form F-Continued.-"Could not the first example under Form F be changed to read Engine 20 will run as 1st No. 1 London to Paris?' Rule 20 provides for the carrying of signals, and the words 'display signals and' seem entirely unnecessary."-C. H. G.

Answer. Yes, we know of no reason why the suggested form would not be sufficient.

Locomotive Front Ends.

MR. WM. MCINTOSH: The locomotive

front end is only useful when attached to a boiler that is properly designed and has sufficient capacity to meet the requirements of the service for which it is intended. Next in order, the exhaust pipe must be of suitable form and of proper dimensions, both in diameter and in length. Experiments have been made with adjustable nozzles for exhaust pipes, but there does not seem to have been developed any that have come near enough meeting the requirements to be adopted for general service.

de

It is generally conceded that draught governing appliances should be signed, as far as practicable, on the lines employed in ejector tubes and air and water conduits, namely, the lines of least resistance. With front end arranged in this way there ought

not to be much demand for spark collectors, as the carbon that now so fre

quently passes through the tubes and

forms sparks would be consumed in the furnace through the action of the softer though more intense draught that would be developed by obtaining action through all of the tubes instead of through only a portion of them, as often occurs where imperfect action is obtained. Some effort has been made to adapt the ejector tube principle to smokestacks, principally by widening out the base and the bell mouth form. This principle has been carried to the top of the deflector plate, but only partial benefit was obtained, for the reason that this plate terminates with shear edge at the bottom and from under which we would expect the gases to turn abruptly to the smokestack with more or less of a reactionary effect on the moving

current.

What could serve better would be a deflector plate constructed on the letter "S" or "OG" lines, which form, while being somewhat difficult to shape on account of the necessity of its crossing the exhaust pipe, would, no doubt, when completed, furnish a smoother and more continuous current that could be directed in its action to embrace in a more general way all of the tubes in the boiler.

It does not seem to make much difference about the location of the netting in the locomotive front end, the principal requirements seeming to be sufficient area of opening to furnish to the gases a free exit, and that a fine adjustment of draught ap

projecting down into the smoke-arch a certain distance, I never succeeded in finding that there was any advantage in it; in fact, so far as my experience goes, the bell-mouth stack attached to the smokearch is likely to serve the best purpose. I have recently heard of a double stack, but only in a general way. I can not recall now where it is in use, but I have it in mind as being an inside stack projecting down in the usual manner but considerably smaller than the outside stack, leaving an annular opening around it, and it occurs to me that there might be some merit in a design of that kind. It was quite new, anyway.

pliances is desirable and necessary. It is a fact well known by those who have had to give the arrangement personal attention in a practical way that often the most insignificant change in the location of some of the parts will produce results of marked importance.

The form of the locomotive front end with its restricted area and nest of pipes makes it difficult to introduce ideal conditions, but the best results must be looked for where the ejector principle of easy lines and smooth turns has been followed.

I would suggest that Mr. Vaughan would have some difficulty in standardizing the front ends by reason of the great variation there is in the shape and size of steam pipes and that each distinct class of locomotive would have to have a front end suitably arranged for each particular class. With reference to the inside stack

MR. A. M. WAITT: I have always taken a great deal of interest in this particular subject. the front end arrangement of locomotives, and it has been very interesting during the past fifteen years or so to notice the change of public opinion with regard to what the proper design of a front end should be. I remember that when I was first employed in connection with locomotive department work, I was assigned to some studies in that direction, taking in the front end arrangement and also the arrangement as to brick arches in the fire box, with a view to bettering the draft and the steaming and to reducing smoke. At that time, as we all remember, the front ends were supposed to be spark collectors, and they were extended out as long as was thought necessary with the intention of catching the accumulation of the sparks in a trip over