238.409—Forward end structures of power car cabs.
This section contains requirements for the forward end structure of the cab of a power car. (A conceptual implementation of this end structure is provided in Figure 1 to this subpart.)
(a) Center collision post.
The forward end structure shall have a full-height center collision post, or its structural equivalent, capable of withstanding the following:
(1)
A shear load of 500,000 pounds at its joint with the underframe without exceeding the ultimate strength of the joint;
(2)
A shear load of 150,000 pounds at its joint with the roof without exceeding the ultimate strength of the joint; and
(3)
A horizontal, longitudinal force of 300,000 pounds, applied at a point on level with the bottom of the windshield, without exceeding its ultimate strength.
(b) Side collision posts.
The forward end structure shall have two side collision posts, or their structural equivalent, located at approximately the one-third points laterally, each capable of withstanding the following:
(1)
A shear load of 500,000 pounds at its joint with the underframe without exceeding the ultimate strength of the joint; and
(2)
A horizontal, longitudinal force of 300,000 pounds, applied at a point on level with the bottom of the windshield, without exceeding its ultimate strength.
(c) Corner posts.
The forward end structure shall have two full-height corner posts, or their structural equivalent, each capable of withstanding the following:
(1)
A horizontal, longitudinal or lateral shear load of 300,000 pounds at its joint with the underframe, without exceeding the ultimate strength of the joint;
(2)
A horizontal, lateral force of 100,000 pounds applied at a point 30 inches up from the underframe attachment, without exceeding the yield or the critical buckling stress; and
(3)
A horizontal, longitudinal or lateral shear load of 80,000 pounds at its joint with the roof, without exceeding the ultimate strength of the joint.
(1)
Equivalent to a 1/2 -inch steel plate with a 25,000 pounds-per-square-inch yield strength—material of a higher yield strength may be used to decrease the required thickness of the material provided at least an equivalent level of strength is maintained;
(3)
Sealed to prevent the entry of fluids into the occupied cab area of the equipment. As used in paragraph (d), the term “skin” does not include forward-facing windows and doors.