upr000329 115

Various disarrangements may take place in the mechanism o f the scale itself. A physical examination o f the scale w ill frequently reveal defects o f this character, and it is therefore essential, according to the testi­mony o f all those who have given this subject special attention, that the scale should be kept as clean as possible and that a frequent inspection should be made by goin g into the p it o f the scale. B y such examination defects can b e . frequently observed and corrected. A track scale much in use should be inspected and balanced every day. In the past, in the m ajority o f cases, the subject o f inspection seems to have received very scant attention. One witness testified that he regularly inspected the scale o f which he had charge by looking through a crack in the platform , and this is a fa ir specimen o f the manner in which that duty was often discharged. F o r this there is no excuse. I t is not possible to have an expert in charge o f every track scale, but i f the scale is properly installed a person o f ordinary intelligence can be readily taught to g ive it such care and examination from day to day as may be necessary, although this should be supplemented by an expert inspection at regular intervals. W h ile an inspection o f this kind is necessary and should never be neglected, since it may reveal sources o f error, the only certain w ay to determine whether a scale is accurate is by a w eighing test o f the scale itself. Th is test is made in various ways, but comes finally to the same thing, and consists in putting upon the scale a known w eight and then comparing the reading o f the scale w ith that weight. The w eight may be and is applied in various forms, but the most approved method and the one most generally in use is by the test car. F o r this purpose a car o f short-wheel base, usually 6 feet 6 inches, is provided, so constructed as to vary as little as possible in weight. A s a test car moves from point to point upon a railroad there is almost o f necessity some slight change in its weight, due to various causes, like the wearing away o f those parts which are subject to wear, the varyin g w eight o f the oil in the boxes, etc. I t was said, however, that a proper test car, properly used, would not va ry more than 50 pounds in a trip o f two weeks. Th e testing o f the track scale, when a proper test car has been pro­vided, consists merely in placing the car upon the scale and noting whether it weighs that car correctly. In order to make certain o f the correctness o f the test car itself, access must be had to a master scale; that is, a scale which has been tested by standard weights obtained from the Bureau o f Standards maintained by the United States Government. There should be one such scale upon every considerable railroad system. 12 IN T E R S T A T E COM M ERCE C O M M IS S IO N REPORTS. f 2S i. c. c. 1 I N RE W E IG H IN G OP F \ REIGHT BY CARRIER. 13 Considerable was said at the various hearings as to the period which m ight properly elapse between tests o f a track scale. E v i­dently much depends upon the care which is given the scale and the amount o f w ork which is required o f it. A scale subjected to continuous usage is, in the nature o f things, more likely to wear out than one which is used much less frequently. Th e general opinion seemed to be, however, that all scales should be tested by the test car at least once in two months; in many cases every month. Our investigations show that comparatively few railroads were, when this proceeding began, provided with proper test cars, and that in even few er cases were those cars put to frequent and efficient use. Th e railroad commission o f the state o f Minnesota is required by statute to w eigh certain commodities, and has jurisdiction in that connection over the railroad track scales o f carriers operating w ithin that state. W hen that commission first began its inquiries into the accuracy o f track scale weights and the operation o f track scales generally by the carriers, no railroad in the state o f Minnesota had a test car. Th e commission itself purchased one, and this has led the various carriers in that state to provide similar equipment fo r themselves. Certain railroad systems, o f which the Santa F e and the Pennsyl­vania are good illustrations, have given special attention to the cor­rect scaling o f cars, and to this end have attempted to install suit­able scales, to keep these scales in order, and to make certain that they are accurate. These railroads had at the beginning o f our in­vestigation test cars, but, broadly speaking, the test car was a thing, not unknown, but generally unused, and in a great measure this is still true. One o f the subjects most discussed in considering the testing o f scales was the degree o f accuracy to which a track scale should be expected to weigh. Track scales are usually. constructed to read w ithin 50 pounds; that is, one notch upon the scale beam represents 50 pounds. The, representative o f one scale manufacturing company testified that in his opinion a scale could not be said to be in good order until it would indicate the variation shown by a single notch upon the scale beam. U pon the other hand, many o f the carriers were o f the opinion that any such degree o f accuracy in a track scale was, as a practical matter, unattainable. W e are satisfied that a m odem scale, properly installed and kept in proper condition, should be accurate w ithin at least 100 pounds, and that when under test it shows a variation o f 100 pounds or more it should be considered out o f order. I t is not meant that the weight o f the contents o f a car can ordinarily be ascertained w ithin 100 pounds by track scaling. In to that result many sources o f error may 28 I. C. C.