the manipulation of a wheel-handle valve on the car floor, under a seat, as to convert the method of supplying the steam to that individual heating coil to the pressure principle, or the vapor plan, as desired. But in this arrangement the desirable simplicity of the straight vapor system is sacrified, and the trap valve is so increasedly complicated in construction that it is not generally approved of; it requires that all operatives-trainmen, inspectors, etc.-must be specially instructed in order to get the desired results, and which, as a fact, are seldom obtained, a car often being heated in one set of coils by the vapor plan and in another set by high-pressure steam; or one car vapor and another car high-pressure steam, etc. There are no good reasons for such a combination of the radically different methods of supplying steam for train heating; the straight vapor principle has been giving entirely satisfactory results when the temperature has been far below the Fahrenheit zero, as well as during those days in the early fall and late spring when only enough heat to just take the chill from the air is required-when by the pressure style of train heating the passengers are either roasted or chilled. Straight vapor is economical, and provides for an evenly maintained temperature. Examination Questions and Answers. TRAIN STEAM AND HOT-WATER HEATING. (PART 4, SECTION 1.) 1. Q.-State briefly what is meant by the term vapor heat as applied to car heating. A. It is a method of heating in which the steam contained in the heating coils is maintained at a pressure no greater than that of the atmosphere, or at the temperature at which water boils, namely 212 degrees F. (Art. 1.) 2. Q-Could the pressure in the steam train pipe increase the pressure in the heating coils above atmospheric pressure? A.-No. (Art. 1.) 3. Q.-Does it require any manipulation of the steam-heat valves or other attention on the part of the train crew to sustain this condition? A. No, it is done automatically. (Art. 1.) 4. Q. If a steam gauge were connected with one of the pipes of a heating coil in the vapor system, would it indicate any pressure? A. No, the gauge hand would stand at the zero pin. (Art. 2.) 5. A. Q.-Why is this so? Because there is always about 15 pounds of steam pressure in the heating pipes before the gauge registers any, this 15 pounds being balanced by the pressure of the atmosphere, and the ordinary steam gauge does not register absolute pressure but the pressure above atmospheric. (Art. 2.) 6. Q.-If upon approaching a terminal the supply of steam is shut off from the boiler and the end valve of the steam train pipe at the rear of the last coach is opened, will the steam be blown entirely from the heating system, and if not why not? A. No, a pressure of about 15 pounds per square inch will remain in the train pipe, this pressure being balanced by the opposing pressure of the atmosphere. (Art. 2.) 7. Q.-How long does this pressure remain in the heating pipes? A. As long as it remains steam, or retains sufficient heat to exist as a vapor. (Art. 2.) 8. Q.-As condensation reduces the steam below atmospheric pressure and its volume becomes less, what takes its place? A. The outside air, which rushes in through the opened train pipe and blow-off valves, and when the steam is completely condensed the steamheating system contains mostly air, with some water. (Art. 2.) 9. Q.-Upon arrival of the train at a terminal point, how may much of the trouble occasioned by freezing of the coupling gaskets together be prevented? A.—By the car inspectors immediately uncoupling the steam hose and hanging them up by the chains attached to the couplings. (Art. 3.) 10. Q.-Why is it necessary with any style of train heating by steam to maintain a high enough pressure in the steam train pipe, with all heating coils in the cars receiving steam through fully opened supply valves, that upon opening the rear train-pipe end valve there will be a good blast of clear steam from it? A.-In order to maintain a sufficient flow of steam to properly heat the rear cars. (Art. 4.) 11. Q.-Why is no valve supplied to the end of steam train pipe at the rear of the locomotive tender? A.-Because when the locomotive is detached from the train the steam is always shut entirely off at the main boiler valve. (Art. 5.) 12. Q. Why is the train-pipe end valve at the rear end of the rear car in the train nearly but not quite closed, when the others are fully opened? A.—In order that only enough steam may leak through it to keep the hose at that point from freezing up from lack of circulation. (Art. 5.) 13. Q.-Should the pressure in the steam train pipe ever be regulated by means of the main steam valve on the boiler? A-No, it should be kept fully open while steam is being supplied for heat ing the train, and the pressure supply should be corrected by adjustment of the regulating valve. (Art. 5.) 14. Q. When a signal is received to shut off the steam-heating pressure altogether, should it be done by closing the regulating valve? A. No, it should be left alone and the main steam valve on the boiler should be closed. (Art. 5.) 15. Q-When should the adjustment of the regulating valve be changed? A. Only when requested to do so by the trainmen or inspectors to increase or reduce the pressure. (Art. 5.) 16. Q-Why do some railroads use a safety valve attached to the steam train pipe on the engine? A. In order to blow off the excess pressure if through failure of the regulating valve the pressure in the steam train pipe became too high. (Art. 6.) 17. Q-At what pressure is the safety valve adjusted? A-A maximum pressure, varying on different roads, and which is presumed to be the highest that the hose will stand without bursting. (Art. 6.) 18. Q-Why is it best to discard the safety valve and, in case of failure of the regulating valve, govern the steam-heating pressure by hand manipulation of the main boiler valve for the rest of the trip? A. Because with a very long train, in order to provide the minimum 20 pounds on the rear car, the steam supply from engine to the train pipe of the first car might possibly exceed the adjustment of the safety valve. (Art. 6.) 19. Q.-What steam-heat regulating valves are most commonly used? A.-The Mason and the Gold. (Art. 7.) 20. Q.-With any style of steam heating, what should be the minimum pressure in the steam train pipe of the last car? A.-Twenty pounds. (Art. 8.) 21. Q. Can cars equipped with the vapor system be mixed with cars using the different styles of the pressure system? A. Yes. (Art. 9.) 22. Q.-When so mixed, does it make any difference in the operation of either? A.-No, so long as a sufficient pressure of steam is maintained in the train pipe, except that each vapor-equipped car in the train represents a minimum demand on the train pipe for its steam supply, and the more cars there are so equipped, the more train-pipe steam there is to spare for the heating coils of the cars having the pressure system. (Art. 9.) 23. Q.-Name some of the advantages of the vapor system. A. It is simple, economical, and provides for an evenly maintained temperature. (Art. 10.) Technical Contributions RELEASING A LONG FREIGHT TRAIN BY F. B. FARMER The following description of a quite serious accident that resulted from releasing the brakes on a long freight train at too low speed is very instructive and should be read with care and understanding by all enginemen who are desirous of maintaining a good record. break the train in two, in spite of the holding power of the engine brakes. The separation evidently occurred fifteen cars back of the engine. At the instant the hose parted the slack was, of course, out heavily on all The train consisted of 79 loads with the brake-pipe pressure was then mabut, probably, a few rear cars. Also, the heavier ones at the rear. It was at night and there was a dense fog. The terially above that in the auxiliary restrack was on a slightly descending grade. ervoirs in the forward portion of the The speed just previously was about 30 train, as must be at the time of releasm.p.h., and as the train was approach- ing. Under such a condition quick acing a point where the rules require abso- tion started when the hose separated, but lute control the engineer made a reduc- the higher brake pipe than auxiliary res tion of 10 pounds. His report stated ervoir pressure caused it to soon "peter that he released at about 18 or 20 m.p.h., out." Hence, at low speed, where brakes but this was obviously an error as to hold well, and with all slack out the forhave released at such speed under the ward brakes only applied quick action, circumstances related would not have probably ten or twelve cars each side of been safe, not "under control." How the separation. It was demonstrated in much lower the speed was when he re- 1886 with plain triple valves in the leased is not known, but he stated that "Burlington" brake trials, that without he held the engine brakes applied, that after running a few car lengths there was a jerk and that this was followed shortly by a jolt, as from slack running in. quick action the opening of the brake pipe will not cause the brakes to apply on a long train as fast as the slack will run. Hence, in this case the head end of the train "anchored" and the rear end Damage to the train was estimated at rammed into it before the rear brakes $1500.00, and important passenger trains could apply. The heavy loads at the were delayed 2 to 4 hours, not to men- rear end, probably with the slack tion delays to freight trains. The first bunched, acted as a battering ram. damage was to the fifteenth car back of There was no good reason for not the engine, and the last was to the six-stopping before releasing as it would teenth car ahead of the caboose. Be- have insured against a break-in-two, tween these points eight couplers were would have been safer in the dense fog driven in, the ends of the running boards at this point of possible danger, and the on some box cars were broken and one grade would have permitted of starting load was shifted. This was but part the train easily with but few minutes of the damage done. Why these very more time used than if it could have been severe results occurred is as follows: released while running without damage. The application of the train brakes With long trains that do not have K bunched the slack, as is usual, because triple valves on at least the twenty-five the head brakes always apply first. The forward cars engineers should be guided slack remained bunched because the in releasing by the following well-acpoorer-holding brakes were on the rear cepted instructions, noting particularly cars, due to the heavier loads in these cars. Therefore, when release was at- "At how low speeds brakes can be tempted the slack was in, the most un- released without liability of damage defavorable condition for releasing. The pends on how heavily they are then apearlier release of the head brakes caused plied, the amount of main reservoir presthe slack to run out severe enough to sure, the length of the train, whether the italicized portion: slack is then in or out, lightly or heavily, care for these varying conditions. Enand on whether track conditions (sags, gineers must exercise judgment in this, humps and curves) do or do not favor but taking all chances on the side of releasing. Plainly, no simple rule can stopping." LOCOMOTIVE SHOP WORK-HOW SOME OF IT BY F. W. BENTLEY, JR. Renewing Rod Brasses. The general renewal of all rod brasses is another phase of locomotive shop work to which much attention is also given as the engine passes through her periodical overhaulings. It is perhaps one part of the general repair work at which progress is made more rapidly than at any other, because of the fact that after the rods have been stripped and run over to the rod benches the work on them can proceed without the necessity up no matter how slightly or badly worn they may become. The operations in finishing and fitting them are perhaps worth a short general description. The rough brass is "chucked" or held at one end with just enough of the brass in the jaws to prevent the boring or turning tools from tearing it out of the machine, Fig. 1. While held in this manner the brass is bored out to a size of about 3/64ths of an inch larger than the diameter of the side rod pin it is to be used in AM BRASS CHUCK JAWs. Fig. 1 of any of the workmen being compelled connection with. After the brass has to wait on those of another department been bored out it is then turned down on for assistance or completion of any part of the work. The different types of brasses, together with the various methods used in fitting them up for application, are undoubtedly the source of some interesting facts to those whose work does not permit them a close observation of a systematic shop routine. The solid or one piece brasses are of course the easiest to finish from rough stock, and are at the same time the quickest to apply, but one feature about them is that it is impossible to key them the outside to a diameter of about 1/64th of an inch larger than the inside diameter of the hole for it in the end of the side rod. When these two operations are finished, the brass is removed, turned end for end, recentered and the small unfinished end of the brass turned off. The brass from one of its ends is then faced off to a width of about 1/32d of an inch less than the distance between the end collar and the back shoulder of the pin, shown by A in Fig. 2. Part of this operation is also the turning of the fillet, |