The Timeline for 1967 says the AAR ended mandatory periodic reweighing of freight cars. Was this just for certain types, or is the date wrong?
From the "Field Manual of the A.A.R. interchange Rules", 1977 edition:
Rule 70, Section 2 Subsequent Lightweighing
a. All freight cars, except as otherwise provided in Section 2.c, must be re-lightweighed and re-stenciled after the expiration of 60 months.
b. (Paraphrase: if the lightweight is missing or illegible it must be reweighed immediately)
c. Tank cars, covered hopper cars, flat cars with multi-deck racks, or special superstructures, mechanical refrigerator cars, and house type ras with special lading protective devices must be re-weighed and re-stenciled only by owners or their authorized representatives.
(1) When car bears no lightweight stenciling.
(2) When repairs or alterations result in a change of weight in excess of the permissible light weight tolerances shown in Section 2.d.
