49 CFR § 1104.13 - Replies and motions.
(a)Time. A party may file a reply or motion addressed to any pleading within 20 days after the pleading is filed with the Board, unless otherwise provided.
(b)Number of copies. The original of a reply or motion should be accompanied by the same number of copies required to be filed with the pleading to which the reply or motion is addressed.
(c)Reply to a Reply. A reply to a reply is not permitted.