592 Forestry Quarterly. 



and three-quarters bituminous coal, such as is ordinarily used in locomo- 

 tives. Test3 upon the Southern Pacific show an evaporation of about 

 twelve to fourteen pounds of water per pound of oil from and at 212 de- 

 grees Fahrenheit. Coal will evaporate about six to eight, at best, which 

 shows over 75 per cent, greater heat value. Furthermore, the same 

 boiler will evaporate at least 25 per cent, more water when burning oil 

 than when burning coal. In other words, as the speed of a train is limited 

 by tjie steaming capacity of the locomotive boiler, the locomotive will haul 

 the same train at a faster speed. 



8. Clogging. — There is an absence of clogging of the tubes from cin- 

 ders, especially those toward the bottom of the boiler. With coal, this is 

 a common cause of inefficiency in boiler operation, and unless cleaned fre- 

 quently, the steaming quality of the boiler is affected materially. With 

 oil, occasionally a slight soot will form in the tubes, due to incomplete 

 combustion in starting or while in operation, which can be removed quite 

 readily by means of a pail or two of sand. This is easily and effectively 

 done by admitting sand through the firebox when the engine is working 

 hard ; the draft will carry the sand through the tubes and all soot or 

 possibly tarry deposit will be scoured off by the abrasive action of the 

 sand particles. 



Disadvantages in Burning Oil 



1. Increased Firebox Repairs. — A coal firebox will last from five to 

 fifteen years (depending upon the water, etc.). Ordinarily, an oil firebox 

 will last two to five years. These figures apply to railway operation, and 

 will be increased when applied to logging locomotives, where the ser- 

 vice is much less severe and less continuous. 



2. Greater first cost of locomotive. 



Kinds of Oil 



There are three kinds of oil ordinarily used in oil burning locomotives. 



1. Crude petroleum, which is exactly as it is pumped from the ground. 

 It is not good practice to use this oil in its crude state, because of its 

 extreme volatility and the consequent danger from explosion when tanks 

 have to be examined, either for repairs or otherwise. In wrecks, crude 

 oil invariably would be set on fire. Another point is, the extremely naus- 

 eous odor, and, further, crude oil is not so economical as reduced oil, be- 

 cause it weighs approximately from six and one-quarter to six and one- 

 half pounds per gallon, while reduced oil weighs about seven and one- 

 quarter pounds. Since the thermal efficiency of any fuel depends upon the 

 weight, it is clear that crude oil has not so many heat units per gallon as 

 reduced oil. Therefore, crude oil in storage will evaporate quite readily, 

 due to the volatile constituents, while reduced oil is not affected at all, 

 practically speaking. 



2. Fuel oil or reduced oil, which is used in stationary plants and in some 

 locomotives, is obtained by reducing or refining crude petroleum. The base 

 of crude petroleum varies considerably in the different parts of the coun- 

 try, ranging from a paraffin base to an asphaltum base, and consequently 

 reduced oil will vary somewhat. The desirable features about oil used 

 in locomotives are comparatively high fire and flash tests. 



3. Residuum, which is largely used in California where tJie crude oil 

 has an asphaltum base and where very little refining into gasoline and 

 kerosene is done. It is there used commonly under boilers in stationary 

 plants, and to some extent, in locomotives in Russia. The residue of 

 Russian oil is utilized extensively, because it contains about 75 per cent 

 residue and 25 per cent, tefined oil. The average American oil on the 

 contrary, contains about 25 per cent, residue and 75 per cent, lighter oil. 



