Form 1 NATIONAL RAILROAD ADJUSTMENT BOARD Award No. 8823
 SECOND DIVISION Docket No. 8424-'t
 2-C&NW-SM-'81
 The Second Division consisted of the regular members and in
 addition Referee John B. IaRocco when award was rendered.
 ( Sheet Metal Workers' International Association
 Parties to Dispute:
 ( Chicago and North Western Transportation Company

 Dispute: Claim of Employes:
I. That the Carrier under the current agreement, assigned other than employes
 of the sheet Metal Workers' Craft (by the assignment of Carmen Helpers and
 Coach Cleaners) to perform work covered by Rules 29, 53 and 103, This; work
 assignment consisted of the removing and replacing of drain pans, overhead
 doors and the blowing of condensers on certain coaches as enumerated in
 Employes' Exhibits 1 through 5 on the dates of April 11, 12, 13, 14 and
 17, 1978.
 2. That accordingly,the Carrier be ordered to additionally compensate Sheet
 Metal Workers, A. Droho, 3. Osborne and M. Chalus for eight (8) hours
 each at the straight time rate for the date of April 11, 1978. For the
 date of April 12, 1978, Sheet Metal Workers, J. Nurnburg, T. Land, W.
 Rosso and S. Scolastica in the amoung of eight hours each at the straight
 time rate. For the date of April 13, 1978, Sheet Metal Workers, R.
 Bauman, A. Mahilum, N. Christopherson and A. Droho in the amount of
 eight hours each at the straight time rate. For the date of April 14_
 1978, Sheet Metal Workers, J. Land, W. Rasso, S. Scolastica, M. Chalus
 and S. Osborne in the amount of eight hours each at the straight time
 rate. For the date of April 17, 1978, Sheet Metal Workers, J. Nurnburg,
 R. Bauman, A. Mahilum and N. Shristopherson in the amount of eight hours
 each at the straight time rate.
 Findings
The Second Division of the Adjustment Board, upon the whole record and all the evidence, finds that:

 The carrier or carriers and the employe or employes involved in this dispute are respectively carrier and employe within the meaning of the Railway Labor Act: as approved June 21, 193+.

 This Division of the Adjustment Board has jurisdiction over the dispute involved herein.

The organization has brought this claim on behalf of nine sheet metal workers alleging the carrier improperly assigned work (which the organization says is reserved exclusively to sheet metal workers) to other crafts on April 11, 12, 1?., 14 and 17, 1978. The claimants seek a total of approximately 152 hours of pay apt the pro rata rate.
 Form 1 Award No. $823
 Page 2 Docket No. 842-T
 2-C&NW-SM-'81

 Each spring, the carrier prepares the air conditioning equipment on its commuter passenger coaches for summer use. The air conditioning preparation project consists of many different tasks (repair, cleaning & maintenance) including the blowing of condensers. The carrier has engaged in the air conditioning preparation project each spring since the late I950's when the air conditioned coaches were placed into service on the carrier's suburban Chicago lines. On the dates in question, some sheet metal workers participated in the air conditioning renewal process but they were assisted by coach cleaners and carmen.
conditioning equipment for summer use (including blowing the condensers) is within
 the exclusive province of sheet metal workers under Rules 103, 29 and 53. Rule
 103 classifies the type of ks which constitute sheet metal work. The other
 rules provide that sheet metal workers shall perform sheet metal work with certain
 exceptions. The carrier refutes the organization's contention that all the disputed
 work is covered by the sheet metal worker classification rule. While the carrier
 acknowledges that a portion of the air conditioning preparation proj*at is reserved
 exclusively to sheet metal workers, it contends that the claimants did perform that
 portion of the work. According to the carrier, coach cleaners and c armen have,
 since the late 1950'x, assisted sheet metal workers in the spring air conditioning
 project. Moreover, the carrier alleges that a former general chairman of the sheet
 metal workers in 1977 orally agreed that carmen and coach cleaners could continue
 to perform the disputed work in accord with the past practice. In its third party _
 submission, the carmen assert that its classification rule permits carmen to perform Iwo
 a3r~ emnditionitag maintenance work on passenger cars. Even if the carmen classification
 rule is not broadly construed to cover such work, the carmen contend that historically,
 on this property, the csrmen have performed the work claimed to be exclusively
 reserved to the sheet metal workers.

 We initially note that the carrier also argues that the incidental work rule applies to this claim. However, we cannot pass on the applicability of the incidental work rule because the carrier raised this argument for the first time before this Board. Numerous past decisions of this Board confine our consideration to arguments which were properly raised while the case was being handled on the property.

 After carefully considering the arguments of all the interested parties and the facts in the record, we rule that the disputed air conditioning work has historically and traditionally been performed by a combination of crafts on this property. A practice has developed which permits the carrier to assign part of the work to carmen and coach cleaners to assist the sheet metal workers in preparing the air conditioning for summer use. The organization has not presented a preponderance of evidence to demonstrate that the project is within the exclusive jurisdiction of sheet metal workers. Over a period of years, the practice arose which gives several crafts overlapping jurisdiction to perform portions of air conditioning preparation work. Thus, we must deny the claim.

 We emphasize that our decision applies only to the practice which has developed on this property. Also, sheet metal workers continue to have a right to perform the portion of the air conditioning preparation work that they have traditionally
 performed each spring. `1~
 Form 1 Award No. 8823
 Page 3 Doclaet No. 8424-·T
 2-c&Nw-sri-' 81




                            By Order of Second Division


Attest: Executive Secretary
 National Railroad Adjustment Board

              ~.-_


BY
        v - _


      s y rie Brasch - Administrative Assistant


Dated a Chicago, Illinois, this 18th day of November, 1981.