Part timers are screwed, but package drivers get the supplemental Holiday rate, which is usually time and a half or double time, plus the Holiday pay.
Article 40 Section 1(j)(2)
Package car drivers who work on a holiday may make a written request for an eight (8) hour guarantee. Such written request shall be made the last work day prior to the holiday. All time worked by these drivers on a holiday will be paid at the Supplemental holiday rate.