PROCEEDINGS OF THE SOCIETY OF ARTS FOR THE TWENTY-SEVENTH YEAR. MEETING 377. Heating Passenger Cars by Steam from the Locomotive. BY PROF. GAETANO LANZA. The 377th meeting of the SoCIETY OF ARTS was held at the Institute on Thursday, October 11th, at 8 P. M., President Walker in the chair. After the reading of the records of the previous meeting, the President introduced Prof. Gaetano Lanza, of the Institute, who read a paper on "Heating Passenger Cars by Steam from the Locomotive." Prof. LANZA first stated that the substance of his paper was taken from his recent report to the Railroad Commissioners of this State. He then said: While the railroad companies in this State are nominally using, as a rule, some one or more of the so-called systems, they have in many cases been trying the different appliances, more or less regardless of the systems, and the subject will be treated in this paper from the latter point of view, the different methods for accomplishing any one special object being discussed together, and not as forming a part of a certain so-called system. We may, therefore, classify the subjects to be considered as follows: : 1. The means of coupling the steam pipes of the cars together. 3. The means of disposing of the condensation. 4. The proper piping in the cars to give the necessary radiating surface, and freedom of circulation. 5. The proper valves to be used. 6. The disposition of the main steam pipe. 7. The use of live steam, exhaust steam, or water. 9. Means of regulating the heat in moderate weather. COUPLINGS. There is a large number of steam couplings in the market, each so-called system having a different one. Indeed, it might be said that the differences in the couplings form one of the most distinctive features of the systems. No detailed description of them is necessary, but the following distinguishing features should be mentioned :— While the greater part depend for flexibility on a flexible rubber hose, there are some which claim as a specially good feature that they are made entirely of metal. Such couplings depend for their flexibility upon ball joints and slip joints. Experience has shown that they wear out and leak badly in a very short time, so that this class of couplings may be pronounced unsuitable. A feature which exists in a number of couplings, and is undoubtedly good, is the property of automatically uncoupling whenever the cars break apart. This feature is enjoyed by the Sewall, the Westinghouse, and some other couplings. In this class, also, each part of the coupling is attached to a piece of hose attached to the main train pipe of each car, and these couplings should be, and generally are, interchangeable, each half being like the other half. The tightness in such couplings is insured by the force of gravity causing the rubber gaskets, which should be of hard rubber, or some similar composition, to press against each other. Such couplings need a certain length of hose, and, of course, form a pocket between the cars which might be supposed to collect condensation water, but which, as far as observed, does not present this difficulty. Some couplings consist of one piece of hose intermediate between two metallic portions to which it is permanently attached, so that this entire portion can be taken off without making up any joints. These couplings have either metallic surfaces in contact, or else rubber gaskets, and are usually made tight by means of a screw. If the train were to break apart they would not uncouple, but would have to break. Moreover, it does not seem probable that a metallic joint can be kept as tight as a gasket, unless it be more carefully handled than it is likely to be in the regular service of a railroad. In conclusion, it is very important that all those roads that are at all likely to interchange cars should adopt the same coupling, even though they have nothing else alike. The following considerations favor the adoption of the Westinghouse air-brake coupling: The train hands are all familiar with its management. The patent expires shortly, and the payment of royalty would be avoided. The three-quarter inch coupling, now used for the air-brake, would doubtless be too small, and it would be necessary to adopt the one and one half inch coupling. Also, it would be necessary to have the gaskets made of hard rubber or of some similar compound, and not of soft rubber. The Boston and Albany and the New York and New England railroads have already tried the Westinghouse couplings, and they work well. REDUCING VALVES. In regard to the means for reducing the pressure of the steam before it reaches the train, the most primitive way is to introduce into the pipe leading to the train an ordinary globe valve, and to require the engineer to regulate it by hand, so as to produce the proper pressure on the train. Some do this from choice, and others because they have been unable to find a reducing valve that did not get out of order. Some of those who use a globe valve add a safety valve, which blows off at a certain pressure, and thus warns the engineer that the globe valve wants attention. Nevertheless, the proper way to accomplish the object is to introduce into the pipe a reducing valve, which, when once set, will keep the pressure on the train uniform without the necessity of constant adjustment by the engineer. There are many reducing valves in the market, but when they are subjected to high pressures, and not handled with more than ordinary care, they too often fail. This failure is often due to their extreme delicacy, and to the difficulty in keeping lubricated certain parts which are exposed to very high temperatures and require specially good lubrication. These valves generally have some kind of flexible diaphragm, and the possibility of making such a valve succeed, under trying circumstances and long usage, is questionable. On the other hand, valves composed of pistons of different sizes have been tried, but not to any great extent, and the most that can be said is that there is promise of success in this quarter. TRAPS. The means of disposing of the condensation without letting it freeze, and thus burst the pipes or other connections, is one of the most serious questions of all those connected with steam heating. Even the so-called frost-proof traps freeze up at times. First, as to the object of any trap. In some of the so-called systems the steam is taken into each car from a cross or a T in the main steam pipe under or in the floor of the car, and that portion which condenses in any one car must be drained from that car, and does not pass into the next. Of course the draining can be accomplished by means of a simple globe valve, without any trap at all, but if this is done the following difficulties are met: If the valve is closed while the train is running, too much condensation water may collect before it can be let out, thus getting water into the main pipe and preventing a good circulation of the steam, and, at the same time, permitting the condensation to cool in the lower part of the pipe, and perhaps even freeze and burst the pipe. If, on the other hand, the globe valve is left open enough to avoid the above-described dangers, there is leakage and consequent waste of steam, and this may amount to a good deal, especially when the jarring of the train causes the globe valve to open wider during the run. These objections become serious on through trains, and in all cases where the times between stations are long and the stops short, and where the management of the valves is intrusted to green hands; but on roads where the times between stations are short, and where the work is only intrusted to well-drilled hands, the objections stated above are not valid. Thus on the Connecticut River road and on the Boston, Revere Beach, and Lynn there is no trouble of this sort, and traps could easily be dispensed with. Indeed, there is never any difficulty with frozen traps in the case of roads where the cars are kept warm all the time, whether running or standing still; but there is difficulty when cars have to be left for long periods in the cold with no heat supply. By the Martin, the Emerson, and several other systems, each car is drained separately. In the Sewall system the steam passes from the main pipe into a valve in the middle of the car. If this valve is wide open the whole, and if partly open a part, of the steam passes through the car back to the main pipe, from which the condensation may be drained off by a trap or by the globe valve if it is open wide enough. If the trap or valve is closed the whole of the condensation is forced back into the rear car, and from the end of the main pipe of the rear car it is blown out. This is the method most commonly used on the Old Colony and the Fitchburg railroads during the run, both of these roads using the new style Sewall valve. If the valve or trap is par tially open a part is disposed of in each way. When the old style valve is used they are more likely to depend upon the trap to drain the entire condensation of the car. When the condensation is all forced back, and globe valves are used instead of traps, it is customary to make use of the valves only on two occasions : (a). On heating up, to drain the condensation when the steam first starts through the car. (b). On putting the cars away, to drain the main pipe thoroughly, so as to avoid all danger of freezing. For these purposes the globe valve works much better than the trap, as the latter does not furnish a sufficiently free exit for the steam, and freezing ensues when the cars are exposed without heat. There is an increasing tendency with those who use the Sewall system to discard the Sewall trap and use a plain globe valve. This is done on the Fitchburg and on the Old Colony roads. The idea at the basis of most of the traps, whether those used to drain the main pipe or the car, is that the contraction and the expansion of some expansible metal or liquid, due to different degrees of temperature, shall respectively open and close the valve, thus opening to let out the water, but closing to keep in the steam. This is effected by causing the trap to close at a certain fixed temperature, which, if the steam in the car were at atmospheric pressure, would be 212 degrees Fahrenheit. The operation of the trap is supposed to be as follows: While the pipes are full of steam, so that the expansible metal is exposed |