RP 3000 provides guidance on the material characterization, transport classification, and quantity measurement for overfill prevention of petroleum crude oil for the loading of rail tank cars. This document applies only to petroleum crude oil classified as Hazard Class 3-Flammable Liquid under the U.S. Code of Federal Regulations (CFR) at the time of publication. RP 3000 identifies criteria for determining the frequency of sampling and testing of petroleum crude oil for transport classification. It discusses how to establish a sampling and testing program, and provides an example of such a program. This document provides guidance on Packing Group (PG) assignment, including the potential effect of heel, and mixing of crude oils of differing PGs. The document provides guidance on initial testing and an ongoing sampling and testing for assignment of PG. RP 3000 provides guidance on determining the loading target quantity (LTQ) of crude oil transported by rail tank car. This includes crude oil temperature and density determination, identification of sampling points based on loading scenarios, and measurement equipment and processes. Guidance on the documentation of measurement results and record retention is also provided.