The general principles upon which pneumatic blow-off cocks are constructed are as follows: An inner or check valve is so arranged as to be kept seated by boiler pressure and prevents water from escaping to the atmosphere. Against this valve rests the stem of an air piston, which is confined in a small cylinder over the check valve. To the cylinder containing the air piston a pipe is attached and connects with some pipe on the engine leading to the main reservoir pressure. In this connecting pipe is placed a cutout cock. When air is turned into the air cylinder of the blow-off cock from the main reservoir the piston is forced down, unseating the check valve against boiler pressure, allowing the water to escape. 62. Grease Cups.-"Explain the principle of the grease cup, and what is the objection to using water on a hot pin when grease is used?"-W. F. B. Answer. The principle upon which the grease cup depends for its operation is that of hydraulics; it is pressure and compression, coupled with expansion. The cup is filled with grease; then the cover is applied and the plug screwed down, subjecting the grease to considerable pressure, forcing same through the small hole in lower part of the cup and to the pin. When the plug is screwed down the grease in the cup is slightly compressed, and the expansion which takes place in the grease as pressure is gradually reduced by the consumption of the lubricant on the pin is sufficient to maintain a slight flow of grease for some considerable time. As a general principle, water should not be used on hot pins at all. When it is used it should be only as a last resort, and under these conditions could be used the same in connection with grease cups as with ordinary oil. Train Rules and Train Practice. Answers by H. A. Dalby. 81. "Right" Orders.-"Odd numbers run west, even numbers east. East-bound have right of track by time card, "Order No. 5: No. 1 has right over No. 4 G to F.' Arriving at M No. 1 receives order No. 7: 'No. 1 will meet No. 4 at C.' Arriving at C No. 1 receives order No. 10: 'Order No. 7 is annulled.' Can No. 1 proceed to F with right of track as given her by order No. 5? What about No. 4?"-C. A. T., Forsyth, Mont. Answer.-The American Railway Association has ruled that a train, having been given right over another between certain points, holds that right until it is fulfilled, superseded or annulled. If a meeting point is afterward made at a station between the points named in the order, the train to which the "right" was given remains the superior train. It naturally follows that if the "meet" order is annulled the "right" order remains in effect. 82. Second Section Annulled.-"An extra gets orders to run from A. to D. D is an intermediate turn-around point. The extra held orders that first No. 1 will run two hours late and second No. 1 will run four hours late. First No. 1 arrives at D not carrying signals. Extra gets orders to run from D to A and has time to make C for second No. 1. Second No. 1 falls down on another division east and does not run. How would the extra be governed? Some men claim they would not require the annullment of second No. that the order concerning second No. 1 1, as first No. 1 did not carry signals and did not concern the extra on the return trip. Others say they would require it." -R. H. C., Rat Portage, Ont. Answer. The orders held by the extra do not agree with the signal indications, or the absence of them, on first No. 1. Therefore some explanation was due the train which held the time on second No. 1. If we were running the extra we should inquire of the dispatcher concerning the fact that No. 1 displayed no signals and if informed that there was but one section we should not ask for the annullment of the second section. All we should desire would be to know that there was no mistake in the absence of signals on first No. 1. 83. Clearance Cards.-"Is it customary to issue a terminal clearance at intermediate turn-around points? They are not used here at those points."-R. H. C., Rat Portage, Ont. Answer. We think it is customary to designate on the time-table such places as trains are required to obtain orders or a clearance, and such designated points are usually initial points for all trains or for certain trains, or important junction points. The line from which this question comes, the Canadian Pacific, has a form called the "Terminal Clearance," and it is this to which the question refers. From its name we should suppose that it is necessary for a regular train to receive this form of clearance before leaving its initial point. Whether an extra leaving a district terminal or leaving an intermediate (or "turn-around") station should receive one in addition to its orders would be determined by the division officers, but our opinion would be that in the case mentioned by our correspondent it would not be issued. Railway Club Proceedings Locomotive Lubrication. MR. ROESCH (T. E., C. & S. Ry.): In speaking of the frequency of hot driving boxes as compared to regular engine truck boxes, let us look at the various causes which may contribute toward this result. Through the courtesy of our Mechanical Engineer, Mr. Kessler, I obtained the sketches here shown (Figures 1 and 2) drawn by Mr. E. Saylor. A word in regard to side oil holes. Notice them. They are in the very best location to carry grit to the journal, and when this brass becomes slightly loose, the oil, instead of flowing down to the journal, will simply follow the box and flow between it and the brass, and never touch the journal at all. D 88 Fig. 1. Locomotive Lubrication. Figure 1 shows a section through an ordinary driving box with underhung springs. You will notice how the weight is carried on the sides of the box-helping that pinching action spoken of previously. This form of spring suspension also allows the weight to be entirely supported on but two corners, producing a twisting strain, and, of course, a hot box. This type of box is notorious for running hot. The type that has a crooked hook-shaped hanger is not much better. Another point I wish to call to your at tention is, this brass, as you know, is put in under pressure; this compresses the brass on the inside. As it wears, the strain is relieved, allowing the brass to close on the journal; at the same time, a sharp edge is being worn on the brass. This edge, and it need be but one-eighth inch wide, acts as a nice little cutting tool or scraper to scrape the oil off the journal-a dry spot only one-eighth inch wide is enough to produce a hot box. Fig. 2. Locomotive Lubrication. Now take a look at the engine truck box, as shown here (Figure 2). Notice the babbit bearing, small bearing area, flat surface on top of brass, with spring saddle pressing straight down on it. No pinching action here; no care here; no particular attention, and very few hot boxes. I believe that here is a chance to learn something. Let us determine which it is the bearing metal or the fitting, and, once decided, let us adopt it. Most of us have seen engine truck brasses, old style, applied, having two babbitt strips projecting about one-eighth inch. These took all the weight. Think of it!-the weight resting on two little three-quarter-inch strips, or over 1,000 pounds per square inch, and yet this bearing ran cold. Looks mysterious, does it not? Yet there is nothing mysterious about it. We are too prone to look at some things as due to some mysterious agency, and at others as inevitable. Let us quit this line of non-reasoning, and dig for facts. When we find anything right, find out why; and, when wrong, correct it. To give you a better idea of the growth of the modern locomotive, we show here (Figure 3) a comparison of the cylinder and journal areas of a 22x28 and 17x24 engine. The outer lines show the area of a Fig. 3. Relative Cylinder and Journal Friction Areas. The larger figure in the left-hand corner shows the journal area of a modern engine. The smaller one within it is that of the 17x24 engine. Note this increase over 69 per cent. MR. G. W. RHODES (Assistant General Superintendent B. & M.): The principal thing that we have done to excite interest is that we allow our men one pound of new waste without any charge if they return two pounds of old waste of a quality good enough for packing purposes, and it is quite surprising what an effect that has in the use of waste. I was interested in the matter because, when this started, some years ago, the other end of our line at Chicago- the C., B. & Q. portion of the Burlington-heard of it and did not think much of the idea. The General Auditor recently sent me a copy of a letter that he wrote to the Superintendent of Motive Power, mentioning the above facts, but adding that he now finds that the performance of the B. & M. railroad in the matter of miles to the pound of waste is so far outstripping the other portions of the system that they ought to start something of the same kind. I do not believe we realize fully the extent oil is used wastefully about the railway. If I were a master mechanic, and really wanted to improve my oil record, I would not bother much about the engineers and firemen. The shops and roundhouse charge is what spoils our oil record. On one of our divisions, where we have the poorest oil record for lubricating oil, we only get sixteen miles per pint of lubricant. On the same division the individual records of the engineers the roundhouse was drawing new waste at 6 cents per pound, and new oil for starting up the fires in the fire boxes. When his attention was called to it and he was asked whether it was not a little extravagant, he said, No, that it was the only way they had to start fires. I was asked, this week, by a gentleman who was traveling with me, why it was that whenever an engine started up that the engineer allowed the engine to make half a dozen revolutions before he opened the cylinder cocks. We observed this in case after case as we passed freight trains, side-tracked for the passenger train. The sidings being short, the freight trains had to start up before we could pull past. In one case we were so close we observed a deluge of water thrown out of the stack of the engine; after that the cylinder cocks were opened. The water having all gone out through the stack, the question naturally arose as to what was the use of opening the cylinder cocks after you had got rid of the water. The reason for opening the cylinder cocks first is to get rid of the water before it washes any of the parts of the steam cavities. There is nothing accomplished by opening the cylinder cocks after the water has all been blown out through the stacks; we simply waste steam, and consequently, coal and power. Traveling engineers should look after this. MR. M. E. WELLS (Master Mechanic B. & M., Sheridan, Wyo.): I find, from my experience in the shops, that men get pedestal braces and oil cellars down and, having a great deal of trouble getting them up, are constantly bringing them to the shop to have them planed off. This I am trip, it is necessary for it to heat up sufficiently to melt this valve oil, and I believe that this is the source of a great deal of trouble to enginemen. Another thing is the habit enginemen have of raising waste off the top of the box with the oil can spout. All this does is to allow dirt to get closer to the oil hole and go down onto the journal. The waste is put on the top of the driving box as a filter, and should be left alone. If it gets a little gummy and sticky, a small quantity of coal oil will loosen it up so oil will penetrate through it. It has occurred to me that driving brasses are bored out too much in the crown in order to get the lips of the brass at or below the center of the driving journal. I am quite sure it is not necessary for the brass to bear at or near the center of the journal, and if this is true, there is no reason why the brass can not be bored, leaving as much as possible in the crown. I am aware of the difficulty of calipering the size of the journal in the brass, but this difficulty is overcome very easily by driving a stick of babbitt endwise in the box, so that you can caliper the size of the journal from the crown of the brass to the tool mark in the stick of babbitt. This is the practice on the Northern Pacific, and I believe is a very good one. On the subject of lubrication I want to speak about the expansion plates that connect the boiler with the frames. From the lubricating standpoint, these things are very much neglected. They should be oiled thoroughly, and when put up in the shop, should be carefully fitted, in order to allow an easy sliding motion when the boiler expands and contracts. I have expressed the idea recently that the sticking or moving hard of these expansion plates might possibly put a strain on the main frames that would help to break them. Some men I have advanced this idea to I find that the fellows who are always have thought there was nothing in it, pouring valve oil on the top of the driving while others, after a little thought, were boxes are always having lots of trouble, led to believe there was something in it. and this is how their trouble occurs. The Personally, I am quite sure that it can valve oil being placed on the top of the be a possible cause of broken frames. I box will undoubtedly help some while the have seen expansion plates stick so tight box is hot, but the engine going into the and refuse to move that they have broken roundhouse and standing over night will the expansion plates. You are all familgive a chance for this oil to get cold, and iar with the large amount of trouble from it practically makes a mat-an impenetra- the studs in the boiler that hold the exble mat-of valve oil and waste over the pansion plates, due, I think, directly to top of the box, and, in many cases, fills the fact that these plates are not propthe oil hole with cold valve oil. Whether erly fitted, and largely because they are the box is packed from the bottom, or in not lubricated. It has been explained to the cellar or not, before the brass can get me recently that these expansion plates any lubrication from the top on the next being tight and not allowing for the proper expansion of the boiler, would make an engine ride very hard. : MR. HIGGINS (Engineer of Tests on C., B. & Q.) The lubricator that we have today, to me, is a very poor piece of mechanism. First, you start the lubricator going. Before reaching the valve the oil must travel through a pipe some twen ty feet long, and all this space must be filled before the valve is lubricated. The engineer, when he starts out on the trip, allows so many drops a minute, and it does not matter if he is going twenty-five or forty-five miles an hour, he feeds just the same quantity of oil. It seems to me that a pump could be attached to the steam chest and arranged to pump a drop for a given number of strokes. This would give the oil directly to the valve and not be wasting when the engine was not moving. I had the pleasure of being in one of the large shipbuilding yards on the Clyde River, in Scotland, this last summer, and noticed that no lubricators were put on the engines. Upon inquiry I found that no oil is used to lubricate valves or cylinders, except a swab on the piston rod. They use dry graphite only, and will run for six or seven days continuously and experience no trouble. This matter of valve oil has become a large item, and it seems to me that some investigation with graphite will surely pay. If they can run a marine engine for a week without shutting down, without using oil, it seems as though we could, perhaps, use graphite in connection with oil and save this enormous cost of valve oil which now stares the engineer in the face every time he goes to draw a can of oil. MR. ROESCH: Mr. Wells spoke of putting plugs in driving box cellars. We tried that on the Colorado and Southern, putting one plug in each corner of the cellar. While it is a pretty fair device for packing the cellar, it is not a cureall by any means, and the trouble was to know if the cellar was properly packed. I believe if the cellars were properly packed with a perfectly spongy packing and then an oil pipe were put on, so that the engineer would pour oil into that pipe, and let it go into the cellar, that we would have much better success. In regard to the graphite proposition, I wish to state that we have been using graphite in connection with valve oil for lubricating cylinders for some time by means of an automatic graphite lubricator, but its success depends largely upon the location of the lubricator. If we do not get the lubricator located at the proper point much of the dry graphite is carried out through the exhaust-carried right out through the stack-but it has given us very good results as compared to oil lubrication. We use it dry. The lubricator is attached to the steam chest, and it holds about three-quarters of a pound of graphite and makes about 400 to 1,500 miles. It saves about enough in oil to pay for the graphite. But it was not put on with the intention of saving oil; simply to save cylinders. MR. C. H. KESSLER (Chief Draughtsman Colorado and Southern: The draw ing of the driving box (Figure 1) shows a central oil groove and also side grooves. It is not common practice to use both at once in the same box. We get the maximum pressure per square inch directly on top of the journal, and it would seem adwould add about 13 or 14 square inches visable to close up this cavity, as it bearing area. The side grooves are objectionable in that the oil must travel so great a distance in properly lubricating the rubbing surfaces, as it is evident from the drawing that the forward groove will be of very little benefit, when running forward, and conversely if running backward. In addition, there is the objectionable feature of the sharp edges scraping off the oil before it has a chance to do any good. The only way to lubricate driving journals, then, seems to be from below. There has recently been put in practice on one of the Eastern roads a device for lubricating driving journals with "dope." This scheme is illustrated in some of the technical papers, and consists essentially of a false cellar containing the "dope." A loose follower, actuated by a helical spring, forces the "dope" upward through the perforated tops of the false cellar, maintaining a thin film of grease on the journal. There can be little doubt but that hot driving boxes are caused by things other than great pressures and friction. Some of these other things that may be mentioned are the hammering due to the action of the main rods, poor counter-balancing, rough track, etc. Then there is hub friction to be taken into account. The hammer blows of the rods may be aggravated by loose wedges, loose brasses, etc. While we may always be troubled by hot driving boxes, some scheme whereby a lubricant may be introduced which has more body than the comparatively thin oils commonly used will greatly lessen the number." |