amount. As the cylinders are tested at about 500 pounds pressure, they are quite capable of withstanding the pressure due to expansion of the gas occasioned by an increase in temperature. 225 cubic feet of Commercial Acetylene day, or at night, drop back an equal and will supply a headlight burner consuming one-fourth of a cubic foot of gas per hour, 900 hours; this would mean that on a locomotive averaging seven hours service per day, one charging of the cylinder would be sufficient to operate the headlight for 128 days. An engineer should know how many days a fully charged cylinder will furnish light, as if the gas is exhausted in less time it would indicate that one of the burners had been left open or that there was a leak in the tubing. By consulting the gauge he may always know how much gas is in the cylinder, and when the pressure becomes 6. The Burner.-The burner consists of a forked lava tip having holes arranged in such a manner that two jets of gas issuing from same meet at the center of the tip, producing the flame. Such a burner is shown in Fig. 3. The tip also has holes drilled into all sides for the purpose of admitting air, which mixes with the Acetylene gas as it issues from the tip. There is very little, if anything, about ing, complete with reflector, burner and this type of headlight to get out of order, chimney. consequently detailed explanations are unnecessary. The engineer should be careful to see that the burners are kept 9. The Headlight, Marker or Classification Lights, and Cab Lights.-Fig. 5 shows the parts required for the head Fig. 5. Parts required for Headlight, Marker or Classification Lights, and Cab Lights 7. Leaks. The presence of a leak may be readily determined by the smell of the gas, or if it can not be located in this manner use soap suds, but never use a light of any kind to find a leak. clean, and that all joints are tight and free from leaks. Crust or carbon never forms with pure gas. 8. The Headlight Cage, or Casing.Fig. 4 shows the headlight cage, or cas light, marker or classification lights, and cab lights. Those for the headlight are indicated as follows: 100°, cylinder; 101, stud valve (on cylinder); a later type of stud valve is known as 101°; 102, nut for stud valve; 103, nipple for stud valve; 106, key for stud valve; 111, inch steel tee; 112, 1-inch steel ell; 114, gauge; 138, 1-inch pipe; 313, flexible rubber tubing with end connections 318 and 319; 314, flange for gauge; 316, inch O. D. steel tubing; 317, regulating valve complete with inlet flange, 108, and outlet connection, 318; 319, special union (two); 113, 1-inch steel coupling. The extras required for marker lights are: 134, -inch couplings (two); 168, -inch pipe; 190, 3-inch lock nut (two); 240, 1/16-foot burner (two); 316, 1-inch O. D. steel tubing; 319, special union; 321, special tee (two); 322, special cock (two). The extras required for cab light are: 316, 1-inch O. D. steel tubing; 321, special tee; 319, special union (two); 322, special cock; 315, cab light complete, comprising inch coupling, 134; -inch pipe nipple, 168; -inch lock nut, 190; 1/16-foot burner, 240; and lamp case. The manufacturers advise that where a steel running board is used suitable plank should be provided on the underside of running board for securing equipment, or else equipment should be located close to rigid supports so as not to be affected by vibration of running board. Also that the cylinder should always be located away from source of heat, and that all high pressure threaded joints are to be tinned and soldered. Examination Questions and Answers. OIL, ACETYLENE AND ELECTRIC HEAD 1. LIGHTS. (Part 2.) Q.-What is acetylene? A. It is an illuminating gas, which is produced by combining calcium carbide with water. (Art. 2.) 2. Q.-How was the gas generated in the older types of acetylene headlights? A. The locomotive was provided with a tank containing a tray in which the necessary amount of carbide was placed; an automatic pressure regulating device permitted a small amount of water to drop on the tray, thereby generating the gas which filled the tank, and when it reached a certain pressure the water valve would close and the generation of gas would stop until the pressure was reduced. (Art. 2.) 3. Q.-How is the gas generated for use in the modern acetylene headlight? A. Instead of being generated directly on the locomotive a central station is established where the gas is generated, washed, compressed and stored in suitable holders, the holders after charging being attached to the running board or in some other convenient location about the locomotive. (Art. 5.) 4. Q.-Of what does the standard equipment of the Commercial Acetylene headlight consist? A. It comprises, in addition to a headlight cage or casing, a reflector, burner and chimney, a steel cylinder (Art. 5) for storing the gas, a regulating valve, a gauge, and the necessary small steel tubing for conveying the gas to the headlight and other lights about the locomotive as desired. (Art. 4.) mercial Acetylene does one of the steel 5. Q.-How many cubic feet of Comcylinders contain when charged? A.-225 cubic feet. (Art. 5.) 6. Q.-How long will one of these cylinders when charged supply a headlight burner consuming one-fourth of a cubic foot of gas per hour? A.-900 hours. (Art. 5.) 7. Q.-With a headlight burner consuming one-fourth of a cubic foot of gas per hour, how many days would a cylinder containing 225 cubic feet of Commercial Acetylene supply the headlight on a locomotive which averaged 7 hours per day? A.-128 days. (Art. 5.) 8. Q.-Is it necessary that an engineer should know how many days a fully charged cylinder will furnish light? A. Yes. Because where the gas is exhausted in less time it would indicate that one of the burners had been left open or that there was a leak in the tubing. (Art. 5.) 9. Q.-How may the engineer always know how much gas is in the cylinder? A. By consulting the gauge. (Art. 5.) 10. Q.-If upon consulting the gauge attached to a newly charged cylinder or holder it registered more than 150 pounds pressure, would there be any occasion for alarm? A. No, as the increased pressure is due to the expansion of the gas through increase in temperature, which on a warm day may amount to 20 or 25 pounds, the increased pressure dropping back an equal amount in the cooler part of the day or at night, and the cylinders are quite capable of withstanding such increased pressure. (Art. 5.) 11. Q.-Describe the burner used with the acetylene headlight. A.-It consists of a forked lava tip having holes arranged in such a manner that two jets of gas issuing therefrom meet at the center of the tip and produce the flame. Holes are also drilled into the sides of the tip so as to admit air which mixes with the acetylene gas as it issues from the tip. (Art. 6.) 12. Q.-How may a leak of the gas be located? A. By the smell, or if not in this manner, use soap suds, but never use a light of any kind. (Art. 7.) 13. Q.-What points about the acetylene headlight equipment should be observed by the engineer? A. He should be careful to see that the burners are kept clean of dust, and that the joints are tight and free from leaks. (Art. 7.) Technical Contributions SOME UP TO DATE AIR BRAKE ADVICE (Freight Train Service) BY WILL W. WOOD We've got a lot of new Mikado type engines big as they make 'em-superheaters, of course, and they carry 170 pounds boiler pressure. They are limited to 75 cars on one division, while in another district that is the minimum number of cars usually hauled in one train. These engines have but one 11-inch air pump, and in connection with the present ET locomotive-brake equipment there is an advantage in not increasing the aircompressing capacity. The problem of operating all-air successfully on long freight trains must be met first, in any instance, by close terminal inspection of the air brakes on the cars and the elimination of all leaks that can be detected by sound; and cutting in and operating practically all of the brakes in the train-for the higher the total percentage of the braking power in the train the less amount will the air pressure in the long and voluminous brake pipe have to be reduced in making service applications. It is a fact that, no matter how well equipped a road may be with air-brake inspectors in the terminal yards, in the hurry to get trains out without delay, as soon as the regular working pressure of air is pumped up that train is going to be shot out of the yards instanter-regardless of the leaks which will interfere with proper braking conditions on the road. With but one 11-inch pump, the leaks have got to be closed before the train leaves. Another thing put two 11-inch pumps on an engine; the first time one of them plays out, you report it when you get in and if the air-brake repair men are otherwise busily engaged you will not get your pump attended to; you will be met with the reply that "you got along for years with one 11-inch air pump, and it's strange you can't make one trip now without two pumps. G'wan! Pump 'll be attended to when you get back;" and before long most of the double-pumped engines will be running with but one pump in operative condition. If you have only one pump it has got to be kept in working order. This is one reason why it is more practical to use one Four Cylinder Cross-Compound pump than two pumps of smaller size. Now, just as soon as these big engines commenced doing business with their 75plus-car drags there was complaint from most of the engineers that the air pumps on the Mikado's "had something the matter with them;" in charging up a long train the pumps would settle down to a leisurely gait with an even stroke that could not be hurried up; that the pumps had no "ginger" in their action; and in some cases where the engineers made a stand for full air pressure before pulling out, from one-and-one-half to two hours time elapsed after cutting in to the train until the air pressures were at the normal "70 and 90"-the air pumps jogging soldierly along. In one such case where the air-compressing event had been in progress for an hour or so with indifferent results as to pressure increase, on one of the new engines-ET equipment, and a train of 75 cars-this engine was temporarily detached and another engine with the common, automatic brake equipment and an older and worn air pump-11inch-was coupled to the train in a trial to see what she could do in raising the pressure; and her pump was quicker in action, the brake-pipe pressure began to rise immediately and in about fifteen minutes the gauge showed 70 pounds. In every case of such slow pump action and the consequent delay in getting the brake pipe charged on long trains, I found that at the same time an excess pressure was being maintained; for instance, the pressures would be say 55 pounds brake-pipe and 75 pounds mainreservoir, yet it was known that the feed valve was adjusted at 70 pounds and was in good working order. After pushing the automatic brake-valve handle to release position the pump would at once |