Some Additional Reference Information:Less trucks, couplers, handrails, and piping, Concept Models offers HO-Scale resin kits of the one-off GATX 96500 and UTLX 83699 "Whale-Belly" Super Tankers.

https://www.con-sys.com/product_GATX96500.htmhttps://www.con-sys.com/pdf/GATX60000_GAL_INSTR.pdfQuality Craft Models also produced (i.e., as its Stock Number G-1 GATX 96' 60,000 GAL. TANK CAR) a vintage HO-Scale basswood and pewter craftsman kit of GATX 96500.
Quality Craft Models G-1 Kit
Unpainted Quality Craft Models G-1 Kit Build-Up
Unpainted Quality Craft Models G-1 Kit Build-Up
Unpainted Quality Craft Models G-1 Kit Build-UpAccording to a ten year old Model Railroader forum board post by Tom McInerney, three view diagrams with dimensions of GATX 96500 can be found in the second edition copy of the GATX Tank Car Manual, copyright General American Transportation Corporation, 1966. Library of Congress no. 66-21208.
Pages 129 and 170 must be referenced for the details on the side fills and drains.
About the prototype:Donated to the National Museum of Transportation in St. Louis, Missouri by the General American Transportation Company in 1971, built in September 1965 to transport Anhydrous Ammonia or Liquefied Petroleum Gas, an experimental car that never entered interchange service, the prototype 60,018 Gallon GATX 96500 "Whale-Belly" Super Tanker is 96' 7 5/8" long, has an empty weight of 193,300 pounds, and a fully loaded weight of 440,000 pounds.


GATX 96500 was the second jumbo tanker to be constructed in the United States.
http://www.railgoat.railfan.net/railwhales/bynumber/gatx096500.htmWith a 50,105 gallon capacity, an empty weight of 176,700 pounds, and a fully loaded weight of 440,000 pounds, the first of these behemoths was the UTLX 83699, which was constructed by the Union Tank Car Company in March 1963.
One of only three of the super tankers that were preserved after decommissioning, UTLX 83699 was scrapped after it was seriously damaged by Hurricane IKE in 2008.
http://www.railgoat.railfan.net/railwhales/bynumber/utlx083699.htmFederal regulation 35 CFR 14216 which was proposed on December 11, 1969 and took effect on December 1, 1970 prohibited the construction of jumbo tank cars with capacities greater than 34,500 gallons, or with maximum gross rail loaded weights exceeding 263,000 pounds.
Notwithstanding the creation of federal regulation 35 CFR 14216, the future of any remaining Super Tankers was doomed by the Association of American Railroads' establishment of a service life of forty-years (which had previously been set at fifty-years) for interchange service freight cars that were constructed prior to July 1, 1974.
http://www.railgoat.railfan.net/railwhales/index.htmhttp://www.railgoat.railfan.net/railwhales/a-roster.htm?http://www.railgoat.railfan.net/railwhales/a-1963-1970.htm?http://www.railgoat.railfan.net/railwhales/a-1971-2013.htm?