49 C.F.R. § 511.24 – Interlocutory appeals.

(a) General. Rulings of the Presiding Officer may not be appealed to the Administrator prior to the Initial Decision, except as provided herein.
(b) Exceptions—(1) Interlocutory appeals to Administrator. The Administrator may, in his or her discretion, entertain interlocutory appeals where a ruling of the Presiding Officer:
1. (i) Requires the production or disclosure of records claimed to be confidential;
2. (ii) Requires the testimony of a supervisory official of the agency other than one especially cognizant of the facts of the matter in adjudication;
3. (iii) Excludes an attorney from participation in a proceeding pursuant to § 511.42(b).
4. (2) Procedures for interlocutory appeals. Within ten (10) days of issuance of a ruling, any party may petition the Administrator to entertain an interlocutory appeal on a ruling in the categories enumerated above. The petition shall not exceed fifteen (15) pages. Any other party may file a response to the petition within ten (10) days of its service. The response shall not exceed fifteen (15) pages. The Administrator shall thereupon act upon the petition, or the Administrator shall request such further briefing or oral presentation as he may deem necessary.
5. (3) Interlocutory appeals from all other rulings—(i) Grounds. Interlocutory appeals from all other rulings by the Presiding Officer may proceed only upon motion to the Presiding Officer and a determination by the Presiding Officer in writing, with justification in support thereof, that the ruling involves a controlling question of law or policy as to which there is substantial ground for differences of opinion and that an immediate appeal from the ruling may materially advance the ultimate termination of the litigation, or that subsequent review will be an inadequate remedy.
6. (ii) Form. If the Presiding Officer determines, in accordance with paragraph (b)(3)(i) of this section that an interlocutory appeal may proceed, a petition for interlocutory appeal may be filed with and acted upon by the Administrator in accordance with paragraph (b)(2) of this section.
(c) Proceedings not stayed. A petition for interlocutory appeal under this part shall not stay the proceedings before the Presiding Officer unless the Presiding Officer shall so order, except that a ruling of the Presiding Officer requiring the production of records claimed to be confidential shall be automatically stayed for a period of (10) days following the issuance of such ruling to allow an affected party the opportunity to file a petition for an interlocutory appeal pursuant to § 511.24(b)(2). The filing of such a petition shall automatically extend the stay of such a ruling pending the Administrator's action on such petition.