49 CFR §238.703

1. (a)General. To demonstrate resistance to loss of occupied volume, Tier III trainsets shall comply with both the quasi-static compression load requirements in paragraph (b) of this section and the dynamic collision requirements in § 238.705.
2. (b)Quasi-static compression load requirements.
   1. (1)Each individual vehicle in a Tier III trainset shall resist a minimum quasi-static end load applied on the collision load path of:
      1. (i)800,000 pounds without permanent deformation of the occupied volume; or
      2. (ii)1,000,000 pounds without exceeding either of the following two conditions:
         1. (A)Local plastic strains no greater than 5 percent; and
         2. (B)Vehicle shortening no greater than 1 percent over any 15-foot length of the occupied volume; or
      3. (iii)1,200,000 pounds without crippling the body structure. Crippling of the body structure is defined as reaching the maximum point on the load-versus-displacement characteristic.
   2. (2)To demonstrate compliance with this section, each type of vehicle shall be subjected to an end compression load (buff) test with an end load magnitude no less than 337,000 lbf (1500 kN).
   3. (3)Compliance with the requirements of paragraph (b) of this section shall be documented and submitted to FRA for review and approval.