Connections between members of the car frames and platform shall be riveted, bolted, or welded and shall meet the following specifications:

(1) Where used through sloping flanges of structural members bolt heads shall be of the tipped head type or shall be fitted with beveled washers.

(2) Nuts used on sloping flanges of structure members shall seat on beveled washers.

(3) Welding of parts upon which safe operation depends shall be done in accordance with the appropriate standards established by the American Welding Society.