PARTIES Brotherhood of Maintenance of Way Employes
 DISPUTE: and -
 ' The Baltimore and Ohio Railroad Company
 STATEMENT On various dates between May 10 and June 1, 1978,
 TF
 CL7IM: Carrier violated the Schedule Agreement when it
 used Boilermaker Clyde Poling to perform the work
 of cutting holes and welding brackets so a safety
 chain could be installed on all platforms in the
 roundhouse in Cumberland, Maryland. Claimant, Car
 penter R. G. Kerns, should be paid 20 hours at car
 penter's rate because of that violation.
 FINDINGS: To prevail, Petitioner must prove by-competent
 evidence, as distinguished from mere assertion, that
 the disputed work -- cutting holes and welding brack-_
 ets to platforms in the roundhouse in order that
 safety chains could be installed -- belongs exclusively
 to Bridge and Building forces and cannot validly be
 performed by boilermakers.
 Petitioner has not submitted sufficient evidence
 PLB No. 2778 2
 Award No. 37
 Case No. 77
 to sustain that burden of proof. The work in question does not
 affect the structural integrity of the roundhouse and has not been -
 reserved exclusively for maintenance of way employes by any agree
 ment or, so far as the record shows, established continuous practice.
 The evidence to which we have been referred is not sufficient to es
 tablish such a practice.
 It was not a breach of the applicable agreement for boilermaker to devote 20 hours to cutting holes in, and welding brackets to, the platforms in the roundhouse.
 In reaching our decision, we had considered with care the submissions and oral arguments of each party, including the Boilermakers who were duly permitted to appear as an intervenor. -

 AWARD: Claim denied.