Opinion by
The Pennsylvania Labor Relations Board (Board) and the New Castle Area Transit Authority (Authority)1 appeal a Lawrence County Common Pleas Court order holding that a dispatcher/secretary should be included in the bargaining unit of Amalgamated Transit Union, Local 898 (Union). We reverse.
On April 6, 1982, the Union sought to include the position, dispatcher/secretary, into an existing twenty-two member barg-aining unit composed of drivers, me*146ehauics and 'bus washers employed by the Authority.2 The dispatcher/secretary position iwas held by Rosalie Costa. After a hearing, the examiner held that Costa should be excluded from the unit. The Board, affirmed and held that Costa lacked a community of interest with the preexisting unit of blue collar employees. The Board found that Costa’s duties were primarily secretarial/clerical. The common pleas court reversed and held that the Board erred as a matter of law by relying on the effects of community of interest rather than over-fragmentization.
The Board and the Authority contend that the common pleas court erred as a matter of law in considering over-fragmentization since Costa and the existing' Union members did not share a community of interest. We agree.
Section 604(1) of the Pennsylvania Labor Relations Act3 (PLRA) provides:
The board shall determine the appropriateness of a unit which shall be the public employer unit or a subdivision thereof. In determining the appropriateness of the unit, the board shall:
(1.) Take into consideration but shall not be limited to the following:
(i) public employes must have an identifiable community of interest, and
(ii) the effects of over-fragmentization. (Emphasis added.)
*147In reviewing the Board’s application of Section 604 of PLEA, this Court must rely upon the expertise of the Board in this specialized field to weigh and determine the facts. The School District, Township of Millcreek v. Millcreek Education Association, 64 Pa. Commonwealth Ct. 389, 391-2, 440 A.2d 673, 674 (1982). This Court’s scope of review is limited to a determination of whether the Board’s findings are supported by substantial evidence and whether the conclusions are reasonable, and not arbitrary, capricious or illegal. Id.
Our review of the record reveals substantial evidence to support the Board’s finding of a lack of community of interest between Costa and the preexisting unit. The evidence discloses that Costa’s primary duties were those of a bookkeeper and secretary.4 In this “white collar” position, she in effect acted as a liaison between the drivers and the management.
The Union contends that Section 604 mandates consideration of both the community of interest and the over-fragmentization effects. We disagree.
If the Board’s finding that the proposed new members lack an identifiable community of interest with the existing membership is supported by substantial evidence, then any contention regarding over-fragmentization is without foundation. Association of Pennsylvania State College and University Faculties *148v. Pennsylvania Labor Relations Board, 34 Pa. Commonwealth Ct. 239, 383 A.2d 243 (1978).
' We hold that the common pleas court erred as a matter of law in concluding that a dispatcher/seeretary should be included in the Union’s bargaining unit.5
Reversed.
Order
The Lawrence County Common Pleas Court order, No. 90 of 1983 dated January 11, 1984, is reversed.