12-17-2010, 08:54 PM
Gary S Wrote:Now, on the "access doors", why would a scale test car need them? Wouoldn't the thing just be a huge hunk of metal?
Gary, I think that scale test cars had a number of larger, fixed weights, and also some smaller removeable ones - there's some info on the original scale test cars HERE (scroll down to Page 116 for the stuff pertaining to railroads, plus a photo).
The car's weight could change over time due to brake wear, repairs, etc. and they were required to be periodically re-weighed on a calibrated scale to ensure that their weight was as-stated on the dimensional data - otherwise, they'd be useless for calibrating other scales. According to the info in the link, a scale was required to be accurate to within 200lbs. when measuring a weight of 50 tons. The access doors would allow these smaller weights to be added or removed to/from the test car, keeping its weight accurate.
Wayne