(Brotherhood of Railroad Signalmen PARTIES TO DISPUTE:

STATEMENT OF CLAIM: Claim of the General Committee of the Brotherhood of
 Railroad Signalmen on the Southern Pacific Transportation Company (Pacific Lines):

 (a) That the Southern Pacific Transportation Company has violated and continues to violate the Memorandum of Agreement between the Southern Pacific Company (Pacific Lines) and the Employes of the Signal Department represented by the Brotherhood of Railroad Signalmen, SIG 116-56, dated November 30, 1960, and particularly Paragraph 10 of the Memorandum which specifically provides that Air Conditioning among other facilities shall be provided at the Sacramento Signal Shop.

 (b) We request that the Wiring and Blacksmith Shop sections of
 Sacramento Signal Shop be promptly provided with Air Conditioning as speci
 fied in Memorandum of Agreement in lieu of the _Swamp Coolers and portable
 fans now provided. /Carrier's File: Sig 60-39/

 OPINION OF BOARD: In June 1961 Carrier established a System Signal Shop
 at Sacramento. This shop occupies two buildings accomo
 dating four different work activities: a machine shop, relay shop, wiring
 shop and blacksmith shop. We are concerned herein with the building occupied
 by the wiring shop and the blacksmith shop. In contemplation of the estab
 lishment of the System Signal Shop, the parties entered into a Memorandum
 of Agreement effective November 30, 1960 which provided among other items
 in Section 10:

Petitioner contends that the; evaporative air cooling system with auxiliary fans installed by Carrier in 1961 is neither air conditioning nor adequate as provided in the Agreement of November 1960. Petitioner presented no evidence whatever on the property in support of its position, although some data concerning temperatures inside the facility, which must be disregarded, was submitted duri agree with Petitioner's contention with respect to the system, since we hold that "air conditioning" is a generic term which applies to both evaporative and refrigerative systems.


Most importantly, disregarding Carrier's speculative assertion with respect to the Organization's motivation in bringing this claim, we recognize the interest of both parties in their being satisfactory working conditions for the employes affected. Since the record discloses no probative evidence with respect there were no complaints for almost ten years, we can find no support for the Organization's position. We have held in many Awards over the years that when there is any doubt as to the intent of the parties or the meaning of an ambiguous contract provision, the conduct of the parties over a period of time is the best evidence of their intent (Awards 14240 and 14936 for example). Although we canno above, we are certain that the essential mutuality of interest of both parties in resolving the issu
        FINDINGS: The Third Division of the Adjustment Board, upon the whole record and all the evidence, finds and holds:


        That the parties waived oral hearing;


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: W

        Executive Secretary


Dated at Chicago, Illinois, this 28th day of September 1973.