ITM3579993 Weighbridge Test Wagon no 3453-Weighbridge test wagon Dept No

A scale test car is a type of

railroad car A railroad car, railcar ( American and Canadian English), railway wagon, railway carriage, railway truck, railwagon, railcarriage or railtruck (British English and UIC), also called a train car, train wagon, train carriage or train truck, is ...

maintenance of way Maintenance of way (commonly abbreviated to MOW) refers to the maintenance, construction, and improvement of rail infrastructure, including tracks, ballast, grade, and lineside infrastructure such as signals and signs. Track The most fundamen ...

service. Its purpose is to calibrate the

weighing scales A scale or balance is a device used to measure weight or mass. These are also known as mass scales, weight scales, mass balances, and weight balances. The traditional scale consists of two plates or bowls suspended at equal distances from a ...

used to weigh loaded railroad cars. Scale test cars are of a precisely known weight so that the track scale can be calibrated against them.

Purposes

Cars are weighed for various purposes. These include:

Axle load limits

Cars are weighed to ensure they are within the

axle load An axle or axletree is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In the former case, bearin ...

limits of the railroad.

Customer billing

Cars are weighed to determine (by subtracting the car's unloaded, or

tare weight Tare weight , sometimes called unladen weight, is the weight of an empty vehicle or container. By subtracting tare weight from gross weight ( laden weight), one can determine the weight of the goods carried or contained (the net weight). Etymo ...

from the total

weight In science and engineering, the weight of an object is the force acting on the object due to gravity. Some standard textbooks define weight as a vector quantity, the gravitational force acting on the object. Others define weight as a scalar quan ...

) the amount of cargo loaded. This is used to bill the railroad's customers for the carriage of bulk commodities, so it is essential that the track scales be accurate.

Construction

Many scale test cars were small, old railroad cars carrying heavy metal weights as their superstructure. Scale test cars needed special handling so they would not suffer damage, which might alter their weight. They were reweighed periodically on accurate scales at the railroad's shops.https://www.ams.usda.gov/sites/default/files/media/WeighingHB.pdf

References

Bibliography

*AAR, Engineering Division, "AAR Scale Handbook (2011)" *USDA, AMS, Grain Inspection Packers and Stockyards Administration(GIPSA), "Weighing Handbook" Chap. 3, Pages 31 thru 34, 27DEC2010 (Overall Document dated: Apr 2014) Retrieved: 08JUN2020

External links

NIST The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical sc ...

br>circa 1913 scale test car and its transporter rail car
One of its large calibration masses can be seen being hoisted onto the scale test car. Maintenance of way equipment Mass Measuring instruments {{Rail-transport-stub