26 BULLETIN 978, U. S. DEPARTMENT OF AGRICULTURE. 
for some time, when the material may have seasoned and dried out. 
The weights as found at such weighings are stenciled upon the side 
of the car and are used as the weight of that car until it is reweighed. 
Any repairs made by private shippers, any coopering that may have 
been done, any loss of doors or lining, or any other damages are not 
included in the stenciled weights. Snow or ice on the car will ma- 
terially affect its weight, as will also excessive moisture. 
It is therefore true that the stenciled weight frequently does not 
represent the current weight of the car, and net weights obtained 
when using stenciled weights may be incorrect to the extent of several 
hundred pounds. If stenciled weights are to be used as tare weights 
it should be known that no changes have been made in the car since 
it was last weighed and stenciled. 
A more satisfactory method of weighing by railroads would be to 
have the scales located at terminal markets and the loaded cars 
weighed as they are being switched to the warehouses and the empty 
cars weighed as they are taken away. Care would still be necessary, 
however, to keep the cars as free from snow, ice, trash, and other en-- 
cumbrances when weighing the empty car as when weighing the load. 
The weighmasters at some railroad track scales estimate the weight 
of any snow or ice that may be on the cars and add that amount to 
the tare weight, together with an allowance of about 150 pounds for 
the brakeman on the car when it is allowed to roll onto the scale 
from a hump or incline. A tolerance of from 200 to 500 pounds is not 
considered excessive in this class of weighing, and it seems doubtful 
whether such weights are sufficiently accurate to be relied upon as a 
basis for invoices or for claims for shortages or overcharges. 
The condition of the scales is also an important factor. Unless 
scales are kept in repair, free from snow and ice, and in balance, the 
weights obtained from them will not be accurate. Track scales are 
usually tested with a test car. This car consists of a collection of large 
test weights mounted upon a set of trucks and kept at a constant 
weight. Most railroad systems have a test car operating upon their 
lines continuously, which visits each scale about once each month 
Heating systems are also installed at many of the modern railroad 
track scales which keep the scales dry and free from ice and snow. 
PRIVATE TRACK SCALES. 
While the greater part of the hay unloaded at warehouses is 
weighed over platform or wagon scales, a number of dealers and ware- 
housemen have track scales at their warehouses, over which they 
weigh the commodities they handle. 
The same rules relative to the care of the scales that apply to wagon 
scales apply to track scales. They should be kept free from trash, 
and if not under cover must be kept free from snow and ice. They 
