Observations

The Petroleum Handbook (Royal Dutch/Shell Group, 1959) points out that it costs less to deliver products with large vehicles than with small ones, thus the size of the tanks in a tank truck or trailer increases with manufacture, limited by physics and highway regulations and other legislation in the various states. In 1959 a capacity of 7200 U.S. gallons was considered a large volume tank for a truck or trailer. This, of course, has been exceeded in the ensuing years (see photo of Citgo-Country Fair tank trailer).

The Petroleum Shell Handbook (1959) also remarked on loads such as bitumen and sulphur (hot liquids) which are carried by truck in specially insulated tanks which also have heating coils. This is the same situation attended to by railway tank cars.

Tank trucks are top-heavy and can easily turn over. The trained driver is a highly skilled individual and knows how to contend with surges of the liquid load. A loaded tank truck and trailer can roll over at posted speeds on some curves, so the driver slows down for a number of road conditions and avoids quick stops and starts.

Some liquid tanks are divided into smaller tanks (compartments) by bulkheads for distinct liquids. Some tanks have baffles which are bulkheads with holes that permit the liquid to flow through. Baffles help to regulate the forward-backward surges, but side-to-side surges can still occur and may cause a tip-over. A smooth bore tank is dangerous when starting or stopping because the full load pushes strongly in one direction then the other and can propel the vehicle (Commonwealth of Pennsylvania, Commercial Driver’s Manual, 2001).

In 1959 the Oil & Gas Journal published a huge magazine volume commemorating 100 years of petroleum progress ( a centennial issue of the oil industry). It consisted of 652 pages including the ads (it was chock full of them). Just about everything was covered, including transportation which at that time was the moving of 17 million barrels of oil and 32 billion cubic feet of gas. But when it came to tank trucks, only two short paragraphs were written and two small vintage photographs accompanied them. The short text stated that tank trucks handled 35% of the refined products’ traffic at that time (that’s a lot!). Leafing through all the pages, it was found that only two advertisements showing a tank truck were in the whole volume! One was a portion of a display ad by U.S. Steel showing a Petgas tank truck made of steel and carrying LPG. The other was a small photograph of a Sunray DX tank truck. Neither held significant portions of the ads. Tank truck ads were plentiful in the 1920’s and now-a-days. What happened in 1959?