As used in this part—

Base-year employer means the railroad employer(s) for whom a claimant worked and earned compensation creditable under the Railroad Unemployment Insurance Act during the base year. The base year is the calendar year immediately preceding the benefit year for which a claim is being filed. A benefit year is generally the period July 1 through the following June 30.

Party means the claimant, the base-year employer(s), or any person so designated under this part.