Fairbanks 12-1492 - 12-1496 A.A.R. Combination Railroad Track/MTS - Manual (Page 11)

04/12 11 50538 Rev. 7
1-D: Regulations:
This Scale is designed and manufactured in accordance with regulations established by
Handbook 44 as adopted by the National Conference of Weights and Measures (NCWM), the
Association of American Railroads (AAR), and the National Institute of Standards and
Technology (NIST). If the Scale is intended to provide weights to the serving railroad for the
purpose of revenue, it shall be installed, repaired, tested, and maintained in accordance with
the Association of American Railroads Scale Handbook, which contains the rules and specifi-
cations for the construction and maintenance of track scales for the weighing of railroad vehi-
cles.
Excerpts from the Association of American Railroads Scale Handbook
Location: Scale shall be so located that an adequate foundation and at least 75 feet of
tangent track at each approach to the weighrails can be provided.
Elevation: In areas with poor drainage, the scale shall be raised to such an elevation that
drainage of the surface water shall be away from it. Means shall be provided to prevent
accumulation of water at the scale site. Solutions for saturated areas with poor drainage shall
be determined by a competent soils engineer.
Drainage: The pit floor shall be pitched to a common point for drainage and shall be
smooth and free from pockets in which water may stand. If the pit floor is below substrate
water lever, the pit shall be drained from its lowest point into a sump adequately equipped
with automatic means for removal of water as it collects.
Footing or Piers for loadcells: Concrete footings or piers supporting load cell base plates
shall not be less than 18 inches thick. Their tops shall be above the floor a sufficient distance
to prevent the accumulation of water around or under the base plates.
Pit floor: The floor of the pit may be a mat of concrete approximately as thick as that
required to support the load cell base plates or, if local conditions permit, the thickness may
be reduced to no less than 6 inches.
Ventilation: All scale pits shall be ventilated to meet the needs of each particular case to
minimize the relative humidity in the pit and to retard corrosion of scale parts and structural
steel.
Entrance to the Scale Pit: Suitable access to the Scale pit shall be provided. The entrance
shall be closed by a suitable closure fastened to prevent the entry of unauthorized persons.
AAR Scale Handbook
Safety Piers: Suitable piers, columns, or other supports should be provided to prevent
excessive drop of the girders if there should be a failure of other Scale parts. Clearance
should be maintained at full scale capacity.