degrees)?

A. If the feed water is heated much above 100 degrees it will not condense enough steam in the injector to cause it to work properly. Some injectors will work hotter water than others. It would also spoil the paint on the tank if heated to a much higher temperature.

68. Q. At 200 pounds pressure per square inch, what is the pressure per square foot on the sheets of a boiler?

A. About fifteen tons.

69. Q. What is the total pressure on the fire-box of a large locomotive?

A. Over 3,000 tons.

70. Q. Give a practical definition of heating surface.

A. The heating surface of a boiler includes all parts of the boiler and tubes that are directly exposed to fire or heat from the fire and are surrounded by water.

71. Q. Should an engine be slipped to get water out of the cylinders or steam passages?

A. No; the water should be worked out by opening the cylinder cocks and starting the engine slowly.

72. Q. What does it indicate when the smoke trails back over the train and into the coaches after shutting off?

A. It indicates poor firing or a lack of understanding between the engineer and fireman in regard to where the engine was to be shut off.

73. Q. Before shaking grates or dumping the ash-pan, what should be observed?

A. That the engine is not passing over bridges or cattle guards, crossings, switches, interlocking fixtures, or in yards. Fire on the track should be extinguished promptly at places where ash-pans are cleaned.

74. Q. Which is easier and more satisfactory on a long run, to stop and clean the fire if necessary or to continue to the end of a long, hard trip with a dirty fire?

A. Stop and clean the fire if necessary. It will save fuel and labor during the remainder of the trip and may also save an engine failure.

75. Q. Should you examine the flues to see if they are stopped up and leaking, and inspect the grate and grate rigging carefully before leaving the engine at a terminal?

A. Yes, so they can be reported if necessary. Clean flues and grates working well make a vast difference in the success of a fireman, and a great many engine failures could be avoided by keeping the flues and grates in proper condition.

76. Q. How should cab lamps, signal lamps, oil cans and lanterns be cared for?

A. They should be kept clean, free from leaks and always filled and ready for service before leaving terminals.

77. Q. About how many drops in a pint of valve oil when fed through a lubricator?

A. About 4,500 drops.

78. Q. Assuming that five drops per minute are fed to each of two valves and one drop per minute to the air pump, how many hours would be required to feed one pint of valve oil?

A. About eight hours.

79. Q. Assuming that the engine is running twenty-miles per hour, how many miles per pint would be run?

A. About 160 miles per pint.

80. Q. How many drops per minute should ordinarily be fed?

A. This will vary with the size of the locomotive and the work to be performed. On small yard engines one drop per minute for each cylinder is usually sufficient and one drop for the air pump every two or three minutes. This depends on the condition of the pump and the service being performed. For large engines in slow freight service four to five drops per minute, and for large engines in heavy fast passenger service from five to seven drops per minute should be fed. Air pumps in freight service where the brake pipe is in moderately good condition can usually be run with one or two drops per minute when handling long trains of cars equipped with air brakes.

81. Q. Will any bad results ensue from filling the lubricator full of cold oil?

A. Yes; when the oil gets hot it will expand and may break the glass or bulge or burst the lubricator.

82. Q. If a sight feed gets stopped up, how could you clean it out?

A. Close the water valve and the regulating valves to the other feeds. Open drain cock and draw out a small quantity of water so as to bring the oil in top part of lubricator below the top end of oil pipe leading to feed arm, then open wide the regulating valve to feed that is stopped up and the pressure from the equalizing tube will force the obstruction out of the feed nozzle and up into the body of the lubricator. Next, close this regulating valve until the feed glass fills with water, then open water valve and start feeds.

83. Q. How would you clean out chokes?

A. First, shut off boiler pressure and condenser valve; next, remove feed valve bonnet, then open main throttle valve, when the steam from steam chest will blow back through the choke plug, clearing it of any obstruction.

84. Q. What is superheated steam?

A. It is the saturated steam separated from the water from which it is generated with more heat added, increasing its temperature from 100 degrees to 250 degrees Fahrenheit above the saturated steam temperature.

85. Q. What is the advantage of superheating or increasing the temperature of the steam?

A. By increasing the temperature of the steam the volume of a given weight of steam is increased and all losses due to cylinder condensation are eliminated, which result in a reduced steam consumption, a saving in coal and water and increased boiler capacity.

86. Q. How is the increased temperature obtained by the use of the superheater?

A. By admitting the saturated steam into a partitioned receiver which has a number of 1½-inch pipes attached to it. These are located in and extend nearly the full length of the large flues, the steam having to pass through these 1½-inch pipes on its way back to the receiver, absorbs the heat from the gases passing through the large tubes, causing its temperature to rise, or in other words, become superheated.

87. Q. How much is the volume of steam increased by superheating?

A. For each 100 degrees of superheat added to saturated steam, at temperatures ordinarily used in locomotive practice, the volume of a given weight is increased roughly from sixteen to seventeen per cent.

88. Q. Why is the superheated steam so much more economical on coal and water than the saturated steam?

A. Because for a given amount of water evaporated you can increase the volume of steam 33 per cent. by superheating. It is readily seen that the coal does not have to be burned if the steam used has 33 per cent. more volume for filling space, or in other words, only so much steam can be admitted to the cylinders for every movement of the valve, and what can not be used must remain in the boiler, so if the engine can not use all of the steam that the boiler is capable of generating, the saving must show in coal and water. If you can not use all of the steam you do not have to burn coal to make it.

89. Q. Which is the better practice, to close the feed valves or water valve while waiting on sidings, etc.?

A. Close the feed valves; the water valve may leak.

90. Q. How can you tell if equalizer tubes become stopped up or broken?

A. If they were stopped up the equalization would be destroyed, and when the steam-chest pressure was less than the boiler pressure the feed would work too fast, the oil would enter the feed glass in a stream instead of forming into drops. If they were broken, the lubricator could not be used. The auxiliary oilers would have to be used to lubricate the cylinders.