Excerpt from the report Summary: This report is based on a series of studies to determine the most efficient method of protecting freshly killed beef of canner and cutter grade in transit. Twelve motortruck trailers, equipped with various types of mechanical refrigerating units, were tested to compare different methods of circulating the cold air from the refrigerating units around and through the load. Comparisons also were made of meat-hanging rails of two designs, (1) heavy wood crossbeams and (2) lightweight metal rails extending the length of the trailer body.