Disability of the Trial Court judge

If by reason of death, sickness, resignation, removal, retirement, or other disability, the judge or judges whose decision has been appealed is unable to perform the duties to be performed under these rules by the court in which the action was heard, then any other judge sitting in or assigned to such court may, on assignment by the Chief Justice of the District Court, or of the Municipal Court of the City of Boston, as the case may be, perform those duties.