49 C.F.R. § A to Part 179
1. This test procedure is designed to verify the integrity of new or untried tank-head puncture-resistance systems and to test for system survivability after coupler-to-tank-head impacts at relative speeds of 29 km/hour (18 mph). Tank-head puncture-resistance is a function of one or more of the following: Head thickness, jacket thickness, insulation thickness, and material of construction.
2. Tank-head puncture-resistance test. A tank-head puncture-resistance system must be tested under the following conditions:
a. The ram car used must weigh at least 119,295 kg (263,000 pounds), be equipped with a coupler, and duplicate the condition of a conventional draft sill including the draft yoke and draft gear. The coupler must protrude from the end of the ram car so that it is the leading location of perpendicular contact with the impacted test car.
b. The impacted test car must be loaded with water at six percent outage with internal pressure of at least 6.9 Bar (100 psig) and coupled to one or more "backup" cars which have a total weight of 217,724 kg (480,000 pounds) with hand brakes applied on the last "backup" car.
c. At least two separate tests must be conducted with the coupler on the vertical centerline of the ram car. One test must be conducted with the coupler at a height of 53.3 cm (21 inches), plus-or-minus 2.5 cm (1 inch), above the top of the sill; the other test must be conducted with the coupler height at 79 cm (31 inches), plus-or-minus 2.5 cm (1 inch), above the top of the sill. If the combined thickness of the tank head and any additional shielding material is less than the combined thickness on the vertical centerline of the car, a third test must be conducted with the coupler positioned so as to strike the thinnest point of the tank head.
3. One of the following test conditions must be applied:
| Minimum weight of attached ram cars in kg (pounds) | Minimum velocity of impact in km/hour (mph) | Restrictions |
| 119,295 (263,000) | 29 (18) | One ram car only. |
| 155,582 (343,000) | 25.5 (16) | One ram car or one car plus one rigidly attached car. |
| 311,164 (686,000) | 22.5 (14) | One ram car plus one or more rigidly attached cars. |
4. A test is successful if there is no visible leak from the standing tank car for at least one hour after impact.
49 C.F.R. §A to Part 179