upr000329 117

16 INTERSTATE COMMERCE COMMISSION REPORTS. care, errors m ay result from this method o f weighing. Th is test, in view o f the manner in which it was conducted, convinces us that cars ought not to be coupled at either end when weighed, i f this, as a practical matter, can be avoided; and that is also the fa ir in fer­ence from the entire record upon this point. Some few railroads still weigh cars in motion when coupled at both ends; that is, the train is drawn slow ly across the scale and the w eight o f each car observed during its passage. Th is method o f w eighing aggravates all the errors and sources o f error which would be present i f the car were spotted w hile coupled at one or both ends. W h ile some o f the witnesses introduced tables showing the result o f experiments tending to prove that this method o f w eigh­in g was accurate, the opinion o f most o f those qualified to form one, and the practice o f all railroads where this subject has been given careful attention, condemns the w eighing o f cars in motion when coupled at both ends. Th at system o f w eighing m ay be fa ir ly desig­nated as a relic o f the dark ages o f track scaling. M any railroads have constructed at very great expense the most approved track scales, w ith a special view to w eighing cars in motion. The best o f these scales are provided w ith an arrangement called a mechanical hump, by which the car is slightly elevated and set in motion over the scale. B y this method a uniform speed across the scale is obtained. Th e car is absolutely disconnected from all other cars, and experiments appear to show that when the scale is properly constructed and properly operated accurate results can be obtained. I t would seem to be, in the nature o f things, impossible to w eigh a car while in motion w ith the same nicety that it can be weighed at rest, but it does appear that substantially accurate weights can be obtained in this manner. In actual life the ideal is not always attainable, and in practical railroad operation it may not be possible to weigh loaded cars by the most perfect method. Th e time and expense involved in these d if­ferent methods o f w eighing must be considered. Th e testimony tends to show that there are instances where cars can only be weighed in motion and that there are other instances where it would impose a very serious burden i f they were to be in all cases uncoupled. This record does not show the expense o f w eighing a carload o f freigh t. Th e opinion was expressed by one witness that it would cost 80 per cent more to weigh cars uncoupled than to weigh them coupled at one end. To-day i t is not so much a question o f additional expense as o f additional facilities. T o require all cars to be spotted fo r Weighing would render very extensive changes necessary at points where they could not w ell be made. 2 8 1. C. O. 1 I N RE W E IG H IN G OE F R E IG H T B Y CARRIER. 17 \ Our general conclusion is that cars should never be weighed ih motion coupled at both ends, that they may properly be weighed m motion when uncoupled upon scales especially designed fo r that purpose and in charge o f thoroughly competent men; that cars should not ordinarily be weighed coupled at one end, and never unless at points where the greatest attention is paid to the condition o f the scale and the competency o f the weighmaster. Th e second source o f error in the operation o f track scales lies m the observance and recording o f the weight actually registered by the scale. I t is necessary fo r the weighmaster to id en tify the car, that is, to take its initials and number, to ascertain the net tare weight stenciled upon the car, and to also ascertain and record the w eight o f the loaded car, as shown by the scale beam. W hen the car is spotted and uncoupled there is usually sufficient time fo r doing this w ith care, so that only occasional error results; but when the cars move across the scales with comparative frequency the liab ility to error is very much increased. So great is this liability, and so many errors arise from the personal infirm ity o f the operator, that much thought has been given to the perfection o f devices which shall eliminate this source o f mistake. There are to-day two general classes o f instruments fo r this purpose— the automatic and the mechanical self-registering device. Th e automatic device is attached to the scale beam, and stamps upon paper, without the intervention o f any human agency, the w eight o f the car as it would be recorded upon the beam itself. Th e only duty o f the weighmaster is to iden tify the car o f which the weight is taken. Assuming the device to be perfect in operation, the only liab ility to error arises from applying the weight recorded to the w rong car. W ith the mechanical self-recording device the operator observes the scale beam as the car passes across the scale or comes to rest upon the scale. When the beam is balanced he throws a lever-engaging mechanism, which records the w eight as shown by the scale. H ere the human element is present, since the operator must observe the moment at which the scale balances and throw the lever o f the recording contrivance. The w eight is recorded as o f the moment when the lever is thrown, so that an error in observing the scale beam or in pressing the lever results in an erroneous weight. The advocates o f these tw o contrivances have each much to say in fa vo r o f his invention. Scale makers who do not as a rule own the self-recording mechanism and who apply whatever one is desired generally agree that some device o f this kind should be used, and such seems to be also the impression o f most railroad men o f experience in these matters. There is, however, no agreement as to what device 28 I. C. C.