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SOME TECHNICAL POINTS EXPLAINED

NOW that I am a retired engineer, I wish to give others the benefit of my long and varied experience in handling a locomotive. Every engineer knows how essential it is to be able to locate the trouble when anything goes wrong with his engine, but it takes years of experimenting to be able to do this accurately, so I will here add some helpful information in the form of questions and answers. I have asked hundreds of engineers for the solution of these problems, and put the same questions to master mechanics without once receiving a correct answer.

QUESTION 1: Why is it that the guides of a locomotive run dry and chafe quicker backing up than when going ahead?

ANSWER: When an engine is running in forward motion, there is an angle formed at the front end of the main rod with the cross-head. Working steam in this motion causes the cross-head to press the top guide, so long as the engine is running forward. The weight of the main rod, cross-head, and piston rod counteracts the power generated, by working steam to the amount of the weight in said rod, cross-head, and piston rod, which gravity controls. In back motion, it is the contrary, the weight being put on the bottom guide and power of the engine also. I have never figured out how much more friction there is on the bottom guide in backing up than on the top guide in running ahead, but it can be readily seen that you have all .the weight of the main rod, cross-head, and piston rod in addition to the power of the engine, when running backward. I reasoned this out while I had charge of my first regular engine in 1861, when running a construction train on the Memphis and Charleston railroad.

QUESTION 2: How do you locate the blow on an engine?

ANSWER: Watch the top of the stack when the fireman throws coal into the fire-box, after the door is shut. If the engine is not blowing, the smoke will come out of the stack in a twist on both sides. If blowing on either side, the smoke will not twist on that side, so if she is blowing on both sides, the smoke will not leave the stack in a twist on either side. I learned this fact from observation while still a young man, and have never placed an engine as others do, to locate the blow, in forty-five years.

QUESTION 3: Why do engines gum up their cylinder packing piston rods, and valve stems?

ANSWER: Because the valve-rod, which is the most important part of the valve motion of a locomotive, is not the proper length. There was an engine overhauled in the Selma shops over thirty years ago, that was so gummed up in valve stems and piston rods that she could not be run more that one trip without packing the piston stuffing boxes. In those days, we used fibrous packing for the purpose. I told the Master Mechanic that if he would let me run that engine a trip, I would stop her from gumming up. He made no reply, but looked at me in a doubtful manner and walked off. For three months he and the Engineer worked on her trying to overcome this defect, but without success. At last, he said to me, "John, I am going to let you run the a I a trip, as you say you can stop her from gumming up, for I have done everything in my power and failed." I replied, "You don't know where the trouble is. I will fix her before I return to Selma." I did so. This one thing has been a standing puzzle not only to the men and foremen of the Selma shops, but all over the United States, Canada, and Mexico. The way to get the proper length of a valve-rod is to cover the ports exactly, then plumb the rocker arm, and that will give the exact length of the valve rod. The foremen and master mechanics with whom I have come in contact think this is not very important, but experience has taught me, that if the valve-rod is not the proper length, you cannot set the valves to be perfectly square. I have known foremen to have the valve-rod shortened or lengthened to divide the travel of the valve, which is an error, because it changes the speed in the travel of the valve in crossing the centre, which I will illustrate. If the valve-rod is not the proper length it will not travel at the same speed from one point to another in its extreme limit. We all know that when engines are drifting, a vacuum is formed at each end of the cylinder. By having this valve-rod accurate, the propelling power overcomes the vacuum to such an extent that it prevents the sediment in the front end from reaching the cylinders and steam chest, through the exhaust pipes.

QUESTION 4: Why is it that locomotives wear their tires flat at certain points?

ANSWER: Because of the construction of the locomotive. The greatest wear on a tire is when the engine is leaving its forward centre, because the crank is between the wheel centre and the fulcrum, which is the rail. The power turning the wheel has a tendency to skid it, and does skid it on the rail every revolution while working steam. The flat spot on the tire, caused by leaving the back centre, is not as long as the one leaving the forward centre, because the leverage is not between the wheel centre and the fulcrum, which is the rail; so all the skid on that centre is to take up the lost motion in boxes and side rods. Thus, in order to overcome this defect keep boxes in good shape, wedges set up properly, and the lost motion taken up in side rods. Men in various railroad departments, even superintendents of motive power on the various systems all over the country have failed to explain this point scientifically. Some have advanced one idea and some another. I asked a master mechanic once if this question was ever taken up by their Association, while in conventions. He replied that it was. I then requested him to explain it to me. He said, that as the engines wore their tires faster on level roads, they had attributed it to sand. I gave him my reason as stated above, illustrating it with a bicycle, whereupon he acknowledged the solution to be entirely satisfactory. That man is now Superintendent of Motive Power for the Mobile & Ohio System. I don't know whether he gave the secret away or not, but I do know that I am the originator of it.

QUESTION 5: How is it necessary to proceed when anything happens to the valve motion, so that the engine has to be put on one side?

ANSWER: They are liable to stop on the centre, and the present mode of getting them off by pinching, or jacking, is an uphill business; in fact, almost an impossibility with the up-to-date locomotive and the number of men now on the trains. When an engine is disabled as stated, the main rod must not be disconnected, for should she stop on a dead point on the live side, the valve can then be changed on the dead side, so as to move her off the dead point on the live side. Then cover the ports on the dead side and she is ready to do business on the live side. The superintendent of motive power or master mechanic may say that the cylinder packing or piston head will run dry and chafe, but if you will feed your lubricator more on the lame side than you would ordinarily, it will not chafe either cylinder or cylinder packing, because there is always a small leakage between valve and seat, which will allow steam and oil to pass into the cylinder. If there should be any oil left in the steam chest, when the engine is drifting, the vacuum formed by the piston head will take it all in, as well as any that may feed in from the lubricator while the engine is drifting. The piston rod should be lubricated at the gland, by means of a cup, or swab, to prevent the piston rod from becoming heated from the piston rod packing.

QUESTION 6: Why is it that locomotives do not drift as we think they should?

ANSWER: Several defects may be mentioned that will retard the drifting. Sometimes engines are not properly quartered; sometimes they are out of tram; side rods not the proper length; or want of lubrication in machinery and cylinders. But the main cause is due to the use of valve cylinder cocks. When an engine is drifting, a vacuum is formed by the piston head, and atmospheric pressure fills the cylinder with air at every revolution. This air cannot pass out through the cylinder cock, so the piston head has to force it from the cylinders through the openings, or ports, in valve and valve seat; therefore, it retards the drifting of a locomotive more than all other impediments mentioned, and plug cylinder cocks should be used instead of valve cocks. There would be very little, if any, air drawn into the cylinder, if plug cocks were used, because the propelling power would overcome the vacuum, and allow engines to drift as they should. Relief valves and valve cylinder cocks are impediments to a locomotive, for another reason. While locomotives are drifting, cold air rushes in at these openings and chills the cylinder and steam chest away below the temperature of steam, thereby causing condensation in cylinder and steam chest, until heated to the same temperature as steam. If any one doubts this statement in regard to valve cocks and relief valves, just let him get the superintendent of motive power to fit up a locomotive with plug cylinder cocks, and it will verify my words. I was talking with a superintendent of motive power a year ago about the different builds of locomotives and their deficiencies. We finally took up the Mallet Compound Locomotive, which, he said, scarcely drifted at all. I asked him if he knew the reason for this. He replied that it was on account of its length, numerous bearings, and friction. I told him that there was a scientific reason why they did not drift as well as any other locomotives, in comparison with the size, and would like him to point it out to me. He said he was not able to do that. I told him if he would give the problem a little thought, he could solve it, but he decided that he had so many things to occupy his time and attention that he could not put his mind upon that subject just then. I asked him if he had road foremen of engines on his system. He replied in the affirmative, adding that they were as good as any on any system. I then requested him to put this matter before them, and asked that they report to him as early as possible. I have frequently met this gentleman since, but he has never mentioned the subject, therefore, it is very evident that his foremen have not given him the desired information. Now, Brothers, just take a common-sense view of this matter! There are two cylinders twenty-two inches in diameter, and two that are thirty-two inches in diameter, which will fill with air under the present construction of cylinder cocks and relief valves. Now, it is clear to any thinking man that this air, having to be forced out by the piston head, will undoubtedly retard the speed of the engine at every revolution, and, hence, is the chief cause why the Mallet Compound Locomotive does not drift as it should. This defect can be remedied as above stated.

QUESTION 7: What is the duty of the engine, or pony truck?

ANSWER: Most any one would say "to carry the weight of the front of the engine." It has an additional use. It entirely controls the tracking of a locomotive while running forward or backward, which is a very important part of the work. This truck is generally left to be fitted up and looked after by what is considered a third-class workman, which should not be the case. Only a first-class mechanic should build and adjust it, for when it is in perfect order with wheels, etc., an exact match, and the male casting attached to cylinder saddles precisely in the centre of the two cylinders, the engine will track to perfection in both motions. About twenty years ago, this road received five passenger locomotives, four of which performed all right, but the remaining one rode so rough that the Engineer in charge made complaint to the Master Mechanic. He also spoke of it to his Brother Engineers, and talked it to everybody he came across. The master mechanic, Mr. Petrican, and a number of engineers rode on No. 163 a number of times in the course of five months, but couldn't locate the trouble. It so happened at one time that this engine ran as first section, and mine as second section of the same schedule, one hundred and twenty miles from Selma. We had a meeting point with another train, and having to wait twenty minutes, I ran up behind section number one, and getting off my engine, went forward to have a conversation with the Engineer. He was lying on the platform, and when I asked him what was the matter, he answered, "That engine is killing me!" "What is the trouble?" I said. He replied that he didn't know. This was three-thirty A.M. He asked me if I would run the 163 to Anniston, a distance of twelve miles. I did so, and before going half the distance, found the trouble to be in the engine truck. Upon coming up with me at Anniston he wanted to know what I thought of her. My reply was, "She is a holy terror!" When I told him that the rough riding was due to the engine truck, he did not credit it, and said he wouldn't report that to the Master Mechanic, for the truck was all right. I then said, "Well, tell him that I say there is a deficiency in the truck." He agreed to that, and when Mr. Petrican made the examination, he discovered that the wheels varied as much as a quarter of an inch in diameter. This defect was remedied, and the engine went out on the road in a much better condition, though at times she would have what we engineers called "fits," when she would run fast on straight lines. Later on, that engine was turned over to me, and when I would get her to a high rate of speed, she had "fits" with me. I asked the Foreman to examine her and find out if the male casting on the cylinder saddle, which set in the female casting, was in the center of the cylinders. He discovered it was nearly three sixteenths out. He adjusted this properly, and the engine was all right, and as good a riding engine as one could put foot on.

About five years ago, the General Superintendent of the Western District of the Southern .Railway told me in Rome, Georgia, that they had a passenger engine that cut up in such a manner, when run at a high rate of speed on a straight line, that a man would believe she was off the track, and that upon the occasion of one of her spells a fireman had jumped off. "The fact," said he, "was reported to me, so I took a ride on the crazy locomotive myself, and she rode so rough that I actually couldn't sit on the seat box. I asked the engineer in charge how long she had been in that condition. He replied that it had been that way ever since he had started to run her, and added that the engine had been worked on for some time, but the trouble had not been located. Now, I want you to tell me where the deficiency is." I answered that if he would keep it to himself, I would do so. I then explained to him what I have already said in regard to engine 163, and asked him to go to the shops and investigate the matter for himself. In a short time the engine was put back into service, and there has been no complaint about her, on that point, since. This defect can be partially overcome by giving an inch, or more, lateral motion between the hubs and boxes of the truck, when the trouble is only in the male casting.

QUESTION 8: How can you tell when the male casting of the engine truck is not in the centre of the weight in front of the locomotive, and how can it be overcome?

ANSWER: When it is not in the centre, the locomotive will always run to the light side, therefore, to overcome this, simply put more weight on that side, which will make truck and driving wheels run straight on the track, if the weight is equally divided on the engine truck. I have known master mechanics and foremen to throw the driving wheel back on one side as much as an eighth of an inch to avoid cutting the flanges on the opposite side, and I have never yet seen that it made any difference in the tracking of the engine. It only makes the boxes run hot, and the engine ride rough. Think of a wagon or any kind of a vehicle. We all know that the front wheels control the tracking of the back wheels; in the same manner the front truck controls the tracking of the driving wheels of a locomotive, in both forward and back motion. Therefore, builders should be very careful in constructing an engine truck, as it adds safety to a locomotive, and gives satisfaction and comfort to the engineer.

QUESTION 9: Why is it that a lubricator will not feed as regularly when working steam, as when the engine is drifting?

ANSWER: The trouble is that the openings in choke plugs are too large, and they always grow larger as long as the lubricator is used. To overcome this deficiency, open the shut-off plug just above sight feeder, not more than one-half turn, or less, if sufficient. You will find that it will feed just the same while working steam, as when the engine is drifting. The reason why lubricators will do this is because you have boiler pressure in the pipe that conveys the oil to the steam chest. Engineers are often mistaken in making their reports. When valve-strip springs break and the engineer doesn't know how to locate it, sometime the machinist has to take off both steam chest covers before the broken spring is located. If an engineer will have his fireman stand on the steam chest cover when he applies steam to the engine, he will feel the strip when it strikes the friction plate, as the strip always drops down when the spring is broken, and the steam shut off. Or, you may put your ear against the steam chest, and when the engine is given steam, you will hear the valve strip strike the friction plate. So you need never make a mistake in reporting broken valve-strip springs.

QUESTION 10: Why is it, when removing a pair of wheels on account of skid flats, that one wheel sometimes has a flat place two and one half or three inches, while the other wheel on the same axle has a flat place only one half an inch, or less?

ANSWER: I have asked a great many men in charge of car works, and they have invariably replied that one wheel has more chill than the other. But this is not the case. It is because the rail on the side where the wheel is flattened so badly is sanded, and the other is not. Then both sand pipes should be kept open, so that whenever sand is applied, both rails will get the benefit.


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