"Note that Kaminski states on pg 241 that "By the late 1940's, the early wood
running boards and side platforms were being replaced in new car
construction with steel grid types."
All newly built tank cars were required to have metal running boards applied and platforms, if applied, as of January 1, 1948. The ICC granted exceptions to that ruling for tank cars carrying any commodity which may have had corrosive effects on metal, thus wood platforms were permissible for certain applications of platforms, but not running boards.
Metal running boards and platforms were subject to approval by the AAR as: Group 1) for use as metal running boards for box and other roofed cars (including type "LO" covered hopper cars), and for metal brake steps for all cars, also for dome steps and platforms on tank cars when the length of unsupported span does not exceed 4' 0"; Group 2) For use as metal running boards for box and other roofed cars (including type "LO" covered hopper cars), and for dome steps and dome platforms on tank cars when the length of unsupported span is over 4' 0", but not more than 7' 0"; Group 3) For use as metal running boards for tank cars when the length of unsupported span is over 7' 0", but less than 10' 0".
Specifications: 2) The running boards, brake steps, and foot boards shall be of material and structure which will provide the same or a greater degree of strength and safety as that of wood. 3) Running boards, foot boards, and brake steps shall have uniform anti-skid tread surfaces and be of a construction to provide at least 50 per cent clear opening that will permit elimination of accumulation of snow and ice. Openings in tread surfaces shall not exceed 1-1/2" in at least one direction and not more than 6" in the other direction.
A static test load of 200 pounds applied at the center of the span across the full width of the section shall not create a deflection of greater than 1/8" for 4' section, 1/4" for 7' section and 1/4" for 10' section.
The thickness of running boards suitable for and applied to tank cars ranged from 1-1/2" to 2-1/4" in order to meet the requirements of the AAR's static test.
Tank cars built prior to January 1, 1948 were not required to have wood running boards and/or platforms replaced unless they were rebuilt under the provisions of AAR Interchange Rule 112. If a new tank was applied to an existing underframe, or a new underframe was placed under an existing tank the car was required to be fitted with metal running boards and metal platform applied.