MR. PAXTON (Superintendent Motive Power Colorado and Southern): High steam pressure, as used nowadays, is accountable largely for the difficulty we have in lubricating locomotive cylinders, and if we keep on increasing the pressures we will find added difficulty in finding a fluid that will do the work. We will be compelled to resort to graphite, or do like the government the gentleman speaks of, run without oil at all.

There is no other single thing that has a more serious bearing on the matter of proper lubrication than water supply. I remember not long ago having been on a road in the South where we had as good water as I ever saw, generally speaking, but there was a large per cent. of soda in that water, which was principally artesian. This set up a tendency to "priming" which we found very difficult to contend with. Such a large percentage of moisture followed the steam out through the throttle valve to the cylinders that it made it almost impossible to get satisfactory lubrication. I have seen more than one-third of the power of the engine consumed by internal friction set up in this

way.

The common car oil box is distinguished for its simplicity and accessibility, and the difficulties that beset us in the driving box are of a character that are hard to overcome, and modern construction seems to be complicating these matters instead of improving them.

I noticed, as referred to by a writer recently, in a late number of the Engineering Magazine, an article in regard to the use of "dope" in driving box cellars. The idea was given out by a master mechanic on the Delaware-Lackawanna. He claims to have applied it to about fourteen engines, and with very satisfactory results. He states that on consolidation engines, during a period of six months, in which a test was made, that the cost of driving box lubrication per thousand locomotive miles run was only 10 cents, while the cost for lubricating with oil for the same work had been 84 cents. He mentions the fact that they have not had a single instance of a hot driving box while they have used this grease.

The pressure carried on the modern locomotive is much higher on the average than that obtaining a few years ago. Four years ago I was handling a class of 18x24 inch, ten-wheel engines, carrying 180 pounds of steam, and operating in freight service. During the last six months in 1898 our cost per thousand locomotive miles for lubricating those engines was an

average of $1.34. Our figures today are 94 per cent. higher than that, and I believe that the increased cost is due more than anything else to that difference of 30 pounds of steam, between 180 and 210, supplemented, perhaps, by an inferior water supply.

MR. C. B. TOPPAN (Pennsylvania Oil and Gas Company): The question of lubrication in any form is greatly governed by this degree of quality. We generally speak of an oil as burning, as a fuel; in truth, mineral oils do not burn, in the form of oil; it is not until the requisite amount of heat has been absorbed by the oil, which is required to expand it into a gaseous body, that ignition takes place.

If any of you are familiar with the process of refining oil, you know that it is a matter of distillation, bringing the product which you are handling down to a point of a gas, and afterwards changing it to the form of oil which you wish to use. That a better knowledge of the subject may be obtained, nothing would impart the same more effectually than a visit to an oil refinery, and there watch the course of the fluid in its passing from the crude to the refined state. As I have stated, the process of oil refining is distillation, and under certain conditions desired, concentration. Distillation is the rendering of the fluid product into a gaseous body within the still, "the value and extent of same passed over being governed by the temperature maintained in the body of oil in still," the passing over and through the warm to cooling coil, thence to reception tank where oil in a fluid state appears, the equivalent of the gases produced at a given temperature. After the passing of the more volatile portions, superheated steam is properly introduced into the still. This, with its high temperature, mingles with and passes over some of the remaining lighter portions of the lubricating oils, concentration taking place; subsequent chemical treatment for the purpose of purifying more perfectly this product, produces what is known as cylinder stock, of very high flash or gasing point test. The point of flash ignition, to reach the fire test or point of continual burning, enough more heat must be absorbed, so that a continuous flow of gas will obtain-enough to produce continued burning. Bear in mind, mineral oils never burn except they have reached this form. Heat is the primary cause of this condition, and here is where it applies to our modern engines under high steam pressure-210° F.

We now come to the action of this oil in service, commencing with the lubricator. And right here I have to disagree, not only with the gentleman who spoke on this subject a few moments ago, but with other statements, printed and oral, which have been made heretofore.

They speak of the oil as requiring so many minutes to pass from lubricator to steam-chest, after lubricator has been started, appearing there in same form as when it passed up through sight glass. Now, all seem to have lost sight of the fact that steam under boiler pressure and temperature enters greatly into this work. Upon opening the steam throttle to lubricator, steam enters and passes through regular passages within lubricator to the oil pipes at point where the same join lubricator; here it meets with and takes up the oil which has come up by way of the feed tubes via choke plugs, and slightly expanding and greatly condensing, rushes on to the steam chest, not in minutes of duration of time, but in the small fraction of a second, and delivers the oil taken up in its passage to the steam-chest in the form of an emulsified solution and steam. It is here met by the steam on its way from the boiler to the cylinders, which steam becomes saturated with oil, and passes on to its work. How much or how little this work is assisted by the oil depends entirely upon the amount received.

If, in the general practice of 15 or 18 years ago we have determined that a certain amount of oil per minute, measured by the drop, as it appears at the lubri cator, was necessary at that time, and for the power of that date, and we attempt to apply the same rule to our modern large engines, with double the extent of friction surface, it is but plain that we must fail in our efforts to obtain perfect results, economically maintained.

Throughout this progress of the oil from the lubricator to the exhaust, you will notice close analogy to the process observed in the refinery, in the production of oil stock.

Passing, now, to the driving box and journal, admitting, as we must, the pinching of the brass at or near center line of journal, I will cite a point of small ex

tent: At some point along the side of the brass, where the edge of same has worn to a close fit with the journal, the oil, as it comes upon the face of the journal from contact with the waste in cellar, meets with this sharp edge, where all the oil is scraped off; the result is a line extending around inside of brass which is void of oil: here friction is great, heat is generated, the adjoining portions of the brass and journal absorb this heat, until it begins to be perceptible to sight and sense of feeling. This heat is communicated to the film of oil on other parts of bearing, raising its temperature until it proaches the point near which it was set over or concentrated in the refinery, and when it reaches this point, lubrication ceases and internal friction begins. Thus you see that both in cylinders and journal lubrication, approximately the same conditions take place, under heat, as were used in the refinery in the production of the oil.

ap

There is another little point in connection with oils which tends to produce internal friction.

All oils are composed of minute globules; in some, these globules are round in form, others are oblong. Under microscopic investigation, it is found that when two oils of such form of globules are mixed, perfect action of the oils can not take place, and the result is friction of the globules within themselves. Small though this may be, it is sufficient to cause a deteriorating effect.

It is impossible at this time to enumerate all the various features which combine to make a perfect lubrication of surfaces. But, considering the rapidly increasing dimensions and corresponding difficulties met with daily in modern locomotive practice and car service as well, I would suggest that the management of railways, master mechanics and superintendents should examine more closely into the nature and conditions of the oils they are using, visit the refineries, and become closer acquainted with the methods of refining. You will find it an instructive and entertaining expenditure of time and a source of useful knowledge.-Rocky Mountain Railway Club, November 22, 1902.

The Essentials of a Good Draft Gear.

E. M. HERR (Manager Westinghouse Air Brake Company): The term "draft gear" is frequently used to mean either

the whole or some important part of that portion of a car through which the stresses, occasioned by either pulling or pushing the car by its draw-bar, must pass to the car framing. It seems, there fore, important to first define the term "draft gear."

My definition would be the broad one covered by the statement already made, viz. The draft gear is that part of the car transmitting to the framework of the car body the pulling and pushing stresses imposed upon the draw-bar. This draft gear is composed of three essential parts.

1. The draw-bar with its yoke and followers or other means of transmitting pulling and pushing stresses to the second or yielding portion of the draft gear.

2. The yielding portion, usually a spring or substitute therefor, interposed between the draw-bar and attachments and the third or fixed portion of the draft gear.

3. The fixed portion or draft gear attachments to the framing of the car.

Having now the draft gear composed of the draw-bar, the yielding portion, and the attachments to the car, what should be said to be the essentials of a good draft gear?

This more than any other part of the car structure is subjected to severe shocks and stresses both of tension and compression. It is, therefore, manifest that great strength is of prime importance. A designer with the object of the greatest possible strength in the draft gear would make the draw-bar of the strongest possible material, see that its attachments were also of the proper cross section to withstand fully as great stresses as the bar, and that they were secured to the car framing firmly with bolts, keys and other accessories, arranged to distribute the stresses transmitted to the car sills as advantageously as possible. Such a design would leave out entirely the second or yielding portion of the draft gear because it is much easier to attach a draw-bar to the car framing directly than by interposing a spring or other yielding member between the draw-bar and the car. Not only this, but were pulling and pushing stresses only to be considered, the interposition of this spring would surely make a weaker and less secure attachment. Is this yielding portion then a nonessential to a good draft gear which can be omitted, or have we failed to consider some condition affecting its design?

Slight consideration will disclose the omission. The pulling and pushing strains imposed on the draw-bar are not gradually applied, but generally come as shocks or blows. It is well known that the destructive effect of a blow is greatly increased when it is delivered against a rigid body and correspondingly decreased when the thing struck is yielding. It is, therefore, clear that another essential of a good draft gear is interposed yielding resistance.

It was formerly supposed that if this yielding portion of the draft gear was equal to or slightly in excess of the tractive effort of the locomotive hauling the cars, ample provision had been made. Were the strains imposed upon draft gear never greater than the tractive power of the locomotive drawing the train, a yielding portion of the draft gear equal or slightly in excess thereof would be sufficient. Unfortunately for the simplicity of our design, this is not the case. Owing to the enormous weight of modern cars and locomotives, these bodies when once set in motion have in themselves, by reason of such motion, an amount of energy or capacity to exert strains and stresses in their draft gear compared with which the tractive power of the most powerful locomotive is small. Witness the ease with which trains are often broken in two, three or more parts in passing through sags or over "hog backs."

The forces which cause this damage are not gradually applied on the draft gear. They usually come as blows caused by bodies of great weight moving with moderate velocities. In fact, the weights of modern cars and locomotives are so great that unless the speed with which they come together is moderate, no draft appliance even with the greatest possible amount of yielding resistance interposed, can withstand the shock. In fact, as instanced above, their strength is sometimes exceeded usually because of yielding resistance of inadequate capacity.

It is of great importance to keep carefully in mind the difference in effect produced by the impact of bodies moving with different velocities. We are as likely to reach erroneous conclusions in designing draft gears if we reason from the effect of impact from bodies of too high as of too low velocity. Not only, therefore, is the yielding portion an essential part, but it is so essential that no draft gear without it could long endure. It is also evident that the amount of yielding

resistance formerly adequate becomes en tirely inadequate with the heavier cars and locomotives and the stronger and more rigid car bodies now used.

Can this greater yielding resistance be obtained satisfactorily by simply increasing the number or strength of the springs formerly used with good results? Within certain limits only can this be done, for it must be remembered that when a spring is compressed it contains an amount of stored energy capable of doing work or increasing stresses in the parts confining it just as surely as the moving body of the car or locomotive itself. The strains these springs are able to and do exert are practically equal to the force which compressed them. Inasmuch as cars must be run in trains, where the draft springs act one upon another, the cumulative effect of the recoil of a number of such powerful springs cumulating at some point in the train, would result in stresses so high that the other parts of the draft gear could not withstand them even if such stresses were not increased, as they often are, by the power of the locomotive drawing the train. This action often results in the breakage of couplings when long trains, especially of empty cars, are stopped at hig speed by an emergency application of the air brake.

It is, therefore, essential not only that the yielding portion of the draft gear be of large capacity, but that it should have little reaction or recoil.

Now, having the strongest possible draw-bar properly arranged with an adequate amount of yielding resistance with minimum recoil, the third or fixed portion of the draft gear should be made of the strongest available materials and secured to the sills of the car in such a way as to bring the heavy strains of pulling and the still heavier buffing stresses upon the parts of the car best adapted to receive them.

No specific rules can be laid down, as the design of cars is so different that the disposition of these attachments so the various stresses come on those parts of the car which can best resist them, is the great essential. It is also essential that the draft gear attachments, or the socalled fixed portion should be so designed as to admit of proper inspection and facility in making repairs or renewals.

The essentials of a good draft gear, therefore, are:

1. A draw-bar of the strongest material to resist blows, jerks, etc., with se

cure attachments to transmit stresses received.

2. Adequate yielding resistance with minimum recoil, securely housed.

car,

3. Fixed attachments to the strong and well designed for ease of inspection of the gear, and well secured to the car so as to distribute and dispose of all stresses as advantageously as possible.

ROY V. WRIGHT (M. E., P. & L. E. R. R.): The fact seems to be generally recognized among railway mechanical men that the ordinary spring draft gear is too light for the heavy service now required of it. The high capacity cars and the large locomotives now generally used, and in the case of the steel cars, the stiff construction have shown it to be defective in many respects. A careful study of the conditions and requirements to be filled lead us to believe that the following are some of the essentials of a good draft gear:

1. A capacity of at least 100,000 pounds. That is, it must have a yielding resistance amounting to this much, and it must be able to stand a blow of several times this amount without injuring it. 2. A total draw-bar movement of at least 2 inches.

3. A good draw-bar movement under ordinary pulls.

4. A small amount of recoil compared to its capacity.

5. It must be substantial. Repairs, except for unfair usage, should not be necessary. Parts should be of a simple and substantial design, and as few in number as possible.

I. The Standard M. C. B. draft spring has a capacity of 19,000 pounds. The twin spring and tandem spring arrangements would therefore have a capacity of 38,000 pounds. The tractive power of the large freight locomotives now generally used is greater than this.

The following is a quotation taken from the report before the Western Railway Club on tests made with the Westinghouse Dynamometer car by the Lake Shore and Michigan Southern Railway Company:

"From the general results of the tests it is believed that the tensile strains in draft gears with careful handling will frequently reach 50,000 pounds, with ordinary handling 80,000 pounds, and with decidedly rough handling, fully 100,000 pounds, while the buffing strains can be placed at 100,000, 150,000 and from 200,000 to 300,000 pounds, respectively. In extreme cases, the buffing strains will go