"During treating run No. 13, which was made in May, 1951, light gas oil (395 to 658 F. boiling range) produced by coking crude N-T-U shale oil was acid treated and inhibited to produce Diesel fuel for an extended test by the Denver Rio Grande Western Railroad in a switching locomotive. Additional fuel for use in Diesel equipment at the Rifle station also was produced in the run. The light gas oil was treated in three steps ,consisting of (1) tar-acid and tar-base removal, (2) acid treatment with 16.3 pounds of 66 Be'sulfuric acid per barrel of raw oil charged, and (3) an additional acid treatment using 3.2 pounds of sulfuric acid per barrel of raw oil. The oil thus treated ,was inhibited with 0.05 volume percent of National Aluminate Corporation X-159 inhibitor. An over-all product yield of 72.7 volume percent was obtained. The Denver & Rio Grande Railroad used 4,643 gallons of the shale-oil Diesel fuel in a switch engine for a test operation of 751 hours duration. The fuel was found to be satisfactory in all respects. Further, no difficulty of any kind was encountered when this fuel was used in equipment at the Rifle Station."