49 CFR 238.709 – Fluid entry inhibition
(a) The skin covering the forward-facing end of a Tier III trainset shall be—
(1) Equivalent to a
(2) Designed to inhibit the entry of fluids into the cab; and
(3) Affixed to the collision posts or other main structural members of the forward end structure so as to add to the strength of the end structure.
(b) Information used to demonstrate compliance with the requirements of this section shall at a minimum include a list and drawings of the structural elements considered in satisfying the thickness-strength requirement of this section, and calculations showing that the thickness-strength requirement is satisfied.