The strength of the tank car begins with the integrity of the tank.

The main, load-bearing structure of a modern DOT 117A100W tank car is the tank shell. It is constructed of 9/16” thick, TC-128 Grade B steel. The plates are normalized to refine the steel’s grain and produce a tough, more ductile material.

After normalization, the plates are rolled to form rings and fitted to the tank’s pressed, 2:1 ellipsoidal heads. The tank rings and heads are welded together using an automated, full-penetration, submerged arc process. The mating edges of the two innermost rings are precisely cut to give the tank a ¼” per foot slope to the middle for Union Tank Car’s celebrated Funnel Flow®.

The unified vessel contains the product and also provides the backbone to which the operational fittings nozzles, running gear, and safety appliances are attached.


  • 1 Tank Shell
  • 2 Tank Head
  • 3 Full Penetration Weld