John B. LaRocco, Referee


              (Brotherhood of Maintenance of Way Employes


PARTIES TO DISPUTE:
              (Burlington Northern Railroad Company


STATEMENT OF CLAIM: "Claim of the System Committee of the Brotherhood that:

 1. Mr. J. E. Cooksey shall be afforded a seniority date as foreman as of May 26, 1982 in conformance with Rule 2(b)(1) [System File B-1343/MWC 83-1-14A)."

              OPINION OF BOARD: The issue in this case centers on the proper interpretation and application of Rule 2(b)(1) which reads:


          "An employe shall establish seniority in other than Class 1 retroactively as of the date assigned a position or vacancy in such class after the employe has performed service on 20 working days in such class without being disqualified."


The relevant facts are undisputed. Claimant acquired a June 30, 1975, seniority date as a monthly rated Machine operator which, like Foreman and Assistant Foreman, is a Class 4 position. By Bulletin ED-108A, the Carrier awarded Claimant an A 16, 1982. After claimant performed service on eleven work days, the Carrier abolished the Sled Gang. Next, Claimant was assigned to fill a temporary vacancy on a monthly rated Machine Operator position at Springfield, Missouri. Claimant protected the position for seven work days between July 1, 1982 and July 12, 1982. On July 13 and 14, 1982, Claimant worked as an Assistant Foreman on a Surfacing Gang. Machine Operator position and the Carrier permanently awarded Claimant the position on October 8, 1982.

 The Organization urges this Board to order the Carrier to grant Claimant seniority as a Foreman Carrier awarded him the Assistant Foreman job on the Sled Gang. The organization argues that Claiman Because Claimant worked eleven days as an Assistant Foreman, seven days as a Machine Operator and two additional days as an Assistant Foreman, the Organization concludes that Cl 2(b)(1). On the other hand, the Carrier contends that Rule 2(b)(1) has always been interpreted to require worker to occupy a single position in Class 4 for twenty days. If he meets the condition, the Carrier asserts that the worker achieves seniority to the particular positions in Class 4.
                      Award Number 26283 Page 2

                      Docket Number MW-25636


On its face, Rule 2(b)(1) is ambiguous. The Rule is susceptible to more than one interpretation. Thus, this Board must inquire into the parties' past practice of applying the Rule. If the Organization's interpretation were correct, Claimant would have acquired seniority to all Class 4 positions when he gained his monthly rated Machine operator seniority back in 1975. His Machine Operator work was never counted towards obtaining seniority as a Foreman. The past practice, for twenty days. Therefore, Claimant did not satisfy the requirements of Rule 2(b)(1).

 FINDINGS: The Third Division of the Adjustment Board, after giving the
 parties to this dispute due notice of hearing thereon, and upon the
 whole record and all the evidence, finds and holds:

 That the Carrier and the Employes involved in this dispute are respectively Carrier and Employes within the meaning of the Railway Labor Act, as approved June 21, 1934;

 That this Division of the Adjustment Board has jurisdiction over the dispute involved herein; and

        That the Agreement was not violated.


                        A W A R D


        Claim denied.


                            NATIONAL RAILROAD ADJUSTMENT BOARD

                            By Order of Third Division


Attest: ,

        Nancy J. ever - Executive Secretary


Dated at Chicago, Illinois, this 24th day of April 1987.