Study of Locomotive Whistles 113 



According to the company that manufactured it, the chime whistle 

 used in this investigation — a regular locomotive whistle — requires about 

 8,352 pounds of steam per hour when blown at 200 pounds steam pres- 

 sure. Locomotive manufacturers say that seven pounds of steam per 

 pound of coal is good average locomotive practice. This means a coal 

 consumption of 1,190 pounds of coal per hour, more than 18 pounds 

 per minute, approximately one pound of coal for every three seconds, 

 or two pounds for every time the whistle is blown — the series of blasts 

 for any signal aggregating, on the average, about six seconds. 



Observations are still in progress on the question of the fraction 

 of the time the whistles are blown. Considerable variation has been 

 found for different engine crews and different railway lines. So far 

 the average runs about two minutes per hour. Assuming this figure, 

 a locomotive equipped with such a whistle and operating it at the 

 indicated pressure requires some 36 pounds of coal and 140 pounds 

 of water per hour for whistling purposes only. 



There are in the United States, on Class A railroads alone, some 

 65,000 locomotives. Investigation is still in progress as to the actual 

 number in service at any one time. It is certain, however, that the 

 cost of blowing locomotive whistles runs into the millions per year 

 and that a considerable saving would be effected if a smaller whistle 

 could be substituted without sacrificing anything from the standpoint 

 of the efficiency of the sound as a warning signal. The experiments 

 herein described warrant the conclusion that this change can be made 

 and the whistle's signalling efficiency increased at the same time. 



It is a matter of common observation that locomotive whistles on 

 different roads, and frequently on the same road, differ greatly in pitch 

 and in quality. When one hears a whistle, frequently he can not tell 

 whether it is a locomotive whistle or a factory whistle. He becomes 

 so accustomed to hearing such sounds that they may call forth no mental 

 reaction whatever. If all locomotive and traction car whistles were 

 of one pitch and others were prohibited from using whistles of that 

 or near that pitch, the human ear would soon come to recognize that 

 tone and instinctively associate it with danger. Not only this, but the 

 volume of sound required to produce a mental stimulus would be greatly 

 lessened. The writer advocates a legal standard pitch for all locomotives 

 and traction car whistles, and legislation that will guarantee railway 

 companies its exclusive use. 



Waterman Institute for Research, 

 Indiana University. 



