Truck scale

A truck scale (US), weighbridge (non-US) or railroad scale is a large set of scales, usually mounted permanently on a concrete foundation, that is used to weigh entire rail or road vehicles and their contents. By weighing the vehicle both empty and when loaded, the load carried by the vehicle can be calculated.

The key component that uses a weighbridge in order to make the weigh measurement is load cells.

Commercial scales have to be National Type Evaluation Program (NTEP) approved or certified. The certification is issued by the National Conference on Weights and Measures (NCWM), in accordance to the National Institute of Standards and Technology (NIST), "Handbook 44" specifications and tolerances, through Conformity Assessment and the Verified Conformity Assessment Program (VCAP)

Handbook 44: General Code paragraph G-A.1.; and the NIST Handbook 130 (Uniform Weights and Measures Law; Section 1.13.) define Commercial Weighing and Measuring Equipment as follows;

weights and measures and weighing and measuring devices commercially used or employed in establishing the size, quantity, extent, area, or measurement of quantities, things, produce, or articles for distribution or consumption, purchased, offered, or submitted for sale, hire, or award, or in computing any basic charge or payment for services rendered on the basis of weight or measure.

NTEP approved scales are generally considered those scales which are intended by the manufacturer for use in commercial applications where products are sold by weight. NTEP Approved is also known as Legal for Trade or complies with Handbook 44. NTEP scales are commonly used for applications ranging from weighing coldcuts at the deli, to fruit at the roadside farm stand, shipping centers for determining shipping cost to weighing gold and silver and more.

A rail weighbridge is used to weigh rollingstock including railroad cars, railroad cars, goods wagons and locomotives, empty or loaded. When loaded, the net weight of the cargo is the gross weight less the tare weight when known. It is also used to weigh trams.

There are different types, but all of them have electronic sensors built into the track that measure the weight. All designs have in common that there must be a sufficient approach and departure distance in front of and behind the respective scale. All of them can measure independently of the direction of travel and whether the train is being pushed or pulled.