MOVEMENT OF TRAINS By G. E. COLLINGWOOD re Single and Double Train Orders. Several letters which have been ceived this month indicate that the difference between the single and the double train order system is but little understood. There is also an interesting history connected with the growth of the double train order system, but space forbids any attempt to fully record it at this time. The single train order system is being used to considerable extent upon the smaller lines at the present time, but prior to the advent of the Standard Code of Rules the single order system was the principle system in use. When the Standard Code was formed in 1887 the double train order system was made standard and its use has rapidly increased since that time. movements which may be put in an order to three. This all has a tendency to reduce complications and overcome the one valid objection to the double train order system. In dispatching trains under the single order system the train addressed is seldom named by its number. For example, No. 4, a superior train, is given order No. 1 at A, reading "Meet No. 1 at B, No. 3 at C, and No. 5 at D." From this it can be seen that the order which No. 4 holds contains nothing except that which No. 4 is required to fulfill. In the movement of the inferior trains in connection with this order the method would be as follows: No. 1 would be given an order reading "Meet No. 4 at B." No. 3 would be given an order reading "Meet No. 4 at C," and No. 5 would be given an order reading, "Meet No. 4 at D." From this it can be seen that each train order contains only information for the train addressed. In the double order system only one order would have been issued for the movement and it would have been given in the same words to all trains affected; thus; "No. 4 meet No. 1 at B, No. 3 at C, and No. 5 at D." It can be easily seen that the order is equally binding on all concerned, but the inferior trains in this case receive much information which does not concern them, but which nevertheless they must keep before them. For example, the order contains three meeting points but only one of them affects the inferior train receiving the order. This being the case great care must be exercised to prevent the wrong meeting point from being associated with the superior train by the crew on any one of the three inferior trains. This is the weakness of the double order system, but by limiting the number of movements and insisting that an order shall contain no movement which does not directly affect the train first named, many complications of the double order system may be overcome. The single train order system is a method of train dispatching in which the instructions for the movement of trains are given to the superior train first; the order being addressed to that train only. The order is addressed to the superior train in the same manner in which the Standard Code requires a train order to be addressed, but inasmuch as the order is only given to the superior train the train addressed is seldom mentioned in the body of the order. In general practice the order to the superior train contains several movements which are afterwards given separately to the inferior trains concerned, but in totally different language. It is this fact which constitutes the chief merit of the single train order system. A train receiving an order under the single train order system has little or nothing at all in the order which does not directly affect it. In the double order system trains frequently receive much information in an order which has no reference to the train receiving it at all. This is especially true when long orders are given as is the practice on some lines. However, there is a strong movement on foot to so limit double or- The weakness of the single order sysders that they will not contain so many tem rests in the fact that the train dismovements. On some roads this is being patcher can very easily associate the accomplished by requiring that an order wrong meeting point with one of the inshall contain no movement which does ferior trains, especially where the businot directly affect the first train named; ness is heavy, or where the dispatcher on other roads the rules provide that only attempts to depend upon his memory. two movements shall be put in one or- Another bad feature of the single order der; other roads limit the number of system is the changing of meeting points, especially where the order to the superior train has been changed once or twice before it is given to the inferior train. Fully considering both systems, the double order system, under proper regulation as indicated above, is much less liable to produce misunderstanding or error, for the reason that whatever in an order takes away the right from one train confers it upon another in the same words. For example, an order reading "No. 1 run 45 minutes late A to B" is authority for any train receiving it to use the time stated, and it is also authority for No. 1 to run 45 minutes late. If the same order was issued under the single order system it would be given to No. 1 as follows: "Run 45 minutes late A to B," and it would be issued to an inferior train in the following language: "Use 45 minutes of No. 1's time between A and B." given a train which does not directly affect that train. This is partly true, but it must be taken into consideration that with the double order system the order is only sent once by the dispatcher, all trains concerned being addressed at the same time; therefore, it would seem that the matter of time would be about evenly divided; at any rate there could not be much choice so far as the saving of time is concerned. In the examples given above the orders to the inferior trains contain but one meeting point, in the single order system, but in actual practice it is probable that the order to the inferior train would also contain a meeting point with No 6 and No. 8; or time on No. 12, or some other superior train. Much good may be accomplished and many chances of misunderstanding eliminated if those who are interested in train orders would use their influence in favor In considering train order systems, of train orders which contain not more time is an important factor, and it is than three movements, and which conclaimed by some that the single order tain nothing that does not directly affect system is much the shorter as nothing is the train first named. Questions and Answers Locomotive Running and Repairs Answers by F, P. Roesch. 2383. Distinguishing Features of Locomotives. "State the main distinguishing features of the following locomotives: American or eight-wheeled: Mogul: tenwheeled; Consolidation; and Pacific.”— H. F. signed for, but other than calling it a power tank and deriving its power from the engine proper, he could give me no information. If you could oblige me with any information concerning same through the Magazine, it would be greatly appreciated."-J. F. B. Answer. The tender in question was no doubt that intended for the Triplex Answer. The distinguishing features locomotive constructed for the Erie Railof the American, or eight-wheeled loco- road, and which was illustrated and demotive, are that it has a four-wheeled scribed in the July issue of the Magaengine truck and two pairs of coupled zine. In this construction, the weight of drivers. The mogul engine has a two- the tender is utilized as adhesive weight, wheeled engine truck and three pairs of so as to increase the tractive power of coupled drivers. The ten-wheel locomo- the locomotive. Otherwise, the tender tive has a four-wheeled engine truck and serves the same purpose as any other three pairs of coupled drivers. The Con- tender; that is, a vehicle for carrying solidation has a two-wheeled engine coal and water to be used by the locotruck and four pairs of coupled drivers, motive. By the use of the engine on and the Pacific type has a four-wheeled which the tender proper rests, however, engine truck, three pairs of coupled it not only carries the coal and water for drivers and a two-wheeled trailing truck. the locomotive the same as does an Under the Whyte system, the engines ordinary tender, but it becomes selfwould be designated as 4-4-0 for the American; 2-6-0 for the Mogul; 4-6-0 for the ten-wheel; 2-8-0 for the Consolidation; and 4-6-2 for the Pacific. 2384. Support of Boiler.-"At what point is a locomotive boiler rigidly secured, and why?"-H. F. Answer. It is necessary to secure the boiler rigidly to some portion of the locomotive, and as one end of the steam pipes conveying steam from the boiler to the cylinders is attached to the boiler and the other end to the cylinder saddle, it naturally follows that in order to avoid vibration and possible leakage of these steam pipes the boiler should be secured rigidly through the cylinder saddle. The expansion of the boiler is taken care of by letting the rear end rest on sliding bearings, or flexible connections between boiler and frame. propelling and has a sufficient reserve force to assist in the propulsion of the train. The cylinders under the tender obtain their steam from the exhausts from the left high-pressure cylinder located under the locomotive proper, as will be quite clear on consulting the article referred to. 2387. Increase in Pressure.-"How much of its stroke would a 10-inch x 12inch (12-inch stroke) pump lose before 180 pounds pressure could be had in the cylinder, the cylinder being air-tight with an air gauge on it?"-R. J. L. the space Answer. This pressure can readily be calculated by following Boyle's Law, namely, that the pressure of a gas at a constant temperature varies inversely as In the present it occupies. instance, it is assumed that the pump cylinder contained atmospheric pressure, namely, 14.7 pounds per square inch, and that the pump piston is moved forward until the air contained in the cylinder has been compressed so as to show the gauge pressure of 180 pounds. started with atmospheric pressure in the must likewise add atmocylinder, we spheric pressure to the gauge pressure in order to determine the absolute pressure. Consequently, when the gauge showed 180 pounds, the absolute pressure would 2386. Locomotive Tank.-"I saw a tank equipped like an engine. It had be 194.7 pounds. Now, as the pressure cylinders and driving rods, and was for the Erie Railroad. I asked an engineer what it was, and what object it was de 2385. Pedestal Binder.-"What is a pedestal binder and its purpose?"-H. F. Answer.-A pedestal binder is a brace connecting the lower ends of the pedestal or frame jaws together. Its purpose is not only to bind the frames together at that point, but also to serve as a support for the shoe and wedge. As we rises inversely with the space the air occupies, dividing 194.7 pounds by 14.7 pounds, would give us the number of area times 14.7 must be compressed in order Therefore, 21 holes of the same to raise the pressure to 180 pounds would be equal to 7.77 square inches. gauge pressure. This we find to be equal The area of the 4-inch hole is found in to 13.24. In other words, the original the same manner, and is found to be measure of air contained in the pump equal to 17.72 square inches; therefore, cylinder must be compressed to 1/13-24 of the combined area of the 21 11/16-inch its original volume. As the diameter of holes plus the 4-inch hole is equal to the cylinder remains the same, it is not what diameter of single nozzle would be In order to find 25.5 square inches. necessary to take this into consideration; therefore, 1/13-24 of its original volume equal to, or would have an area of 25.5 square inches, we must extract the would be equal to 12 inches divided by square root of the area and multiply this 13.24, which is 9/10-inch nearly. Conby 1.128. The square root of 25.5 is sequently, the piston would lose 11 1/10 5.05, and this number multiplied by 1.128 inches of its stroke, or, in other words, would be within 9/10 inch of the comple- were drilled through the nozzle tip as equals 5.696. Therefore, if the holes tion of its stroke before the pressure stated, the combined area of these holes would raise to 180 pounds gauge pres- plus that of the original nozzle tip would be equal to a single nozzle 5 7/10 inches in diameter, or roughly, 5 inches. sure. 2389. Joy Valve 2388. Area of Nozzle Tip.-"What is the area, or the size of the opening of a nozzle tip, main hole 4 inches in diameGear.-"What are ter and twenty-one 11/16-inch holes, the principal features of the Joy valve drilled down through the top and coming gear?"-F. G. McI. out on the inside of the tip about half Answer. The principal features of way from top rim to bottom of tip? The tip is about four or five inches long and is the Joy valve gear are simplicity of conflared at the bottom so the holes could be struction, reducing the number of weardrilled through top rim down and come ing parts; a stationary link; a constant out inside of the tip, and the exhaust, in lead; and a gear capable of a very close addition to going through the main 4- adjustment, and one that, owing to the inch opening goes through the twenty-one few wearing parts, will maintain this ad11/16-inch holes. What size nozzle tip justment. It is of the outside radial would this equal if the openings of the type and, consequently, readily accessitwenty-one 11/16-inch holes were figured into one main opening in tip, including ble for inspection, lubrication and rethe 4-inch hole? What is the twenty-one pairs. The gear consists primarily of a 11/16-inch holes equal to, or what is their area? Please figure this out in a manner and explain it in the Magazine so I can get the rule to figure other matters of this kind."-Member. lever, X, connected to a predetermined point, D, at the main rod, Fig. 1. The lower end of this lever is, in turn, connected at B to a lever, or link, similar to the union link employed on a WalAnswer. In order to determine what schaert-geared engine. The other end, A, size nozzle tip would be equal to the sum of this link, however, instead of being of the 21 11/16-inch openings plus the connected to the crosshead, as on the original 4 inches, we must first find the Walschaert-geared engine, is connected area of one 11/16-inch opening, multi- to some rigid point on the guide yoke ply that by 21, and add to the total the frame, or any other convenient location, area of the 4 inch opening. To find the point A being stationary, but conthe area of any circular opening, square nected by means of a pin, so that the the diameter; that is, multiply the di- point B is free to move up and down. ameter by itself, and multiply this by the At a predetermined point on the lever decimal .7854. When dealing with com- X, is located the point C of the upright mon fractions in cases of this kind it is lever, which corresponds to the combinaeasier to first convert the common into tion lever of the Walschaert valve gear. the decimal fractions. This is done by This lever is fulcrumed to the point E dividing the numerator by the denomina- in the link block pin, the link block movtor. Dividing 11 by 16 will give us the ing up and down in the link slot as the decimal .687 as the diameter expressed lever moves forward and back. The in decimals of the 11/16-inch hole. amount of this up-and-down movement Square this or multiply it by itself, and depends, of course, on the location of the only carrying out the fraction to three connecting point D, of the lever X at the figures gives us the decimal .472 as the main rod. Above the fulcrum point E square of the diameter. This multiplied is the connecting point F for the valve by the decimal .7854 gives us the area, stem. The link is stationary when the which is 37 square inch, which equals locomotive is moving in any direction, the area of one 11/16-inch hole. the only movement imparted to the link being that given by means of the reverse lever when it is desired to reverse the engine, or to alter the cut-off, the point G showing the connecting point of the reach rod. The amount of travel of the valve, therefore, depends on the angle at which the link is placed, as with the reverse lever at a central position in the quadrant the curved slot of the link is practically vertical. Consequently, as the point F moves up and down, it will have very little effect so far as moving the valve stem forward and back is concerned. When the top of the link is moved either forward or back, however, by means of the reverse lever, the upand-down movement of the point F will have the effect of moving the valve rod forward and back, the amount of move from a single point, namely, the point D (Fig. 1), any failure of any of the levers or any of their connecting points will naturally disable the engine on that side. Therefore, the only thing that could be done would be to disconnect and remove the broken part, block the back end of the valve stem at such a point in the link slot as to place the valve central over both ports; then make the usual provision for lubricating the cylinder, and proceed. 2391. Broken Vibrating Link, Joy Valve Gear. "What would you do if vibrating link, or combination lever, should break or become disconnected?"-F. G. Mcl. Answer. If either broke, proceed G О X Fig. 1. Joy Valve Gear ment depending altogether on the angularity of the link. In some forms of the Joy valve gear, instead of the curved link herein shown, another form of link, termed the "quadrant guide," is used, in which the link block, termed in that instance, quadrant block, slides. Its use is exactly similar, however, as that outlined in Fig. 1. This form of motion, which is a modification of the Hackworth gear, and is also in many respects similar to the new type of gear, called the Southern valve gear, lately placed on the market, has had quite an extensive use in England, although it never found very much favor in this country. The only objection that can be offered against the gear, however, is the uneven steam distribution produced by the up-and-down movement of the main wheels in the pedestals. 2390. Broken Fulcrum, Joy Valve Gear. "What would you do if the radius rod fulcrum broke?"-F. G. Mcl. Answer. As this gear is all driven same as directed in answer to preceding question. If only disconnected, would arrange to connect it up again, with temporary pins, if the original pins should become lost. 2392. Broken Reach Rod Arm, Joy Valve Gear.—"What would you do in case the reach rod arm should break or become disconnected?"-F. G. Mcl. Answer. In case it was disconnected, would connect it up again, using any kind of a bolt or pin available. If the arm was broken, would clamp the link in the position intended to move, viz., if the engine were to be moved ahead, clamp the link in the forward motion, pointing far enough ahead so that you could be satisfied that the engine would start and handle her train with the link in that position. In case it was desired to reverse the motion of the engine it would, of course, be necessary to loosen the link, reverse it by hand, and again clamp in the opposite direction. |