Shall be in writing;

Shall stipulate that the arbitration is had under the provisions of this chapter;

Shall state whether the board of arbitration is to consist of three or of six members;

Shall be signed by the duly accredited representatives of the carrier or carriers and the employees, parties respectively to the agreement to arbitrate, and shall be acknowledged by said parties before a notary public, the clerk of a district court or court of appeals of the United States, or before a member of the Mediation Board, and, when so acknowledged, shall be filed in the office of the Mediation Board;

Shall state specifically the questions to be submitted to the said board for decision; and that, in its award or awards, the said board shall confine itself strictly to decisions as to the questions so specifically submitted to it;

Shall provide that the questions, or any one or more of them, submitted by the parties to the board of arbitration may be withdrawn from arbitration on notice to that effect signed by the duly accredited representatives of all the parties and served on the board of arbitration;

Shall stipulate that the signatures of a majority of said board of arbitration affixed to their award shall be competent to constitute a valid and binding award;

Shall fix a period from the date of the appointment of the arbitrator or arbitrators necessary to complete the board (as provided for in the agreement) within which the said board shall commence its hearings;

Shall fix a period from the beginning of the hearings within which the said board shall make and file its award: Provided, That the parties may agree at any time upon an extension of this period;

Shall provide for the date from which the award shall become effective and shall fix the period during which the award shall continue in force;

Shall provide that the award of the board of arbitration and the evidence of the proceedings before the board relating thereto, when certified under the hands of at least a majority of the arbitrators, shall be filed in the clerk’s office of the district court of the United States for the district wherein the controversy arose or the arbitration was entered into, which district shall be designated in the agreement; and, when so filed, such award and proceedings shall constitute the full and complete record of the arbitration;

Shall provide that the award, when so filed, shall be final and conclusive upon the parties as to the facts determined by said award and as to the merits of the controversy decided;

Shall provide that any difference arising as to the meaning, or the application of the provisions, of an award made by a board of arbitration shall be referred back for a ruling to the same board, or, by agreement, to a subcommittee of such board; and that such ruling, when acknowledged in the same manner, and filed in the same district court clerk’s office, as the original award, shall be a part of and shall have the same force and effect as such original award; and

Shall provide that the respective parties to the award will each faithfully execute the same.

The said agreement to arbitrate, when properly signed and acknowledged as herein provided, shall not be revoked by a party to such agreement: Provided, however, That such agreement to arbitrate may at any time be revoked and canceled by the written agreement of both parties, signed by their duly accredited representatives, and (if no board of arbitration has yet been constituted under the agreement) delivered to the Mediation Board or any member thereof; or, if the board of arbitration has been constituted as provided by this chapter, delivered to such board of arbitration.